1 \input texinfo @c -*-Texinfo-*-
2 @c Copyright (c) 1991 1992 1993 1994 Free Software Foundation, Inc.
3 @c UPDATE!! On future updates--
4 @c (1) check for new machine-dep cmdline options in
5 @c md_parse_option definitions in config/tc-*.c
6 @c (2) for platform-specific directives, examine md_pseudo_op
8 @c (3) for object-format specific directives, examine obj_pseudo_op
10 @c (4) portable directives in potable[] in read.c
14 @c defaults, config file may override:
17 @include asconfig.texi
19 @c common OR combinations of conditions
36 @set abnormal-separator
40 @settitle Using @value{AS}
43 @settitle Using @value{AS} (@value{TARGET})
45 @setchapternewpage odd
50 @c WARE! Some of the machine-dependent sections contain tables of machine
51 @c instructions. Except in multi-column format, these tables look silly.
52 @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
53 @c the multi-col format is faked within @example sections.
55 @c Again unfortunately, the natural size that fits on a page, for these tables,
56 @c is different depending on whether or not smallbook is turned on.
57 @c This matters, because of order: text flow switches columns at each page
60 @c The format faked in this source works reasonably well for smallbook,
61 @c not well for the default large-page format. This manual expects that if you
62 @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
63 @c tables in question. You can turn on one without the other at your
64 @c discretion, of course.
67 @c the insn tables look just as silly in info files regardless of smallbook,
68 @c might as well show 'em anyways.
74 * As: (as). The GNU assembler.
83 This file documents the GNU Assembler "@value{AS}".
85 Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
87 Permission is granted to make and distribute verbatim copies of
88 this manual provided the copyright notice and this permission notice
89 are preserved on all copies.
92 Permission is granted to process this file through Tex and print the
93 results, provided the printed document carries copying permission
94 notice identical to this one except for the removal of this paragraph
95 (this paragraph not being relevant to the printed manual).
98 Permission is granted to copy and distribute modified versions of this manual
99 under the conditions for verbatim copying, provided that the entire resulting
100 derived work is distributed under the terms of a permission notice identical to
103 Permission is granted to copy and distribute translations of this manual
104 into another language, under the above conditions for modified versions.
108 @title Using @value{AS}
109 @subtitle The GNU Assembler
111 @subtitle for the @value{TARGET} family
114 @subtitle January 1994
117 The Free Software Foundation Inc. thanks The Nice Computer
118 Company of Australia for loaning Dean Elsner to write the
119 first (Vax) version of @code{as} for Project GNU.
120 The proprietors, management and staff of TNCCA thank FSF for
121 distracting the boss while they got some work
124 @author Dean Elsner, Jay Fenlason & friends
128 \hfill {\it Using {\tt @value{AS}}}\par
129 \hfill Edited by Roland Pesch for Cygnus Support\par
131 %"boxit" macro for figures:
132 %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
133 \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
134 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
135 #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
136 \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
139 @vskip 0pt plus 1filll
140 Copyright @copyright{} 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
142 Permission is granted to make and distribute verbatim copies of
143 this manual provided the copyright notice and this permission notice
144 are preserved on all copies.
146 Permission is granted to copy and distribute modified versions of this manual
147 under the conditions for verbatim copying, provided that the entire resulting
148 derived work is distributed under the terms of a permission notice identical to
151 Permission is granted to copy and distribute translations of this manual
152 into another language, under the above conditions for modified versions.
157 @top Using @value{AS}
159 This file is a user guide to the @sc{gnu} assembler @code{@value{AS}}.
161 This version of the file describes @code{@value{AS}} configured to generate
162 code for @value{TARGET} architectures.
165 * Overview:: Overview
166 * Invoking:: Command-Line Options
168 * Sections:: Sections and Relocation
170 * Expressions:: Expressions
171 * Pseudo Ops:: Assembler Directives
172 * Machine Dependencies:: Machine Dependent Features
173 * Acknowledgements:: Who Did What
181 This manual is a user guide to the @sc{gnu} assembler @code{@value{AS}}.
183 This version of the manual describes @code{@value{AS}} configured to generate
184 code for @value{TARGET} architectures.
188 @cindex invocation summary
189 @cindex option summary
190 @cindex summary of options
191 Here is a brief summary of how to invoke @code{@value{AS}}. For details,
192 @pxref{Invoking,,Comand-Line Options}.
194 @c We don't use deffn and friends for the following because they seem
195 @c to be limited to one line for the header.
197 @value{AS} [ -a[dhlns] ] [ -D ] [ -f ] [ --help ]
198 [ -I @var{dir} ] [ -J ] [ -K ] [ -L ] [ -o @var{objfile} ]
199 [ -R ] [ --statistics ] [ -v ] [ -version ] [ --version ]
200 [ -W ] [ -w ] [ -x ] [ -Z ]
202 @c am29k has no machine-dependent assembler options
205 @c Hitachi family chips have no machine-dependent assembler options
208 @c HPPA has no machine-dependent assembler options (yet).
211 [ -Av6 | -Av7 | -Av8 | -Asparclite | -bump ]
214 @c Z8000 has no machine-dependent assembler options
217 @c see md_parse_option in tc-i960.c
218 [ -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC ]
222 [ -l ] [ -m68000 | -m68010 | -m68020 | ... ]
225 [ -nocpp ] [ -EL ] [ -EB ] [ -G @var{num} ] [ -mcpu=@var{CPU} ]
226 [ -mips1 ] [ -mips2 ] [ -mips3 ] [ -m4650 ] [ -no-m4650 ]
227 [ --trap ] [ --break ]
229 [ -- | @var{files} @dots{} ]
234 Turn on listings, in any of a variety of ways:
238 omit debugging directives
241 include high-level source
247 omit forms processing
253 You may combine these options; for example, use @samp{-aln} for assembly
254 listing without forms processing. By itself, @samp{-a} defaults to
255 @samp{-ahls}---that is, all listings turned on.
258 Ignored. This option is accepted for script compatibility with calls to
262 ``fast''---skip whitespace and comment preprocessing (assume source is
266 Print a summary of the command line options and exit.
269 Add directory @var{dir} to the search list for @code{.include} directives.
272 Don't warn about signed overflow.
275 @ifclear DIFF-TBL-KLUGE
276 This option is accepted but has no effect on the @value{TARGET} family.
278 @ifset DIFF-TBL-KLUGE
279 Issue warnings when difference tables altered for long displacements.
283 Keep (in the symbol table) local symbols, starting with @samp{L}.
285 @item -o @var{objfile}
286 Name the object-file output from @code{@value{AS}} @var{objfile}.
289 Fold the data section into the text section.
292 Print the maximum space (in bytes) and total time (in seconds) used by
297 Print the @code{as} version.
300 Print the @code{as} version and exit.
303 Suppress warning messages.
312 Generate an object file even after errors.
314 @item -- | @var{files} @dots{}
315 Standard input, or source files to assemble.
320 The following options are available when @value{AS} is configured for the
321 Intel 80960 processor.
324 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
325 Specify which variant of the 960 architecture is the target.
328 Add code to collect statistics about branches taken.
331 Do not alter compare-and-branch instructions for long displacements;
338 The following options are available when @value{AS} is configured for the
339 Motorola 68000 series.
344 Shorten references to undefined symbols, to one word instead of two.
346 @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030 | -m68040
347 @itemx | -m68302 | -m68331 | -m68332 | -m68333 | -m68340 | -mcpu32
348 Specify what processor in the 68000 family is the target. The default
349 is normally the 68020, but this can be changed at configuration time.
351 @item -m68881 | -m68882 | -mno-68881 | -mno-68882
352 The target machine does (or does not) have a floating-point coprocessor.
353 The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
354 the basic 68000 is not compatible with the 68881, a combination of the
355 two can be specified, since it's possible to do emulation of the
356 coprocessor instructions with the main processor.
358 @item -m68851 | -mno-68851
359 The target machine does (or does not) have a memory-management
360 unit coprocessor. The default is to assume an MMU for 68020 and up.
366 The following options are available when @code{@value{AS}} is configured
367 for the SPARC architecture:
370 @item -Av6 | -Av7 | -Av8 | -Asparclite
371 Explicitly select a variant of the SPARC architecture.
374 Warn when the assembler switches to another architecture.
379 The following options are available when @value{AS} is configured for
384 This option sets the largest size of an object that can be referenced
385 implicitly with the @code{gp} register. It is only accepted for targets that
386 use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
388 @cindex MIPS endianness
389 @cindex endianness, MIPS
390 @cindex big endian output, MIPS
392 Generate ``big endian'' format output.
394 @cindex little endian output, MIPS
396 Generate ``little endian'' format output.
402 Generate code for a particular MIPS Instruction Set Architecture level.
403 @samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
404 @samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
409 Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
410 the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
411 instructions around accesses to the @samp{HI} and @samp{LO} registers.
412 @samp{-no-m4650} turns off this option.
414 @item -mcpu=@var{CPU}
415 Generate code for a particular MIPS cpu. This has little effect on the
416 assembler, but it is passed by @code{@value{GCC}}.
419 @code{@value{AS}} ignores this option. It is accepted for compatibility with
426 Control how to deal with multiplication overflow and division by zero.
427 @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
428 (and only work for Instruction Set Architecture level 2 and higher);
429 @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
435 * Manual:: Structure of this Manual
436 * GNU Assembler:: @value{AS}, the GNU Assembler
437 * Object Formats:: Object File Formats
438 * Command Line:: Command Line
439 * Input Files:: Input Files
440 * Object:: Output (Object) File
441 * Errors:: Error and Warning Messages
445 @section Structure of this Manual
447 @cindex manual, structure and purpose
448 This manual is intended to describe what you need to know to use
449 @sc{gnu} @code{@value{AS}}. We cover the syntax expected in source files, including
450 notation for symbols, constants, and expressions; the directives that
451 @code{@value{AS}} understands; and of course how to invoke @code{@value{AS}}.
454 We also cover special features in the @value{TARGET}
455 configuration of @code{@value{AS}}, including assembler directives.
458 This manual also describes some of the machine-dependent features of
459 various flavors of the assembler.
462 @cindex machine instructions (not covered)
463 On the other hand, this manual is @emph{not} intended as an introduction
464 to programming in assembly language---let alone programming in general!
465 In a similar vein, we make no attempt to introduce the machine
466 architecture; we do @emph{not} describe the instruction set, standard
467 mnemonics, registers or addressing modes that are standard to a
468 particular architecture.
470 You may want to consult the manufacturer's
471 machine architecture manual for this information.
475 For information on the H8/300 machine instruction set, see @cite{H8/300
476 Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H,
477 see @cite{H8/300H Series Programming Manual} (Hitachi).
480 For information on the H8/500 machine instruction set, see @cite{H8/500
481 Series Programming Manual} (Hitachi M21T001).
484 For information on the Hitachi SH machine instruction set, see
485 @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
488 For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
492 @c I think this is premature---pesch@cygnus.com, 17jan1991
494 Throughout this manual, we assume that you are running @dfn{GNU},
495 the portable operating system from the @dfn{Free Software
496 Foundation, Inc.}. This restricts our attention to certain kinds of
497 computer (in particular, the kinds of computers that @sc{gnu} can run on);
498 once this assumption is granted examples and definitions need less
501 @code{@value{AS}} is part of a team of programs that turn a high-level
502 human-readable series of instructions into a low-level
503 computer-readable series of instructions. Different versions of
504 @code{@value{AS}} are used for different kinds of computer.
507 @c There used to be a section "Terminology" here, which defined
508 @c "contents", "byte", "word", and "long". Defining "word" to any
509 @c particular size is confusing when the .word directive may generate 16
510 @c bits on one machine and 32 bits on another; in general, for the user
511 @c version of this manual, none of these terms seem essential to define.
512 @c They were used very little even in the former draft of the manual;
513 @c this draft makes an effort to avoid them (except in names of
517 @section @value{AS}, the GNU Assembler
519 @sc{gnu} @code{as} is really a family of assemblers.
521 This manual describes @code{@value{AS}}, a member of that family which is
522 configured for the @value{TARGET} architectures.
524 If you use (or have used) the @sc{gnu} assembler on one architecture, you
525 should find a fairly similar environment when you use it on another
526 architecture. Each version has much in common with the others,
527 including object file formats, most assembler directives (often called
528 @dfn{pseudo-ops}) and assembler syntax.@refill
530 @cindex purpose of @sc{gnu} @code{@value{AS}}
531 @code{@value{AS}} is primarily intended to assemble the output of the
532 @sc{gnu} C compiler @code{@value{GCC}} for use by the linker
533 @code{@value{LD}}. Nevertheless, we've tried to make @code{@value{AS}}
534 assemble correctly everything that other assemblers for the same
535 machine would assemble.
537 Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
540 @c This remark should appear in generic version of manual; assumption
541 @c here is that generic version sets M680x0.
542 This doesn't mean @code{@value{AS}} always uses the same syntax as another
543 assembler for the same architecture; for example, we know of several
544 incompatible versions of 680x0 assembly language syntax.
547 Unlike older assemblers, @code{@value{AS}} is designed to assemble a source
548 program in one pass of the source file. This has a subtle impact on the
549 @kbd{.org} directive (@pxref{Org,,@code{.org}}).
552 @section Object File Formats
554 @cindex object file format
555 The @sc{gnu} assembler can be configured to produce several alternative
556 object file formats. For the most part, this does not affect how you
557 write assembly language programs; but directives for debugging symbols
558 are typically different in different file formats. @xref{Symbol
559 Attributes,,Symbol Attributes}.
562 On the @value{TARGET}, @code{@value{AS}} is configured to produce
563 @value{OBJ-NAME} format object files.
565 @c The following should exhaust all configs that set MULTI-OBJ, ideally
567 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
568 @code{a.out} or COFF format object files.
571 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
572 @code{b.out} or COFF format object files.
575 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
576 SOM or ELF format object files.
581 @section Command Line
583 @cindex command line conventions
584 After the program name @code{@value{AS}}, the command line may contain
585 options and file names. Options may appear in any order, and may be
586 before, after, or between file names. The order of file names is
589 @cindex standard input, as input file
591 @file{--} (two hyphens) by itself names the standard input file
592 explicitly, as one of the files for @code{@value{AS}} to assemble.
594 @cindex options, command line
595 Except for @samp{--} any command line argument that begins with a
596 hyphen (@samp{-}) is an option. Each option changes the behavior of
597 @code{@value{AS}}. No option changes the way another option works. An
598 option is a @samp{-} followed by one or more letters; the case of
599 the letter is important. All options are optional.
601 Some options expect exactly one file name to follow them. The file
602 name may either immediately follow the option's letter (compatible
603 with older assemblers) or it may be the next command argument (@sc{gnu}
604 standard). These two command lines are equivalent:
607 @value{AS} -o my-object-file.o mumble.s
608 @value{AS} -omy-object-file.o mumble.s
615 @cindex source program
617 We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
618 describe the program input to one run of @code{@value{AS}}. The program may
619 be in one or more files; how the source is partitioned into files
620 doesn't change the meaning of the source.
622 @c I added "con" prefix to "catenation" just to prove I can overcome my
623 @c APL training... pesch@cygnus.com
624 The source program is a concatenation of the text in all the files, in the
627 Each time you run @code{@value{AS}} it assembles exactly one source
628 program. The source program is made up of one or more files.
629 (The standard input is also a file.)
631 You give @code{@value{AS}} a command line that has zero or more input file
632 names. The input files are read (from left file name to right). A
633 command line argument (in any position) that has no special meaning
634 is taken to be an input file name.
636 If you give @code{@value{AS}} no file names it attempts to read one input file
637 from the @code{@value{AS}} standard input, which is normally your terminal. You
638 may have to type @key{ctl-D} to tell @code{@value{AS}} there is no more program
641 Use @samp{--} if you need to explicitly name the standard input file
642 in your command line.
644 If the source is empty, @code{@value{AS}} produces a small, empty object
647 @subheading Filenames and Line-numbers
649 @cindex input file linenumbers
650 @cindex line numbers, in input files
651 There are two ways of locating a line in the input file (or files) and
652 either may be used in reporting error messages. One way refers to a line
653 number in a physical file; the other refers to a line number in a
654 ``logical'' file. @xref{Errors, ,Error and Warning Messages}.
656 @dfn{Physical files} are those files named in the command line given
657 to @code{@value{AS}}.
659 @dfn{Logical files} are simply names declared explicitly by assembler
660 directives; they bear no relation to physical files. Logical file names
661 help error messages reflect the original source file, when @code{@value{AS}}
662 source is itself synthesized from other files.
663 @xref{App-File,,@code{.app-file}}.
666 @section Output (Object) File
672 Every time you run @code{@value{AS}} it produces an output file, which is
673 your assembly language program translated into numbers. This file
674 is the object file. Its default name is
682 @code{b.out} when @code{@value{AS}} is configured for the Intel 80960.
684 You can give it another name by using the @code{-o} option. Conventionally,
685 object file names end with @file{.o}. The default name is used for historical
686 reasons: older assemblers were capable of assembling self-contained programs
687 directly into a runnable program. (For some formats, this isn't currently
688 possible, but it can be done for the @code{a.out} format.)
692 The object file is meant for input to the linker @code{@value{LD}}. It contains
693 assembled program code, information to help @code{@value{LD}} integrate
694 the assembled program into a runnable file, and (optionally) symbolic
695 information for the debugger.
697 @c link above to some info file(s) like the description of a.out.
698 @c don't forget to describe GNU info as well as Unix lossage.
701 @section Error and Warning Messages
703 @cindex error messsages
704 @cindex warning messages
705 @cindex messages from @code{@value{AS}}
706 @code{@value{AS}} may write warnings and error messages to the standard error
707 file (usually your terminal). This should not happen when a compiler
708 runs @code{@value{AS}} automatically. Warnings report an assumption made so
709 that @code{@value{AS}} could keep assembling a flawed program; errors report a
710 grave problem that stops the assembly.
712 @cindex format of warning messages
713 Warning messages have the format
716 file_name:@b{NNN}:Warning Message Text
720 @cindex line numbers, in warnings/errors
721 (where @b{NNN} is a line number). If a logical file name has been given
722 (@pxref{App-File,,@code{.app-file}}) it is used for the filename,
723 otherwise the name of the current input file is used. If a logical line
726 (@pxref{Line,,@code{.line}})
730 (@pxref{Line,,@code{.line}})
733 (@pxref{Ln,,@code{.ln}})
736 then it is used to calculate the number printed,
737 otherwise the actual line in the current source file is printed. The
738 message text is intended to be self explanatory (in the grand Unix
741 @cindex format of error messages
742 Error messages have the format
744 file_name:@b{NNN}:FATAL:Error Message Text
746 The file name and line number are derived as for warning
747 messages. The actual message text may be rather less explanatory
748 because many of them aren't supposed to happen.
751 @chapter Command-Line Options
753 @cindex options, all versions of @code{@value{AS}}
754 This chapter describes command-line options available in @emph{all}
755 versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
757 to the @value{TARGET}.
760 to particular machine architectures.
763 If you are invoking @code{@value{AS}} via the @sc{gnu} C compiler (version 2), you
764 can use the @samp{-Wa} option to pass arguments through to the
765 assembler. The assembler arguments must be separated from each other
766 (and the @samp{-Wa}) by commas. For example:
769 gcc -c -g -O -Wa,-alh,-L file.c
773 emits a listing to standard output with high-level
776 Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
777 command-line options are automatically passed to the assembler by the compiler.
778 (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
779 precisely what options it passes to each compilation pass, including the
783 * a:: -a[dhlns] enable listings
784 * D:: -D for compatibility
785 * f:: -f to work faster
786 * I:: -I for .include search path
787 @ifclear DIFF-TBL-KLUGE
788 * K:: -K for compatibility
790 @ifset DIFF-TBL-KLUGE
791 * K:: -K for difference tables
794 * L:: -L to retain local labels
795 * o:: -o to name the object file
796 * R:: -R to join data and text sections
797 * statistics:: --statistics to see statistics about assembly
798 * v:: -v to announce version
799 * W:: -W to suppress warnings
800 * Z:: -Z to make object file even after errors
804 @section Enable Listings: @code{-a[dhlns]}
812 @cindex listings, enabling
813 @cindex assembly listings, enabling
815 These options enable listing output from the assembler. By itself,
816 @samp{-a} requests high-level, assembly, and symbols listing.
817 You can use other letters to select specific options for the list:
818 @samp{-ah} requests a high-level language listing,
819 @samp{-al} requests an output-program assembly listing, and
820 @samp{-as} requests a symbol table listing.
821 High-level listings require that a compiler debugging option like
822 @samp{-g} be used, and that assembly listings (@samp{-al}) be requested
825 Use the @samp{-ad} option to omit debugging directives from the
828 Once you have specified one of these options, you can further control
829 listing output and its appearance using the directives @code{.list},
830 @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
832 The @samp{-an} option turns off all forms processing.
833 If you do not request listing output with one of the @samp{-a} options, the
834 listing-control directives have no effect.
836 The letters after @samp{-a} may be combined into one option,
837 @emph{e.g.}, @samp{-aln}.
843 This option has no effect whatsoever, but it is accepted to make it more
844 likely that scripts written for other assemblers also work with
848 @section Work Faster: @code{-f}
851 @cindex trusted compiler
852 @cindex faster processing (@code{-f})
853 @samp{-f} should only be used when assembling programs written by a
854 (trusted) compiler. @samp{-f} stops the assembler from doing whitespace
855 and comment preprocessing on
856 the input file(s) before assembling them. @xref{Preprocessing,
860 @emph{Warning:} if you use @samp{-f} when the files actually need to be
861 preprocessed (if they contain comments, for example), @code{@value{AS}} does
866 @section @code{.include} search path: @code{-I} @var{path}
868 @kindex -I @var{path}
869 @cindex paths for @code{.include}
870 @cindex search path for @code{.include}
871 @cindex @code{include} directive search path
872 Use this option to add a @var{path} to the list of directories
873 @code{@value{AS}} searches for files specified in @code{.include}
874 directives (@pxref{Include,,@code{.include}}). You may use @code{-I} as
875 many times as necessary to include a variety of paths. The current
876 working directory is always searched first; after that, @code{@value{AS}}
877 searches any @samp{-I} directories in the same order as they were
878 specified (left to right) on the command line.
881 @section Difference Tables: @code{-K}
884 @ifclear DIFF-TBL-KLUGE
885 On the @value{TARGET} family, this option is allowed, but has no effect. It is
886 permitted for compatibility with the @sc{gnu} assembler on other platforms,
887 where it can be used to warn when the assembler alters the machine code
888 generated for @samp{.word} directives in difference tables. The @value{TARGET}
889 family does not have the addressing limitations that sometimes lead to this
890 alteration on other platforms.
893 @ifset DIFF-TBL-KLUGE
894 @cindex difference tables, warning
895 @cindex warning for altered difference tables
896 @code{@value{AS}} sometimes alters the code emitted for directives of the form
897 @samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
898 You can use the @samp{-K} option if you want a warning issued when this
903 @section Include Local Labels: @code{-L}
906 @cindex local labels, retaining in output
907 Labels beginning with @samp{L} (upper case only) are called @dfn{local
908 labels}. @xref{Symbol Names}. Normally you do not see such labels when
909 debugging, because they are intended for the use of programs (like
910 compilers) that compose assembler programs, not for your notice.
911 Normally both @code{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
912 normally debug with them.
914 This option tells @code{@value{AS}} to retain those @samp{L@dots{}} symbols
915 in the object file. Usually if you do this you also tell the linker
916 @code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
918 By default, a local label is any label beginning with @samp{L}, but each
919 target is allowed to redefine the local label prefix.
921 On the HPPA local labels begin with @samp{L$}.
925 @section Name the Object File: @code{-o}
928 @cindex naming object file
929 @cindex object file name
930 There is always one object file output when you run @code{@value{AS}}. By
931 default it has the name
934 @file{a.out} (or @file{b.out}, for Intel 960 targets only).
948 You use this option (which takes exactly one filename) to give the
949 object file a different name.
951 Whatever the object file is called, @code{@value{AS}} overwrites any
952 existing file of the same name.
955 @section Join Data and Text Sections: @code{-R}
958 @cindex data and text sections, joining
959 @cindex text and data sections, joining
960 @cindex joining text and data sections
961 @cindex merging text and data sections
962 @code{-R} tells @code{@value{AS}} to write the object file as if all
963 data-section data lives in the text section. This is only done at
964 the very last moment: your binary data are the same, but data
965 section parts are relocated differently. The data section part of
966 your object file is zero bytes long because all its bytes are
967 appended to the text section. (@xref{Sections,,Sections and Relocation}.)
969 When you specify @code{-R} it would be possible to generate shorter
970 address displacements (because we do not have to cross between text and
971 data section). We refrain from doing this simply for compatibility with
972 older versions of @code{@value{AS}}. In future, @code{-R} may work this way.
975 When @code{@value{AS}} is configured for COFF output,
976 this option is only useful if you use sections named @samp{.text} and
981 @code{-R} is not supported for any of the HPPA targets. Using
982 @code{-R} generates a warning from @code{@value{AS}}.
986 @section Display Assembly Statistics: @code{--statistics}
989 @cindex statistics, about assembly
990 @cindex time, total for assembly
991 @cindex space used, maximum for assembly
992 Use @samp{--statistics} to display two statistics about the resources used by
993 @code{@value{AS}}: the maximum amount of space allocated during the assembly
994 (in bytes), and the total execution time taken for the assembly (in @sc{cpu}
998 @section Announce Version: @code{-v}
1002 @cindex @code{@value{AS}} version
1003 @cindex version of @code{@value{AS}}
1004 You can find out what version of as is running by including the
1005 option @samp{-v} (which you can also spell as @samp{-version}) on the
1009 @section Suppress Warnings: @code{-W}
1012 @cindex suppressing warnings
1013 @cindex warnings, suppressing
1014 @code{@value{AS}} should never give a warning or error message when
1015 assembling compiler output. But programs written by people often
1016 cause @code{@value{AS}} to give a warning that a particular assumption was
1017 made. All such warnings are directed to the standard error file.
1018 If you use this option, no warnings are issued. This option only
1019 affects the warning messages: it does not change any particular of how
1020 @code{@value{AS}} assembles your file. Errors, which stop the assembly, are
1024 @section Generate Object File in Spite of Errors: @code{-Z}
1025 @cindex object file, after errors
1026 @cindex errors, continuing after
1027 After an error message, @code{@value{AS}} normally produces no output. If for
1028 some reason you are interested in object file output even after
1029 @code{@value{AS}} gives an error message on your program, use the @samp{-Z}
1030 option. If there are any errors, @code{@value{AS}} continues anyways, and
1031 writes an object file after a final warning message of the form @samp{@var{n}
1032 errors, @var{m} warnings, generating bad object file.}
1037 @cindex machine-independent syntax
1038 @cindex syntax, machine-independent
1039 This chapter describes the machine-independent syntax allowed in a
1040 source file. @code{@value{AS}} syntax is similar to what many other
1041 assemblers use; it is inspired by the BSD 4.2
1046 assembler, except that @code{@value{AS}} does not assemble Vax bit-fields.
1050 * Preprocessing:: Preprocessing
1051 * Whitespace:: Whitespace
1052 * Comments:: Comments
1053 * Symbol Intro:: Symbols
1054 * Statements:: Statements
1055 * Constants:: Constants
1059 @section Preprocessing
1061 @cindex preprocessing
1062 The @code{@value{AS}} internal preprocessor:
1064 @cindex whitespace, removed by preprocessor
1066 adjusts and removes extra whitespace. It leaves one space or tab before
1067 the keywords on a line, and turns any other whitespace on the line into
1070 @cindex comments, removed by preprocessor
1072 removes all comments, replacing them with a single space, or an
1073 appropriate number of newlines.
1075 @cindex constants, converted by preprocessor
1077 converts character constants into the appropriate numeric values.
1080 It does not do macro processing, include file handling, or
1081 anything else you may get from your C compiler's preprocessor. You can
1082 do include file processing with the @code{.include} directive
1083 (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
1084 to get other ``CPP'' style preprocessing, by giving the input file a
1085 @samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
1086 Output, gcc.info, Using GNU CC}.
1088 Excess whitespace, comments, and character constants
1089 cannot be used in the portions of the input text that are not
1092 @cindex turning preprocessing on and off
1093 @cindex preprocessing, turning on and off
1096 If the first line of an input file is @code{#NO_APP} or if you use the
1097 @samp{-f} option, whitespace and comments are not removed from the input file.
1098 Within an input file, you can ask for whitespace and comment removal in
1099 specific portions of the by putting a line that says @code{#APP} before the
1100 text that may contain whitespace or comments, and putting a line that says
1101 @code{#NO_APP} after this text. This feature is mainly intend to support
1102 @code{asm} statements in compilers whose output is otherwise free of comments
1109 @dfn{Whitespace} is one or more blanks or tabs, in any order.
1110 Whitespace is used to separate symbols, and to make programs neater for
1111 people to read. Unless within character constants
1112 (@pxref{Characters,,Character Constants}), any whitespace means the same
1113 as exactly one space.
1119 There are two ways of rendering comments to @code{@value{AS}}. In both
1120 cases the comment is equivalent to one space.
1122 Anything from @samp{/*} through the next @samp{*/} is a comment.
1123 This means you may not nest these comments.
1127 The only way to include a newline ('\n') in a comment
1128 is to use this sort of comment.
1131 /* This sort of comment does not nest. */
1134 @cindex line comment character
1135 Anything from the @dfn{line comment} character to the next newline
1136 is considered a comment and is ignored. The line comment character is
1138 @samp{#} on the Vax;
1141 @samp{#} on the i960;
1144 @samp{!} on the SPARC;
1147 @samp{|} on the 680x0;
1150 @samp{;} for the AMD 29K family;
1153 @samp{;} for the H8/300 family;
1156 @samp{!} for the H8/500 family;
1159 @samp{;} for the HPPA;
1162 @samp{!} for the Hitachi SH;
1165 @samp{!} for the Z8000;
1167 see @ref{Machine Dependencies}. @refill
1168 @c FIXME What about i386, m88k, i860?
1171 On some machines there are two different line comment characters. One
1172 character only begins a comment if it is the first non-whitespace character on
1173 a line, while the other always begins a comment.
1177 @cindex lines starting with @code{#}
1178 @cindex logical line numbers
1179 To be compatible with past assemblers, lines that begin with @samp{#} have a
1180 special interpretation. Following the @samp{#} should be an absolute
1181 expression (@pxref{Expressions}): the logical line number of the @emph{next}
1182 line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
1183 new logical file name. The rest of the line, if any, should be whitespace.
1185 If the first non-whitespace characters on the line are not numeric,
1186 the line is ignored. (Just like a comment.)
1189 # This is an ordinary comment.
1190 # 42-6 "new_file_name" # New logical file name
1191 # This is logical line # 36.
1193 This feature is deprecated, and may disappear from future versions
1194 of @code{@value{AS}}.
1199 @cindex characters used in symbols
1200 @ifclear SPECIAL-SYMS
1201 A @dfn{symbol} is one or more characters chosen from the set of all
1202 letters (both upper and lower case), digits and the three characters
1208 A @dfn{symbol} is one or more characters chosen from the set of all
1209 letters (both upper and lower case), digits and the three characters
1210 @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
1216 On most machines, you can also use @code{$} in symbol names; exceptions
1217 are noted in @ref{Machine Dependencies}.
1219 No symbol may begin with a digit. Case is significant.
1220 There is no length limit: all characters are significant. Symbols are
1221 delimited by characters not in that set, or by the beginning of a file
1222 (since the source program must end with a newline, the end of a file is
1223 not a possible symbol delimiter). @xref{Symbols}.
1224 @cindex length of symbols
1229 @cindex statements, structure of
1230 @cindex line separator character
1231 @cindex statement separator character
1233 @ifclear abnormal-separator
1234 A @dfn{statement} ends at a newline character (@samp{\n}) or at a
1235 semicolon (@samp{;}). The newline or semicolon is considered part of
1236 the preceding statement. Newlines and semicolons within character
1237 constants are an exception: they do not end statements.
1239 @ifset abnormal-separator
1241 A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at''
1242 sign (@samp{@@}). The newline or at sign is considered part of the
1243 preceding statement. Newlines and at signs within character constants
1244 are an exception: they do not end statements.
1247 A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
1248 point (@samp{!}). The newline or exclamation point is considered part of the
1249 preceding statement. Newlines and exclamation points within character
1250 constants are an exception: they do not end statements.
1253 A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
1254 H8/300) a dollar sign (@samp{$}); or (for the
1257 (@samp{;}). The newline or separator character is considered part of
1258 the preceding statement. Newlines and separators within character
1259 constants are an exception: they do not end statements.
1264 A @dfn{statement} ends at a newline character (@samp{\n}) or line
1265 separator character. (The line separator is usually @samp{;}, unless
1266 this conflicts with the comment character; @pxref{Machine Dependencies}.) The
1267 newline or separator character is considered part of the preceding
1268 statement. Newlines and separators within character constants are an
1269 exception: they do not end statements.
1272 @cindex newline, required at file end
1273 @cindex EOF, newline must precede
1274 It is an error to end any statement with end-of-file: the last
1275 character of any input file should be a newline.@refill
1277 @cindex continuing statements
1278 @cindex multi-line statements
1279 @cindex statement on multiple lines
1280 You may write a statement on more than one line if you put a
1281 backslash (@kbd{\}) immediately in front of any newlines within the
1282 statement. When @code{@value{AS}} reads a backslashed newline both
1283 characters are ignored. You can even put backslashed newlines in
1284 the middle of symbol names without changing the meaning of your
1287 An empty statement is allowed, and may include whitespace. It is ignored.
1289 @cindex instructions and directives
1290 @cindex directives and instructions
1291 @c "key symbol" is not used elsewhere in the document; seems pedantic to
1292 @c @defn{} it in that case, as was done previously... pesch@cygnus.com,
1294 A statement begins with zero or more labels, optionally followed by a
1295 key symbol which determines what kind of statement it is. The key
1296 symbol determines the syntax of the rest of the statement. If the
1297 symbol begins with a dot @samp{.} then the statement is an assembler
1298 directive: typically valid for any computer. If the symbol begins with
1299 a letter the statement is an assembly language @dfn{instruction}: it
1300 assembles into a machine language instruction.
1302 Different versions of @code{@value{AS}} for different computers
1303 recognize different instructions. In fact, the same symbol may
1304 represent a different instruction in a different computer's assembly
1308 @cindex @code{:} (label)
1309 @cindex label (@code{:})
1310 A label is a symbol immediately followed by a colon (@code{:}).
1311 Whitespace before a label or after a colon is permitted, but you may not
1312 have whitespace between a label's symbol and its colon. @xref{Labels}.
1315 For HPPA targets, labels need not be immediately followed by a colon, but
1316 the definition of a label must begin in column zero. This also implies that
1317 only one label may be defined on each line.
1321 label: .directive followed by something
1322 another_label: # This is an empty statement.
1323 instruction operand_1, operand_2, @dots{}
1330 A constant is a number, written so that its value is known by
1331 inspection, without knowing any context. Like this:
1334 .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
1335 .ascii "Ring the bell\7" # A string constant.
1336 .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
1337 .float 0f-314159265358979323846264338327\
1338 95028841971.693993751E-40 # - pi, a flonum.
1343 * Characters:: Character Constants
1344 * Numbers:: Number Constants
1348 @subsection Character Constants
1350 @cindex character constants
1351 @cindex constants, character
1352 There are two kinds of character constants. A @dfn{character} stands
1353 for one character in one byte and its value may be used in
1354 numeric expressions. String constants (properly called string
1355 @emph{literals}) are potentially many bytes and their values may not be
1356 used in arithmetic expressions.
1360 * Chars:: Characters
1364 @subsubsection Strings
1366 @cindex string constants
1367 @cindex constants, string
1368 A @dfn{string} is written between double-quotes. It may contain
1369 double-quotes or null characters. The way to get special characters
1370 into a string is to @dfn{escape} these characters: precede them with
1371 a backslash @samp{\} character. For example @samp{\\} represents
1372 one backslash: the first @code{\} is an escape which tells
1373 @code{@value{AS}} to interpret the second character literally as a backslash
1374 (which prevents @code{@value{AS}} from recognizing the second @code{\} as an
1375 escape character). The complete list of escapes follows.
1377 @cindex escape codes, character
1378 @cindex character escape codes
1381 @c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
1384 @cindex @code{\b} (backspace character)
1385 @cindex backspace (@code{\b})
1386 Mnemonic for backspace; for ASCII this is octal code 010.
1389 @c Mnemonic for EOText; for ASCII this is octal code 004.
1392 @cindex @code{\f} (formfeed character)
1393 @cindex formfeed (@code{\f})
1394 Mnemonic for FormFeed; for ASCII this is octal code 014.
1397 @cindex @code{\n} (newline character)
1398 @cindex newline (@code{\n})
1399 Mnemonic for newline; for ASCII this is octal code 012.
1402 @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
1405 @cindex @code{\r} (carriage return character)
1406 @cindex carriage return (@code{\r})
1407 Mnemonic for carriage-Return; for ASCII this is octal code 015.
1410 @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
1411 @c other assemblers.
1414 @cindex @code{\t} (tab)
1415 @cindex tab (@code{\t})
1416 Mnemonic for horizontal Tab; for ASCII this is octal code 011.
1419 @c Mnemonic for Vertical tab; for ASCII this is octal code 013.
1420 @c @item \x @var{digit} @var{digit} @var{digit}
1421 @c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
1423 @item \ @var{digit} @var{digit} @var{digit}
1424 @cindex @code{\@var{ddd}} (octal character code)
1425 @cindex octal character code (@code{\@var{ddd}})
1426 An octal character code. The numeric code is 3 octal digits.
1427 For compatibility with other Unix systems, 8 and 9 are accepted as digits:
1428 for example, @code{\008} has the value 010, and @code{\009} the value 011.
1431 @item \@code{x} @var{hex-digit} @var{hex-digit}
1432 @cindex @code{\@var{xdd}} (hex character code)
1433 @cindex hex character code (@code{\@var{xdd}})
1434 A hex character code. The numeric code is 2 hexadecimal digits. Either
1435 upper or lower case @code{x} works.
1439 @cindex @code{\\} (@samp{\} character)
1440 @cindex backslash (@code{\\})
1441 Represents one @samp{\} character.
1444 @c Represents one @samp{'} (accent acute) character.
1445 @c This is needed in single character literals
1446 @c (@xref{Characters,,Character Constants}.) to represent
1450 @cindex @code{\"} (doublequote character)
1451 @cindex doublequote (@code{\"})
1452 Represents one @samp{"} character. Needed in strings to represent
1453 this character, because an unescaped @samp{"} would end the string.
1455 @item \ @var{anything-else}
1456 Any other character when escaped by @kbd{\} gives a warning, but
1457 assembles as if the @samp{\} was not present. The idea is that if
1458 you used an escape sequence you clearly didn't want the literal
1459 interpretation of the following character. However @code{@value{AS}} has no
1460 other interpretation, so @code{@value{AS}} knows it is giving you the wrong
1461 code and warns you of the fact.
1464 Which characters are escapable, and what those escapes represent,
1465 varies widely among assemblers. The current set is what we think
1466 the BSD 4.2 assembler recognizes, and is a subset of what most C
1467 compilers recognize. If you are in doubt, do not use an escape
1471 @subsubsection Characters
1473 @cindex single character constant
1474 @cindex character, single
1475 @cindex constant, single character
1476 A single character may be written as a single quote immediately
1477 followed by that character. The same escapes apply to characters as
1478 to strings. So if you want to write the character backslash, you
1479 must write @kbd{'\\} where the first @code{\} escapes the second
1480 @code{\}. As you can see, the quote is an acute accent, not a
1481 grave accent. A newline
1483 @ifclear abnormal-separator
1484 (or semicolon @samp{;})
1486 @ifset abnormal-separator
1488 (or at sign @samp{@@})
1491 (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
1497 immediately following an acute accent is taken as a literal character
1498 and does not count as the end of a statement. The value of a character
1499 constant in a numeric expression is the machine's byte-wide code for
1500 that character. @code{@value{AS}} assumes your character code is ASCII:
1501 @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
1504 @subsection Number Constants
1506 @cindex constants, number
1507 @cindex number constants
1508 @code{@value{AS}} distinguishes three kinds of numbers according to how they
1509 are stored in the target machine. @emph{Integers} are numbers that
1510 would fit into an @code{int} in the C language. @emph{Bignums} are
1511 integers, but they are stored in more than 32 bits. @emph{Flonums}
1512 are floating point numbers, described below.
1515 * Integers:: Integers
1520 * Bit Fields:: Bit Fields
1526 @subsubsection Integers
1528 @cindex constants, integer
1530 @cindex binary integers
1531 @cindex integers, binary
1532 A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
1533 the binary digits @samp{01}.
1535 @cindex octal integers
1536 @cindex integers, octal
1537 An octal integer is @samp{0} followed by zero or more of the octal
1538 digits (@samp{01234567}).
1540 @cindex decimal integers
1541 @cindex integers, decimal
1542 A decimal integer starts with a non-zero digit followed by zero or
1543 more digits (@samp{0123456789}).
1545 @cindex hexadecimal integers
1546 @cindex integers, hexadecimal
1547 A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
1548 more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
1550 Integers have the usual values. To denote a negative integer, use
1551 the prefix operator @samp{-} discussed under expressions
1552 (@pxref{Prefix Ops,,Prefix Operators}).
1555 @subsubsection Bignums
1558 @cindex constants, bignum
1559 A @dfn{bignum} has the same syntax and semantics as an integer
1560 except that the number (or its negative) takes more than 32 bits to
1561 represent in binary. The distinction is made because in some places
1562 integers are permitted while bignums are not.
1565 @subsubsection Flonums
1567 @cindex floating point numbers
1568 @cindex constants, floating point
1570 @cindex precision, floating point
1571 A @dfn{flonum} represents a floating point number. The translation is
1572 indirect: a decimal floating point number from the text is converted by
1573 @code{@value{AS}} to a generic binary floating point number of more than
1574 sufficient precision. This generic floating point number is converted
1575 to a particular computer's floating point format (or formats) by a
1576 portion of @code{@value{AS}} specialized to that computer.
1578 A flonum is written by writing (in order)
1583 (@samp{0} is optional on the HPPA.)
1587 A letter, to tell @code{@value{AS}} the rest of the number is a flonum.
1589 @kbd{e} is recommended. Case is not important.
1591 @c FIXME: verify if flonum syntax really this vague for most cases
1592 (Any otherwise illegal letter works here, but that might be changed. Vax BSD
1593 4.2 assembler seems to allow any of @samp{defghDEFGH}.)
1596 On the H8/300, H8/500,
1598 and AMD 29K architectures, the letter must be
1599 one of the letters @samp{DFPRSX} (in upper or lower case).
1601 On the Intel 960 architecture, the letter must be
1602 one of the letters @samp{DFT} (in upper or lower case).
1604 On the HPPA architecture, the letter must be @samp{E} (upper case only).
1608 One of the letters @samp{DFPRSX} (in upper or lower case).
1611 One of the letters @samp{DFPRSX} (in upper or lower case).
1614 One of the letters @samp{DFT} (in upper or lower case).
1617 The letter @samp{E} (upper case only).
1622 An optional sign: either @samp{+} or @samp{-}.
1625 An optional @dfn{integer part}: zero or more decimal digits.
1628 An optional @dfn{fractional part}: @samp{.} followed by zero
1629 or more decimal digits.
1632 An optional exponent, consisting of:
1636 An @samp{E} or @samp{e}.
1637 @c I can't find a config where "EXP_CHARS" is other than 'eE', but in
1638 @c principle this can perfectly well be different on different targets.
1640 Optional sign: either @samp{+} or @samp{-}.
1642 One or more decimal digits.
1647 At least one of the integer part or the fractional part must be
1648 present. The floating point number has the usual base-10 value.
1650 @code{@value{AS}} does all processing using integers. Flonums are computed
1651 independently of any floating point hardware in the computer running
1656 @c Bit fields are written as a general facility but are also controlled
1657 @c by a conditional-compilation flag---which is as of now (21mar91)
1658 @c turned on only by the i960 config of GAS.
1660 @subsubsection Bit Fields
1663 @cindex constants, bit field
1664 You can also define numeric constants as @dfn{bit fields}.
1665 specify two numbers separated by a colon---
1667 @var{mask}:@var{value}
1670 @code{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
1673 The resulting number is then packed
1675 @c this conditional paren in case bit fields turned on elsewhere than 960
1676 (in host-dependent byte order)
1678 into a field whose width depends on which assembler directive has the
1679 bit-field as its argument. Overflow (a result from the bitwise and
1680 requiring more binary digits to represent) is not an error; instead,
1681 more constants are generated, of the specified width, beginning with the
1682 least significant digits.@refill
1684 The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
1685 @code{.short}, and @code{.word} accept bit-field arguments.
1690 @chapter Sections and Relocation
1695 * Secs Background:: Background
1696 * Ld Sections:: @value{LD} Sections
1697 * As Sections:: @value{AS} Internal Sections
1698 * Sub-Sections:: Sub-Sections
1702 @node Secs Background
1705 Roughly, a section is a range of addresses, with no gaps; all data
1706 ``in'' those addresses is treated the same for some particular purpose.
1707 For example there may be a ``read only'' section.
1709 @cindex linker, and assembler
1710 @cindex assembler, and linker
1711 The linker @code{@value{LD}} reads many object files (partial programs) and
1712 combines their contents to form a runnable program. When @code{@value{AS}}
1713 emits an object file, the partial program is assumed to start at address 0.
1714 @code{@value{LD}} assigns the final addresses for the partial program, so that
1715 different partial programs do not overlap. This is actually an
1716 oversimplification, but it suffices to explain how @code{@value{AS}} uses
1719 @code{@value{LD}} moves blocks of bytes of your program to their run-time
1720 addresses. These blocks slide to their run-time addresses as rigid
1721 units; their length does not change and neither does the order of bytes
1722 within them. Such a rigid unit is called a @emph{section}. Assigning
1723 run-time addresses to sections is called @dfn{relocation}. It includes
1724 the task of adjusting mentions of object-file addresses so they refer to
1725 the proper run-time addresses.
1727 For the H8/300 and H8/500,
1728 and for the Hitachi SH,
1729 @code{@value{AS}} pads sections if needed to
1730 ensure they end on a word (sixteen bit) boundary.
1733 @cindex standard @code{@value{AS}} sections
1734 An object file written by @code{@value{AS}} has at least three sections, any
1735 of which may be empty. These are named @dfn{text}, @dfn{data} and
1740 When it generates COFF output,
1742 @code{@value{AS}} can also generate whatever other named sections you specify
1743 using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
1744 If you do not use any directives that place output in the @samp{.text}
1745 or @samp{.data} sections, these sections still exist, but are empty.
1750 When @code{@value{AS}} generates SOM or ELF output for the HPPA,
1752 @code{@value{AS}} can also generate whatever other named sections you
1753 specify using the @samp{.space} and @samp{.subspace} directives. See
1754 @cite{HP9000 Series 800 Assembly Language Reference Manual}
1755 (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
1756 assembler directives.
1759 Additionally, @code{@value{AS}} uses different names for the standard
1760 text, data, and bss sections when generating SOM output. Program text
1761 is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
1762 BSS into @samp{$BSS$}.
1766 Within the object file, the text section starts at address @code{0}, the
1767 data section follows, and the bss section follows the data section.
1770 When generating either SOM or ELF output files on the HPPA, the text
1771 section starts at address @code{0}, the data section at address
1772 @code{0x4000000}, and the bss section follows the data section.
1775 To let @code{@value{LD}} know which data changes when the sections are
1776 relocated, and how to change that data, @code{@value{AS}} also writes to the
1777 object file details of the relocation needed. To perform relocation
1778 @code{@value{LD}} must know, each time an address in the object
1782 Where in the object file is the beginning of this reference to
1785 How long (in bytes) is this reference?
1787 Which section does the address refer to? What is the numeric value of
1789 (@var{address}) @minus{} (@var{start-address of section})?
1792 Is the reference to an address ``Program-Counter relative''?
1795 @cindex addresses, format of
1796 @cindex section-relative addressing
1797 In fact, every address @code{@value{AS}} ever uses is expressed as
1799 (@var{section}) + (@var{offset into section})
1802 Further, most expressions @code{@value{AS}} computes have this section-relative
1805 (For some object formats, such as SOM for the HPPA, some expressions are
1806 symbol-relative instead.)
1809 In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
1810 @var{N} into section @var{secname}.''
1812 Apart from text, data and bss sections you need to know about the
1813 @dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
1814 addresses in the absolute section remain unchanged. For example, address
1815 @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
1816 @code{@value{LD}}. Although the linker never arranges two partial programs'
1817 data sections with overlapping addresses after linking, @emph{by definition}
1818 their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
1819 part of a program is always the same address when the program is running as
1820 address @code{@{absolute@ 239@}} in any other part of the program.
1822 The idea of sections is extended to the @dfn{undefined} section. Any
1823 address whose section is unknown at assembly time is by definition
1824 rendered @{undefined @var{U}@}---where @var{U} is filled in later.
1825 Since numbers are always defined, the only way to generate an undefined
1826 address is to mention an undefined symbol. A reference to a named
1827 common block would be such a symbol: its value is unknown at assembly
1828 time so it has section @emph{undefined}.
1830 By analogy the word @emph{section} is used to describe groups of sections in
1831 the linked program. @code{@value{LD}} puts all partial programs' text
1832 sections in contiguous addresses in the linked program. It is
1833 customary to refer to the @emph{text section} of a program, meaning all
1834 the addresses of all partial programs' text sections. Likewise for
1835 data and bss sections.
1837 Some sections are manipulated by @code{@value{LD}}; others are invented for
1838 use of @code{@value{AS}} and have no meaning except during assembly.
1841 @section @value{LD} Sections
1842 @code{@value{LD}} deals with just four kinds of sections, summarized below.
1847 @cindex named sections
1848 @cindex sections, named
1849 @item named sections
1852 @cindex text section
1853 @cindex data section
1857 These sections hold your program. @code{@value{AS}} and @code{@value{LD}} treat them as
1858 separate but equal sections. Anything you can say of one section is
1861 When the program is running, however, it is
1862 customary for the text section to be unalterable. The
1863 text section is often shared among processes: it contains
1864 instructions, constants and the like. The data section of a running
1865 program is usually alterable: for example, C variables would be stored
1866 in the data section.
1871 This section contains zeroed bytes when your program begins running. It
1872 is used to hold unitialized variables or common storage. The length of
1873 each partial program's bss section is important, but because it starts
1874 out containing zeroed bytes there is no need to store explicit zero
1875 bytes in the object file. The bss section was invented to eliminate
1876 those explicit zeros from object files.
1878 @cindex absolute section
1879 @item absolute section
1880 Address 0 of this section is always ``relocated'' to runtime address 0.
1881 This is useful if you want to refer to an address that @code{@value{LD}} must
1882 not change when relocating. In this sense we speak of absolute
1883 addresses being ``unrelocatable'': they do not change during relocation.
1885 @cindex undefined section
1886 @item undefined section
1887 This ``section'' is a catch-all for address references to objects not in
1888 the preceding sections.
1889 @c FIXME: ref to some other doc on obj-file formats could go here.
1892 @cindex relocation example
1893 An idealized example of three relocatable sections follows.
1895 The example uses the traditional section names @samp{.text} and @samp{.data}.
1897 Memory addresses are on the horizontal axis.
1901 @c END TEXI2ROFF-KILL
1904 partial program # 1: |ttttt|dddd|00|
1911 partial program # 2: |TTT|DDD|000|
1914 +--+---+-----+--+----+---+-----+~~
1915 linked program: | |TTT|ttttt| |dddd|DDD|00000|
1916 +--+---+-----+--+----+---+-----+~~
1918 addresses: 0 @dots{}
1925 \line{\it Partial program \#1: \hfil}
1926 \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
1927 \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
1929 \line{\it Partial program \#2: \hfil}
1930 \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
1931 \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
1933 \line{\it linked program: \hfil}
1934 \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
1935 \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
1936 ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
1937 DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
1939 \line{\it addresses: \hfil}
1943 @c END TEXI2ROFF-KILL
1946 @section @value{AS} Internal Sections
1948 @cindex internal @code{@value{AS}} sections
1949 @cindex sections in messages, internal
1950 These sections are meant only for the internal use of @code{@value{AS}}. They
1951 have no meaning at run-time. You do not really need to know about these
1952 sections for most purposes; but they can be mentioned in @code{@value{AS}}
1953 warning messages, so it might be helpful to have an idea of their
1954 meanings to @code{@value{AS}}. These sections are used to permit the
1955 value of every expression in your assembly language program to be a
1956 section-relative address.
1959 @item ASSEMBLER-INTERNAL-LOGIC-ERROR!
1960 @cindex assembler internal logic error
1961 An internal assembler logic error has been found. This means there is a
1962 bug in the assembler.
1965 @cindex expr (internal section)
1966 The assembler stores complex expression internally as combinations of
1967 symbols. When it needs to represent an expression as a symbol, it puts
1968 it in the expr section.
1970 @c FIXME item transfer[t] vector preload
1971 @c FIXME item transfer[t] vector postload
1972 @c FIXME item register
1976 @section Sub-Sections
1978 @cindex numbered subsections
1979 @cindex grouping data
1985 fall into two sections: text and data.
1987 You may have separate groups of
1989 data in named sections
1993 data in named sections
1999 that you want to end up near to each other in the object file, even though they
2000 are not contiguous in the assembler source. @code{@value{AS}} allows you to
2001 use @dfn{subsections} for this purpose. Within each section, there can be
2002 numbered subsections with values from 0 to 8192. Objects assembled into the
2003 same subsection go into the object file together with other objects in the same
2004 subsection. For example, a compiler might want to store constants in the text
2005 section, but might not want to have them interspersed with the program being
2006 assembled. In this case, the compiler could issue a @samp{.text 0} before each
2007 section of code being output, and a @samp{.text 1} before each group of
2008 constants being output.
2010 Subsections are optional. If you do not use subsections, everything
2011 goes in subsection number zero.
2014 Each subsection is zero-padded up to a multiple of four bytes.
2015 (Subsections may be padded a different amount on different flavors
2016 of @code{@value{AS}}.)
2020 On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word
2021 boundary (two bytes).
2022 The same is true on the Hitachi SH.
2025 @c FIXME section padding (alignment)?
2026 @c Rich Pixley says padding here depends on target obj code format; that
2027 @c doesn't seem particularly useful to say without further elaboration,
2028 @c so for now I say nothing about it. If this is a generic BFD issue,
2029 @c these paragraphs might need to vanish from this manual, and be
2030 @c discussed in BFD chapter of binutils (or some such).
2033 On the AMD 29K family, no particular padding is added to section or
2034 subsection sizes; @value{AS} forces no alignment on this platform.
2038 Subsections appear in your object file in numeric order, lowest numbered
2039 to highest. (All this to be compatible with other people's assemblers.)
2040 The object file contains no representation of subsections; @code{@value{LD}} and
2041 other programs that manipulate object files see no trace of them.
2042 They just see all your text subsections as a text section, and all your
2043 data subsections as a data section.
2045 To specify which subsection you want subsequent statements assembled
2046 into, use a numeric argument to specify it, in a @samp{.text
2047 @var{expression}} or a @samp{.data @var{expression}} statement.
2050 When generating COFF output, you
2055 can also use an extra subsection
2056 argument with arbitrary named sections: @samp{.section @var{name},
2059 @var{Expression} should be an absolute expression.
2060 (@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
2061 is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
2062 begins in @code{text 0}. For instance:
2064 .text 0 # The default subsection is text 0 anyway.
2065 .ascii "This lives in the first text subsection. *"
2067 .ascii "But this lives in the second text subsection."
2069 .ascii "This lives in the data section,"
2070 .ascii "in the first data subsection."
2072 .ascii "This lives in the first text section,"
2073 .ascii "immediately following the asterisk (*)."
2076 Each section has a @dfn{location counter} incremented by one for every byte
2077 assembled into that section. Because subsections are merely a convenience
2078 restricted to @code{@value{AS}} there is no concept of a subsection location
2079 counter. There is no way to directly manipulate a location counter---but the
2080 @code{.align} directive changes it, and any label definition captures its
2081 current value. The location counter of the section where statements are being
2082 assembled is said to be the @dfn{active} location counter.
2085 @section bss Section
2088 @cindex common variable storage
2089 The bss section is used for local common variable storage.
2090 You may allocate address space in the bss section, but you may
2091 not dictate data to load into it before your program executes. When
2092 your program starts running, all the contents of the bss
2093 section are zeroed bytes.
2095 Addresses in the bss section are allocated with special directives; you
2096 may not assemble anything directly into the bss section. Hence there
2097 are no bss subsections. @xref{Comm,,@code{.comm}},
2098 @pxref{Lcomm,,@code{.lcomm}}.
2104 Symbols are a central concept: the programmer uses symbols to name
2105 things, the linker uses symbols to link, and the debugger uses symbols
2109 @cindex debuggers, and symbol order
2110 @emph{Warning:} @code{@value{AS}} does not place symbols in the object file in
2111 the same order they were declared. This may break some debuggers.
2116 * Setting Symbols:: Giving Symbols Other Values
2117 * Symbol Names:: Symbol Names
2118 * Dot:: The Special Dot Symbol
2119 * Symbol Attributes:: Symbol Attributes
2126 A @dfn{label} is written as a symbol immediately followed by a colon
2127 @samp{:}. The symbol then represents the current value of the
2128 active location counter, and is, for example, a suitable instruction
2129 operand. You are warned if you use the same symbol to represent two
2130 different locations: the first definition overrides any other
2134 On the HPPA, the usual form for a label need not be immediately followed by a
2135 colon, but instead must start in column zero. Only one label may be defined on
2136 a single line. To work around this, the HPPA version of @code{@value{AS}} also
2137 provides a special directive @code{.label} for defining labels more flexibly.
2140 @node Setting Symbols
2141 @section Giving Symbols Other Values
2143 @cindex assigning values to symbols
2144 @cindex symbol values, assigning
2145 A symbol can be given an arbitrary value by writing a symbol, followed
2146 by an equals sign @samp{=}, followed by an expression
2147 (@pxref{Expressions}). This is equivalent to using the @code{.set}
2148 directive. @xref{Set,,@code{.set}}.
2151 @section Symbol Names
2153 @cindex symbol names
2154 @cindex names, symbol
2155 @ifclear SPECIAL-SYMS
2156 Symbol names begin with a letter or with one of @samp{._}. On most
2157 machines, you can also use @code{$} in symbol names; exceptions are
2158 noted in @ref{Machine Dependencies}. That character may be followed by any
2159 string of digits, letters, dollar signs (unless otherwise noted in
2160 @ref{Machine Dependencies}), and underscores.
2163 For the AMD 29K family, @samp{?} is also allowed in the
2164 body of a symbol name, though not at its beginning.
2169 Symbol names begin with a letter or with one of @samp{._}. On the
2171 H8/500, you can also use @code{$} in symbol names. That character may
2172 be followed by any string of digits, letters, dollar signs (save on the
2173 H8/300), and underscores.
2177 Case of letters is significant: @code{foo} is a different symbol name
2180 Each symbol has exactly one name. Each name in an assembly language program
2181 refers to exactly one symbol. You may use that symbol name any number of times
2184 @subheading Local Symbol Names
2186 @cindex local symbol names
2187 @cindex symbol names, local
2188 @cindex temporary symbol names
2189 @cindex symbol names, temporary
2190 Local symbols help compilers and programmers use names temporarily.
2191 There are ten local symbol names, which are re-used throughout the
2192 program. You may refer to them using the names @samp{0} @samp{1}
2193 @dots{} @samp{9}. To define a local symbol, write a label of the form
2194 @samp{@b{N}:} (where @b{N} represents any digit). To refer to the most
2195 recent previous definition of that symbol write @samp{@b{N}b}, using the
2196 same digit as when you defined the label. To refer to the next
2197 definition of a local label, write @samp{@b{N}f}---where @b{N} gives you
2198 a choice of 10 forward references. The @samp{b} stands for
2199 ``backwards'' and the @samp{f} stands for ``forwards''.
2201 Local symbols are not emitted by the current @sc{gnu} C compiler.
2203 There is no restriction on how you can use these labels, but
2204 remember that at any point in the assembly you can refer to at most
2205 10 prior local labels and to at most 10 forward local labels.
2207 Local symbol names are only a notation device. They are immediately
2208 transformed into more conventional symbol names before the assembler
2209 uses them. The symbol names stored in the symbol table, appearing in
2210 error messages and optionally emitted to the object file have these
2215 All local labels begin with @samp{L}. Normally both @code{@value{AS}} and
2216 @code{@value{LD}} forget symbols that start with @samp{L}. These labels are
2217 used for symbols you are never intended to see. If you use the
2218 @samp{-L} option then @code{@value{AS}} retains these symbols in the
2219 object file. If you also instruct @code{@value{LD}} to retain these symbols,
2220 you may use them in debugging.
2223 If the label is written @samp{0:} then the digit is @samp{0}.
2224 If the label is written @samp{1:} then the digit is @samp{1}.
2225 And so on up through @samp{9:}.
2228 This unusual character is included so you do not accidentally invent
2229 a symbol of the same name. The character has ASCII value
2232 @item @emph{ordinal number}
2233 This is a serial number to keep the labels distinct. The first
2234 @samp{0:} gets the number @samp{1}; The 15th @samp{0:} gets the
2235 number @samp{15}; @emph{etc.}. Likewise for the other labels @samp{1:}
2239 For instance, the first @code{1:} is named @code{L1@ctrl{A}1}, the 44th
2240 @code{3:} is named @code{L3@ctrl{A}44}.
2243 @section The Special Dot Symbol
2245 @cindex dot (symbol)
2246 @cindex @code{.} (symbol)
2247 @cindex current address
2248 @cindex location counter
2249 The special symbol @samp{.} refers to the current address that
2250 @code{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
2251 .long .} defines @code{melvin} to contain its own address.
2252 Assigning a value to @code{.} is treated the same as a @code{.org}
2253 directive. Thus, the expression @samp{.=.+4} is the same as saying
2254 @ifclear no-space-dir
2263 @node Symbol Attributes
2264 @section Symbol Attributes
2266 @cindex symbol attributes
2267 @cindex attributes, symbol
2268 Every symbol has, as well as its name, the attributes ``Value'' and
2269 ``Type''. Depending on output format, symbols can also have auxiliary
2272 The detailed definitions are in @file{a.out.h}.
2275 If you use a symbol without defining it, @code{@value{AS}} assumes zero for
2276 all these attributes, and probably won't warn you. This makes the
2277 symbol an externally defined symbol, which is generally what you
2281 * Symbol Value:: Value
2282 * Symbol Type:: Type
2285 * a.out Symbols:: Symbol Attributes: @code{a.out}
2289 * a.out Symbols:: Symbol Attributes: @code{a.out}
2292 * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
2297 * COFF Symbols:: Symbol Attributes for COFF
2300 * SOM Symbols:: Symbol Attributes for SOM
2307 @cindex value of a symbol
2308 @cindex symbol value
2309 The value of a symbol is (usually) 32 bits. For a symbol which labels a
2310 location in the text, data, bss or absolute sections the value is the
2311 number of addresses from the start of that section to the label.
2312 Naturally for text, data and bss sections the value of a symbol changes
2313 as @code{@value{LD}} changes section base addresses during linking. Absolute
2314 symbols' values do not change during linking: that is why they are
2317 The value of an undefined symbol is treated in a special way. If it is
2318 0 then the symbol is not defined in this assembler source file, and
2319 @code{@value{LD}} tries to determine its value from other files linked into the
2320 same program. You make this kind of symbol simply by mentioning a symbol
2321 name without defining it. A non-zero value represents a @code{.comm}
2322 common declaration. The value is how much common storage to reserve, in
2323 bytes (addresses). The symbol refers to the first address of the
2329 @cindex type of a symbol
2331 The type attribute of a symbol contains relocation (section)
2332 information, any flag settings indicating that a symbol is external, and
2333 (optionally), other information for linkers and debuggers. The exact
2334 format depends on the object-code output format in use.
2339 @c The following avoids a "widow" subsection title. @group would be
2340 @c better if it were available outside examples.
2343 @subsection Symbol Attributes: @code{a.out}, @code{b.out}
2345 @cindex @code{b.out} symbol attributes
2346 @cindex symbol attributes, @code{b.out}
2347 These symbol attributes appear only when @code{@value{AS}} is configured for
2348 one of the Berkeley-descended object output formats---@code{a.out} or
2354 @subsection Symbol Attributes: @code{a.out}
2356 @cindex @code{a.out} symbol attributes
2357 @cindex symbol attributes, @code{a.out}
2363 @subsection Symbol Attributes: @code{a.out}
2365 @cindex @code{a.out} symbol attributes
2366 @cindex symbol attributes, @code{a.out}
2370 * Symbol Desc:: Descriptor
2371 * Symbol Other:: Other
2375 @subsubsection Descriptor
2377 @cindex descriptor, of @code{a.out} symbol
2378 This is an arbitrary 16-bit value. You may establish a symbol's
2379 descriptor value by using a @code{.desc} statement
2380 (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
2384 @subsubsection Other
2386 @cindex other attribute, of @code{a.out} symbol
2387 This is an arbitrary 8-bit value. It means nothing to @code{@value{AS}}.
2392 @subsection Symbol Attributes for COFF
2394 @cindex COFF symbol attributes
2395 @cindex symbol attributes, COFF
2397 The COFF format supports a multitude of auxiliary symbol attributes;
2398 like the primary symbol attributes, they are set between @code{.def} and
2399 @code{.endef} directives.
2401 @subsubsection Primary Attributes
2403 @cindex primary attributes, COFF symbols
2404 The symbol name is set with @code{.def}; the value and type,
2405 respectively, with @code{.val} and @code{.type}.
2407 @subsubsection Auxiliary Attributes
2409 @cindex auxiliary attributes, COFF symbols
2410 The @code{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
2411 @code{.size}, and @code{.tag} can generate auxiliary symbol table
2412 information for COFF.
2417 @subsection Symbol Attributes for SOM
2419 @cindex SOM symbol attributes
2420 @cindex symbol attributes, SOM
2422 The SOM format for the HPPA supports a multitude of symbol attributes set with
2423 the @code{.EXPORT} and @code{.IMPORT} directives.
2425 The attributes are described in @cite{HP9000 Series 800 Assembly
2426 Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
2427 @code{EXPORT} assembler directive documentation.
2431 @chapter Expressions
2435 @cindex numeric values
2436 An @dfn{expression} specifies an address or numeric value.
2437 Whitespace may precede and/or follow an expression.
2439 The result of an expression must be an absolute number, or else an offset into
2440 a particular section. If an expression is not absolute, and there is not
2441 enough information when @code{@value{AS}} sees the expression to know its
2442 section, a second pass over the source program might be necessary to interpret
2443 the expression---but the second pass is currently not implemented.
2444 @code{@value{AS}} aborts with an error message in this situation.
2447 * Empty Exprs:: Empty Expressions
2448 * Integer Exprs:: Integer Expressions
2452 @section Empty Expressions
2454 @cindex empty expressions
2455 @cindex expressions, empty
2456 An empty expression has no value: it is just whitespace or null.
2457 Wherever an absolute expression is required, you may omit the
2458 expression, and @code{@value{AS}} assumes a value of (absolute) 0. This
2459 is compatible with other assemblers.
2462 @section Integer Expressions
2464 @cindex integer expressions
2465 @cindex expressions, integer
2466 An @dfn{integer expression} is one or more @emph{arguments} delimited
2467 by @emph{operators}.
2470 * Arguments:: Arguments
2471 * Operators:: Operators
2472 * Prefix Ops:: Prefix Operators
2473 * Infix Ops:: Infix Operators
2477 @subsection Arguments
2479 @cindex expression arguments
2480 @cindex arguments in expressions
2481 @cindex operands in expressions
2482 @cindex arithmetic operands
2483 @dfn{Arguments} are symbols, numbers or subexpressions. In other
2484 contexts arguments are sometimes called ``arithmetic operands''. In
2485 this manual, to avoid confusing them with the ``instruction operands'' of
2486 the machine language, we use the term ``argument'' to refer to parts of
2487 expressions only, reserving the word ``operand'' to refer only to machine
2488 instruction operands.
2490 Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
2491 @var{section} is one of text, data, bss, absolute,
2492 or undefined. @var{NNN} is a signed, 2's complement 32 bit
2495 Numbers are usually integers.
2497 A number can be a flonum or bignum. In this case, you are warned
2498 that only the low order 32 bits are used, and @code{@value{AS}} pretends
2499 these 32 bits are an integer. You may write integer-manipulating
2500 instructions that act on exotic constants, compatible with other
2503 @cindex subexpressions
2504 Subexpressions are a left parenthesis @samp{(} followed by an integer
2505 expression, followed by a right parenthesis @samp{)}; or a prefix
2506 operator followed by an argument.
2509 @subsection Operators
2511 @cindex operators, in expressions
2512 @cindex arithmetic functions
2513 @cindex functions, in expressions
2514 @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
2515 operators are followed by an argument. Infix operators appear
2516 between their arguments. Operators may be preceded and/or followed by
2520 @subsection Prefix Operator
2522 @cindex prefix operators
2523 @code{@value{AS}} has the following @dfn{prefix operators}. They each take
2524 one argument, which must be absolute.
2526 @c the tex/end tex stuff surrounding this small table is meant to make
2527 @c it align, on the printed page, with the similar table in the next
2528 @c section (which is inside an enumerate).
2530 \global\advance\leftskip by \itemindent
2535 @dfn{Negation}. Two's complement negation.
2537 @dfn{Complementation}. Bitwise not.
2541 \global\advance\leftskip by -\itemindent
2545 @subsection Infix Operators
2547 @cindex infix operators
2548 @cindex operators, permitted arguments
2549 @dfn{Infix operators} take two arguments, one on either side. Operators
2550 have precedence, but operations with equal precedence are performed left
2551 to right. Apart from @code{+} or @code{-}, both arguments must be
2552 absolute, and the result is absolute.
2555 @cindex operator precedence
2556 @cindex precedence of operators
2563 @dfn{Multiplication}.
2566 @dfn{Division}. Truncation is the same as the C operator @samp{/}
2573 @dfn{Shift Left}. Same as the C operator @samp{<<}.
2577 @dfn{Shift Right}. Same as the C operator @samp{>>}.
2581 Intermediate precedence
2586 @dfn{Bitwise Inclusive Or}.
2592 @dfn{Bitwise Exclusive Or}.
2595 @dfn{Bitwise Or Not}.
2603 @cindex addition, permitted arguments
2604 @cindex plus, permitted arguments
2605 @cindex arguments for addition
2606 @dfn{Addition}. If either argument is absolute, the result has the section of
2607 the other argument. You may not add together arguments from different
2611 @cindex subtraction, permitted arguments
2612 @cindex minus, permitted arguments
2613 @cindex arguments for subtraction
2614 @dfn{Subtraction}. If the right argument is absolute, the
2615 result has the section of the left argument.
2616 If both arguments are in the same section, the result is absolute.
2617 You may not subtract arguments from different sections.
2618 @c FIXME is there still something useful to say about undefined - undefined ?
2622 In short, it's only meaningful to add or subtract the @emph{offsets} in an
2623 address; you can only have a defined section in one of the two arguments.
2626 @chapter Assembler Directives
2628 @cindex directives, machine independent
2629 @cindex pseudo-ops, machine independent
2630 @cindex machine independent directives
2631 All assembler directives have names that begin with a period (@samp{.}).
2632 The rest of the name is letters, usually in lower case.
2634 This chapter discusses directives that are available regardless of the
2635 target machine configuration for the @sc{gnu} assembler.
2637 Some machine configurations provide additional directives.
2638 @xref{Machine Dependencies}.
2641 @ifset machine-directives
2642 @xref{Machine Dependencies} for additional directives.
2647 * Abort:: @code{.abort}
2649 * ABORT:: @code{.ABORT}
2652 * Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
2653 * App-File:: @code{.app-file @var{string}}
2654 * Ascii:: @code{.ascii "@var{string}"}@dots{}
2655 * Asciz:: @code{.asciz "@var{string}"}@dots{}
2656 * Byte:: @code{.byte @var{expressions}}
2657 * Comm:: @code{.comm @var{symbol} , @var{length} }
2658 * Data:: @code{.data @var{subsection}}
2660 * Def:: @code{.def @var{name}}
2663 * Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
2669 * Double:: @code{.double @var{flonums}}
2670 * Eject:: @code{.eject}
2671 * Else:: @code{.else}
2673 * Endef:: @code{.endef}
2676 * Endif:: @code{.endif}
2677 * Equ:: @code{.equ @var{symbol}, @var{expression}}
2678 * Extern:: @code{.extern}
2679 @ifclear no-file-dir
2680 * File:: @code{.file @var{string}}
2683 * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
2684 * Float:: @code{.float @var{flonums}}
2685 * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
2686 * hword:: @code{.hword @var{expressions}}
2687 * Ident:: @code{.ident}
2688 * If:: @code{.if @var{absolute expression}}
2689 * Include:: @code{.include "@var{file}"}
2690 * Int:: @code{.int @var{expressions}}
2691 * Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
2692 * Lflags:: @code{.lflags}
2693 @ifclear no-line-dir
2694 * Line:: @code{.line @var{line-number}}
2697 * Ln:: @code{.ln @var{line-number}}
2698 * List:: @code{.list}
2699 * Long:: @code{.long @var{expressions}}
2701 * Lsym:: @code{.lsym @var{symbol}, @var{expression}}
2704 * Nolist:: @code{.nolist}
2705 * Octa:: @code{.octa @var{bignums}}
2706 * Org:: @code{.org @var{new-lc} , @var{fill}}
2707 * Psize:: @code{.psize @var{lines}, @var{columns}}
2708 * Quad:: @code{.quad @var{bignums}}
2709 * Sbttl:: @code{.sbttl "@var{subheading}"}
2711 * Scl:: @code{.scl @var{class}}
2714 * Section:: @code{.section @var{name}, @var{subsection}}
2717 * Set:: @code{.set @var{symbol}, @var{expression}}
2718 * Short:: @code{.short @var{expressions}}
2719 * Single:: @code{.single @var{flonums}}
2721 * Size:: @code{.size}
2724 * Space:: @code{.space @var{size} , @var{fill}}
2726 * Stab:: @code{.stabd, .stabn, .stabs}
2729 * String:: @code{.string "@var{str}"}
2731 * Tag:: @code{.tag @var{structname}}
2734 * Text:: @code{.text @var{subsection}}
2735 * Title:: @code{.title "@var{heading}"}
2737 * Type:: @code{.type @var{int}}
2738 * Val:: @code{.val @var{addr}}
2741 * Word:: @code{.word @var{expressions}}
2742 * Deprecated:: Deprecated Directives
2746 @section @code{.abort}
2748 @cindex @code{abort} directive
2749 @cindex stopping the assembly
2750 This directive stops the assembly immediately. It is for
2751 compatibility with other assemblers. The original idea was that the
2752 assembly language source would be piped into the assembler. If the sender
2753 of the source quit, it could use this directive tells @code{@value{AS}} to
2754 quit also. One day @code{.abort} will not be supported.
2758 @section @code{.ABORT}
2760 @cindex @code{ABORT} directive
2761 When producing COFF output, @code{@value{AS}} accepts this directive as a
2762 synonym for @samp{.abort}.
2765 When producing @code{b.out} output, @code{@value{AS}} accepts this directive,
2771 @section @code{.align @var{abs-expr} , @var{abs-expr}}
2773 @cindex padding the location counter
2774 @cindex @code{align} directive
2775 Pad the location counter (in the current subsection) to a particular
2776 storage boundary. The first expression (which must be absolute) is the
2777 number of low-order zero bits the location counter must have after
2778 advancement. For example @samp{.align 3} advances the location
2779 counter until it a multiple of 8. If the location counter is already a
2780 multiple of 8, no change is needed.
2783 For the HPPA, the first expression (which must be absolute) is the
2784 alignment request in bytes. For example @samp{.align 8} advances
2785 the location counter until it is a multiple of 8. If the location counter
2786 is already a multiple of 8, no change is needed.
2789 The second expression (also absolute) gives the value to be stored in
2790 the padding bytes. It (and the comma) may be omitted. If it is
2791 omitted, the padding bytes are zero.
2794 @section @code{.app-file @var{string}}
2796 @cindex logical file name
2797 @cindex file name, logical
2798 @cindex @code{app-file} directive
2800 @ifclear no-file-dir
2801 (which may also be spelled @samp{.file})
2803 tells @code{@value{AS}} that we are about to start a new
2804 logical file. @var{string} is the new file name. In general, the
2805 filename is recognized whether or not it is surrounded by quotes @samp{"};
2806 but if you wish to specify an empty file name is permitted,
2807 you must give the quotes--@code{""}. This statement may go away in
2808 future: it is only recognized to be compatible with old @code{@value{AS}}
2812 @section @code{.ascii "@var{string}"}@dots{}
2814 @cindex @code{ascii} directive
2815 @cindex string literals
2816 @code{.ascii} expects zero or more string literals (@pxref{Strings})
2817 separated by commas. It assembles each string (with no automatic
2818 trailing zero byte) into consecutive addresses.
2821 @section @code{.asciz "@var{string}"}@dots{}
2823 @cindex @code{asciz} directive
2824 @cindex zero-terminated strings
2825 @cindex null-terminated strings
2826 @code{.asciz} is just like @code{.ascii}, but each string is followed by
2827 a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
2830 @section @code{.byte @var{expressions}}
2832 @cindex @code{byte} directive
2833 @cindex integers, one byte
2834 @code{.byte} expects zero or more expressions, separated by commas.
2835 Each expression is assembled into the next byte.
2838 @section @code{.comm @var{symbol} , @var{length} }
2840 @cindex @code{comm} directive
2841 @cindex symbol, common
2842 @code{.comm} declares a named common area in the bss section. Normally
2843 @code{@value{LD}} reserves memory addresses for it during linking, so no partial
2844 program defines the location of the symbol. Use @code{.comm} to tell
2845 @code{@value{LD}} that it must be at least @var{length} bytes long. @code{@value{LD}}
2846 allocates space for each @code{.comm} symbol that is at least as
2847 long as the longest @code{.comm} request in any of the partial programs
2848 linked. @var{length} is an absolute expression.
2851 The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
2852 @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
2856 @section @code{.data @var{subsection}}
2858 @cindex @code{data} directive
2859 @code{.data} tells @code{@value{AS}} to assemble the following statements onto the
2860 end of the data subsection numbered @var{subsection} (which is an
2861 absolute expression). If @var{subsection} is omitted, it defaults
2866 @section @code{.def @var{name}}
2868 @cindex @code{def} directive
2869 @cindex COFF symbols, debugging
2870 @cindex debugging COFF symbols
2871 Begin defining debugging information for a symbol @var{name}; the
2872 definition extends until the @code{.endef} directive is encountered.
2875 This directive is only observed when @code{@value{AS}} is configured for COFF
2876 format output; when producing @code{b.out}, @samp{.def} is recognized,
2883 @section @code{.desc @var{symbol}, @var{abs-expression}}
2885 @cindex @code{desc} directive
2886 @cindex COFF symbol descriptor
2887 @cindex symbol descriptor, COFF
2888 This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
2889 to the low 16 bits of an absolute expression.
2892 The @samp{.desc} directive is not available when @code{@value{AS}} is
2893 configured for COFF output; it is only for @code{a.out} or @code{b.out}
2894 object format. For the sake of compatibility, @code{@value{AS}} accepts
2895 it, but produces no output, when configured for COFF.
2901 @section @code{.dim}
2903 @cindex @code{dim} directive
2904 @cindex COFF auxiliary symbol information
2905 @cindex auxiliary symbol information, COFF
2906 This directive is generated by compilers to include auxiliary debugging
2907 information in the symbol table. It is only permitted inside
2908 @code{.def}/@code{.endef} pairs.
2911 @samp{.dim} is only meaningful when generating COFF format output; when
2912 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
2918 @section @code{.double @var{flonums}}
2920 @cindex @code{double} directive
2921 @cindex floating point numbers (double)
2922 @code{.double} expects zero or more flonums, separated by commas. It
2923 assembles floating point numbers.
2925 The exact kind of floating point numbers emitted depends on how
2926 @code{@value{AS}} is configured. @xref{Machine Dependencies}.
2930 On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
2931 in @sc{ieee} format.
2936 @section @code{.eject}
2938 @cindex @code{eject} directive
2939 @cindex new page, in listings
2940 @cindex page, in listings
2941 @cindex listing control: new page
2942 Force a page break at this point, when generating assembly listings.
2945 @section @code{.else}
2947 @cindex @code{else} directive
2948 @code{.else} is part of the @code{@value{AS}} support for conditional
2949 assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
2950 of code to be assembled if the condition for the preceding @code{.if}
2954 @node End, Endef, Else, Pseudo Ops
2955 @section @code{.end}
2957 @cindex @code{end} directive
2958 This doesn't do anything---but isn't an s_ignore, so I suspect it's
2959 meant to do something eventually (which is why it isn't documented here
2960 as "for compatibility with blah").
2965 @section @code{.endef}
2967 @cindex @code{endef} directive
2968 This directive flags the end of a symbol definition begun with
2972 @samp{.endef} is only meaningful when generating COFF format output; if
2973 @code{@value{AS}} is configured to generate @code{b.out}, it accepts this
2974 directive but ignores it.
2979 @section @code{.endif}
2981 @cindex @code{endif} directive
2982 @code{.endif} is part of the @code{@value{AS}} support for conditional assembly;
2983 it marks the end of a block of code that is only assembled
2984 conditionally. @xref{If,,@code{.if}}.
2987 @section @code{.equ @var{symbol}, @var{expression}}
2989 @cindex @code{equ} directive
2990 @cindex assigning values to symbols
2991 @cindex symbols, assigning values to
2992 This directive sets the value of @var{symbol} to @var{expression}.
2993 It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
2996 The syntax for @code{equ} on the HPPA is
2997 @samp{@var{symbol} .equ @var{expression}}.
3001 @section @code{.extern}
3003 @cindex @code{extern} directive
3004 @code{.extern} is accepted in the source program---for compatibility
3005 with other assemblers---but it is ignored. @code{@value{AS}} treats
3006 all undefined symbols as external.
3008 @ifclear no-file-dir
3010 @section @code{.file @var{string}}
3012 @cindex @code{file} directive
3013 @cindex logical file name
3014 @cindex file name, logical
3015 @code{.file} (which may also be spelled @samp{.app-file}) tells
3016 @code{@value{AS}} that we are about to start a new logical file.
3017 @var{string} is the new file name. In general, the filename is
3018 recognized whether or not it is surrounded by quotes @samp{"}; but if
3019 you wish to specify an empty file name, you must give the
3020 quotes--@code{""}. This statement may go away in future: it is only
3021 recognized to be compatible with old @code{@value{AS}} programs.
3023 In some configurations of @code{@value{AS}}, @code{.file} has already been
3024 removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}.
3029 @section @code{.fill @var{repeat} , @var{size} , @var{value}}
3031 @cindex @code{fill} directive
3032 @cindex writing patterns in memory
3033 @cindex patterns, writing in memory
3034 @var{result}, @var{size} and @var{value} are absolute expressions.
3035 This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
3036 may be zero or more. @var{Size} may be zero or more, but if it is
3037 more than 8, then it is deemed to have the value 8, compatible with
3038 other people's assemblers. The contents of each @var{repeat} bytes
3039 is taken from an 8-byte number. The highest order 4 bytes are
3040 zero. The lowest order 4 bytes are @var{value} rendered in the
3041 byte-order of an integer on the computer @code{@value{AS}} is assembling for.
3042 Each @var{size} bytes in a repetition is taken from the lowest order
3043 @var{size} bytes of this number. Again, this bizarre behavior is
3044 compatible with other people's assemblers.
3046 @var{size} and @var{value} are optional.
3047 If the second comma and @var{value} are absent, @var{value} is
3048 assumed zero. If the first comma and following tokens are absent,
3049 @var{size} is assumed to be 1.
3052 @section @code{.float @var{flonums}}
3054 @cindex floating point numbers (single)
3055 @cindex @code{float} directive
3056 This directive assembles zero or more flonums, separated by commas. It
3057 has the same effect as @code{.single}.
3059 The exact kind of floating point numbers emitted depends on how
3060 @code{@value{AS}} is configured.
3061 @xref{Machine Dependencies}.
3065 On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
3066 in @sc{ieee} format.
3071 @section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
3073 @cindex @code{global} directive
3074 @cindex symbol, making visible to linker
3075 @code{.global} makes the symbol visible to @code{@value{LD}}. If you define
3076 @var{symbol} in your partial program, its value is made available to
3077 other partial programs that are linked with it. Otherwise,
3078 @var{symbol} takes its attributes from a symbol of the same name
3079 from another file linked into the same program.
3081 Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
3082 compatibility with other assemblers.
3085 On the HPPA, @code{.global} is not always enough to make it accessible to other
3086 partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
3087 @xref{HPPA Directives,, HPPA Assembler Directives}.
3091 @section @code{.hword @var{expressions}}
3093 @cindex @code{hword} directive
3094 @cindex integers, 16-bit
3095 @cindex numbers, 16-bit
3096 @cindex sixteen bit integers
3097 This expects zero or more @var{expressions}, and emits
3098 a 16 bit number for each.
3101 This directive is a synonym for @samp{.short}; depending on the target
3102 architecture, it may also be a synonym for @samp{.word}.
3106 This directive is a synonym for @samp{.short}.
3109 This directive is a synonym for both @samp{.short} and @samp{.word}.
3114 @section @code{.ident}
3116 @cindex @code{ident} directive
3117 This directive is used by some assemblers to place tags in object files.
3118 @code{@value{AS}} simply accepts the directive for source-file
3119 compatibility with such assemblers, but does not actually emit anything
3123 @section @code{.if @var{absolute expression}}
3125 @cindex conditional assembly
3126 @cindex @code{if} directive
3127 @code{.if} marks the beginning of a section of code which is only
3128 considered part of the source program being assembled if the argument
3129 (which must be an @var{absolute expression}) is non-zero. The end of
3130 the conditional section of code must be marked by @code{.endif}
3131 (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
3132 alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}.
3134 The following variants of @code{.if} are also supported:
3136 @item .ifdef @var{symbol}
3137 @cindex @code{ifdef} directive
3138 Assembles the following section of code if the specified @var{symbol}
3143 @cindex @code{ifeqs} directive
3144 Not yet implemented.
3147 @item .ifndef @var{symbol}
3148 @itemx ifnotdef @var{symbol}
3149 @cindex @code{ifndef} directive
3150 @cindex @code{ifnotdef} directive
3151 Assembles the following section of code if the specified @var{symbol}
3152 has not been defined. Both spelling variants are equivalent.
3156 Not yet implemented.
3161 @section @code{.include "@var{file}"}
3163 @cindex @code{include} directive
3164 @cindex supporting files, including
3165 @cindex files, including
3166 This directive provides a way to include supporting files at specified
3167 points in your source program. The code from @var{file} is assembled as
3168 if it followed the point of the @code{.include}; when the end of the
3169 included file is reached, assembly of the original file continues. You
3170 can control the search paths used with the @samp{-I} command-line option
3171 (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
3175 @section @code{.int @var{expressions}}
3177 @cindex @code{int} directive
3178 @cindex integers, 32-bit
3179 Expect zero or more @var{expressions}, of any section, separated by commas.
3180 For each expression, emit a number that, at run time, is the value of that
3181 expression. The byte order and bit size of the number depends on what kind
3182 of target the assembly is for.
3186 On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit
3187 integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits
3193 @section @code{.lcomm @var{symbol} , @var{length}}
3195 @cindex @code{lcomm} directive
3196 @cindex local common symbols
3197 @cindex symbols, local common
3198 Reserve @var{length} (an absolute expression) bytes for a local common
3199 denoted by @var{symbol}. The section and value of @var{symbol} are
3200 those of the new local common. The addresses are allocated in the bss
3201 section, so that at run-time the bytes start off zeroed. @var{Symbol}
3202 is not declared global (@pxref{Global,,@code{.global}}), so is normally
3203 not visible to @code{@value{LD}}.
3206 The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
3207 @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
3211 @section @code{.lflags}
3213 @cindex @code{lflags} directive (ignored)
3214 @code{@value{AS}} accepts this directive, for compatibility with other
3215 assemblers, but ignores it.
3217 @ifclear no-line-dir
3219 @section @code{.line @var{line-number}}
3221 @cindex @code{line} directive
3225 @section @code{.ln @var{line-number}}
3227 @cindex @code{ln} directive
3229 @cindex logical line number
3231 Change the logical line number. @var{line-number} must be an absolute
3232 expression. The next line has that logical line number. Therefore any other
3233 statements on the current line (after a statement separator character) are
3234 reported as on logical line number @var{line-number} @minus{} 1. One day
3235 @code{@value{AS}} will no longer support this directive: it is recognized only
3236 for compatibility with existing assembler programs.
3240 @emph{Warning:} In the AMD29K configuration of @value{AS}, this command is
3241 not available; use the synonym @code{.ln} in that context.
3246 @ifclear no-line-dir
3247 Even though this is a directive associated with the @code{a.out} or
3248 @code{b.out} object-code formats, @code{@value{AS}} still recognizes it
3249 when producing COFF output, and treats @samp{.line} as though it
3250 were the COFF @samp{.ln} @emph{if} it is found outside a
3251 @code{.def}/@code{.endef} pair.
3253 Inside a @code{.def}, @samp{.line} is, instead, one of the directives
3254 used by compilers to generate auxiliary symbol information for
3259 @section @code{.ln @var{line-number}}
3261 @cindex @code{ln} directive
3262 @ifclear no-line-dir
3263 @samp{.ln} is a synonym for @samp{.line}.
3266 Tell @code{@value{AS}} to change the logical line number. @var{line-number}
3267 must be an absolute expression. The next line has that logical
3268 line number, so any other statements on the current line (after a
3269 statement separator character @code{;}) are reported as on logical
3270 line number @var{line-number} @minus{} 1.
3273 This directive is accepted, but ignored, when @code{@value{AS}} is
3274 configured for @code{b.out}; its effect is only associated with COFF
3280 @section @code{.list}
3282 @cindex @code{list} directive
3283 @cindex listing control, turning on
3284 Control (in conjunction with the @code{.nolist} directive) whether or
3285 not assembly listings are generated. These two directives maintain an
3286 internal counter (which is zero initially). @code{.list} increments the
3287 counter, and @code{.nolist} decrements it. Assembly listings are
3288 generated whenever the counter is greater than zero.
3290 By default, listings are disabled. When you enable them (with the
3291 @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
3292 the initial value of the listing counter is one.
3295 @section @code{.long @var{expressions}}
3297 @cindex @code{long} directive
3298 @code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
3301 @c no one seems to know what this is for or whether this description is
3302 @c what it really ought to do
3304 @section @code{.lsym @var{symbol}, @var{expression}}
3306 @cindex @code{lsym} directive
3307 @cindex symbol, not referenced in assembly
3308 @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
3309 the hash table, ensuring it cannot be referenced by name during the
3310 rest of the assembly. This sets the attributes of the symbol to be
3311 the same as the expression value:
3313 @var{other} = @var{descriptor} = 0
3314 @var{type} = @r{(section of @var{expression})}
3315 @var{value} = @var{expression}
3318 The new symbol is not flagged as external.
3322 @section @code{.nolist}
3324 @cindex @code{nolist} directive
3325 @cindex listing control, turning off
3326 Control (in conjunction with the @code{.list} directive) whether or
3327 not assembly listings are generated. These two directives maintain an
3328 internal counter (which is zero initially). @code{.list} increments the
3329 counter, and @code{.nolist} decrements it. Assembly listings are
3330 generated whenever the counter is greater than zero.
3333 @section @code{.octa @var{bignums}}
3335 @c FIXME: double size emitted for "octa" on i960, others? Or warn?
3336 @cindex @code{octa} directive
3337 @cindex integer, 16-byte
3338 @cindex sixteen byte integer
3339 This directive expects zero or more bignums, separated by commas. For each
3340 bignum, it emits a 16-byte integer.
3342 The term ``octa'' comes from contexts in which a ``word'' is two bytes;
3343 hence @emph{octa}-word for 16 bytes.
3346 @section @code{.org @var{new-lc} , @var{fill}}
3348 @cindex @code{org} directive
3349 @cindex location counter, advancing
3350 @cindex advancing location counter
3351 @cindex current address, advancing
3352 Advance the location counter of the current section to
3353 @var{new-lc}. @var{new-lc} is either an absolute expression or an
3354 expression with the same section as the current subsection. That is,
3355 you can't use @code{.org} to cross sections: if @var{new-lc} has the
3356 wrong section, the @code{.org} directive is ignored. To be compatible
3357 with former assemblers, if the section of @var{new-lc} is absolute,
3358 @code{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
3359 is the same as the current subsection.
3361 @code{.org} may only increase the location counter, or leave it
3362 unchanged; you cannot use @code{.org} to move the location counter
3365 @c double negative used below "not undefined" because this is a specific
3366 @c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
3367 @c section. pesch@cygnus.com 18feb91
3368 Because @code{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
3369 may not be undefined. If you really detest this restriction we eagerly await
3370 a chance to share your improved assembler.
3372 Beware that the origin is relative to the start of the section, not
3373 to the start of the subsection. This is compatible with other
3374 people's assemblers.
3376 When the location counter (of the current subsection) is advanced, the
3377 intervening bytes are filled with @var{fill} which should be an
3378 absolute expression. If the comma and @var{fill} are omitted,
3379 @var{fill} defaults to zero.
3382 @section @code{.psize @var{lines} , @var{columns}}
3384 @cindex @code{psize} directive
3385 @cindex listing control: paper size
3386 @cindex paper size, for listings
3387 Use this directive to declare the number of lines---and, optionally, the
3388 number of columns---to use for each page, when generating listings.
3390 If you do not use @code{.psize}, listings use a default line-count
3391 of 60. You may omit the comma and @var{columns} specification; the
3392 default width is 200 columns.
3394 @code{@value{AS}} generates formfeeds whenever the specified number of
3395 lines is exceeded (or whenever you explicitly request one, using
3398 If you specify @var{lines} as @code{0}, no formfeeds are generated save
3399 those explicitly specified with @code{.eject}.
3402 @section @code{.quad @var{bignums}}
3404 @cindex @code{quad} directive
3405 @code{.quad} expects zero or more bignums, separated by commas. For
3406 each bignum, it emits
3408 an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
3409 warning message; and just takes the lowest order 8 bytes of the bignum.
3410 @cindex eight-byte integer
3411 @cindex integer, 8-byte
3413 The term ``quad'' comes from contexts in which a ``word'' is two bytes;
3414 hence @emph{quad}-word for 8 bytes.
3417 a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
3418 warning message; and just takes the lowest order 16 bytes of the bignum.
3419 @cindex sixteen-byte integer
3420 @cindex integer, 16-byte
3424 @section @code{.sbttl "@var{subheading}"}
3426 @cindex @code{sbttl} directive
3427 @cindex subtitles for listings
3428 @cindex listing control: subtitle
3429 Use @var{subheading} as the title (third line, immediately after the
3430 title line) when generating assembly listings.
3432 This directive affects subsequent pages, as well as the current page if
3433 it appears within ten lines of the top of a page.
3437 @section @code{.scl @var{class}}
3439 @cindex @code{scl} directive
3440 @cindex symbol storage class (COFF)
3441 @cindex COFF symbol storage class
3442 Set the storage-class value for a symbol. This directive may only be
3443 used inside a @code{.def}/@code{.endef} pair. Storage class may flag
3444 whether a symbol is static or external, or it may record further
3445 symbolic debugging information.
3448 The @samp{.scl} directive is primarily associated with COFF output; when
3449 configured to generate @code{b.out} output format, @code{@value{AS}}
3450 accepts this directive but ignores it.
3456 @section @code{.section @var{name}, @var{subsection}}
3458 @cindex @code{section} directive
3459 @cindex named section (COFF)
3460 @cindex COFF named section
3461 Assemble the following code into end of subsection numbered
3462 @var{subsection} in the COFF named section @var{name}. If you omit
3463 @var{subsection}, @code{@value{AS}} uses subsection number zero.
3464 @samp{.section .text} is equivalent to the @code{.text} directive;
3465 @samp{.section .data} is equivalent to the @code{.data} directive.
3467 This directive is only supported for targets that actually support arbitrarily
3468 named sections; on @code{a.out} targets, for example, it is not accepted, even
3469 with a standard @code{a.out} section name as its parameter.
3474 @section @code{.set @var{symbol}, @var{expression}}
3476 @cindex @code{set} directive
3477 @cindex symbol value, setting
3478 Set the value of @var{symbol} to @var{expression}. This
3479 changes @var{symbol}'s value and type to conform to
3480 @var{expression}. If @var{symbol} was flagged as external, it remains
3481 flagged. (@xref{Symbol Attributes}.)
3483 You may @code{.set} a symbol many times in the same assembly.
3485 If you @code{.set} a global symbol, the value stored in the object
3486 file is the last value stored into it.
3489 The syntax for @code{set} on the HPPA is
3490 @samp{@var{symbol} .set @var{expression}}.
3494 @section @code{.short @var{expressions}}
3496 @cindex @code{short} directive
3498 @code{.short} is normally the same as @samp{.word}.
3499 @xref{Word,,@code{.word}}.
3501 In some configurations, however, @code{.short} and @code{.word} generate
3502 numbers of different lengths; @pxref{Machine Dependencies}.
3506 @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
3509 This expects zero or more @var{expressions}, and emits
3510 a 16 bit number for each.
3515 @section @code{.single @var{flonums}}
3517 @cindex @code{single} directive
3518 @cindex floating point numbers (single)
3519 This directive assembles zero or more flonums, separated by commas. It
3520 has the same effect as @code{.float}.
3522 The exact kind of floating point numbers emitted depends on how
3523 @code{@value{AS}} is configured. @xref{Machine Dependencies}.
3527 On the @value{TARGET} family, @code{.single} emits 32-bit floating point
3528 numbers in @sc{ieee} format.
3534 @section @code{.size}
3536 @cindex @code{size} directive
3537 This directive is generated by compilers to include auxiliary debugging
3538 information in the symbol table. It is only permitted inside
3539 @code{.def}/@code{.endef} pairs.
3542 @samp{.size} is only meaningful when generating COFF format output; when
3543 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
3548 @ifclear no-space-dir
3550 @section @code{.space @var{size} , @var{fill}}
3552 @cindex @code{space} directive
3553 @cindex filling memory
3554 This directive emits @var{size} bytes, each of value @var{fill}. Both
3555 @var{size} and @var{fill} are absolute expressions. If the comma
3556 and @var{fill} are omitted, @var{fill} is assumed to be zero.
3560 @emph{Warning:} @code{.space} has a completely different meaning for HPPA
3561 targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
3562 Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
3563 @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
3572 @section @code{.space}
3573 @cindex @code{space} directive
3575 On the AMD 29K, this directive is ignored; it is accepted for
3576 compatibility with other AMD 29K assemblers.
3579 @emph{Warning:} In most versions of the @sc{gnu} assembler, the directive
3580 @code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
3586 @section @code{.stabd, .stabn, .stabs}
3588 @cindex symbolic debuggers, information for
3589 @cindex @code{stab@var{x}} directives
3590 There are three directives that begin @samp{.stab}.
3591 All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
3592 The symbols are not entered in the @code{@value{AS}} hash table: they
3593 cannot be referenced elsewhere in the source file.
3594 Up to five fields are required:
3598 This is the symbol's name. It may contain any character except
3599 @samp{\000}, so is more general than ordinary symbol names. Some
3600 debuggers used to code arbitrarily complex structures into symbol names
3604 An absolute expression. The symbol's type is set to the low 8 bits of
3605 this expression. Any bit pattern is permitted, but @code{@value{LD}}
3606 and debuggers choke on silly bit patterns.
3609 An absolute expression. The symbol's ``other'' attribute is set to the
3610 low 8 bits of this expression.
3613 An absolute expression. The symbol's descriptor is set to the low 16
3614 bits of this expression.
3617 An absolute expression which becomes the symbol's value.
3620 If a warning is detected while reading a @code{.stabd}, @code{.stabn},
3621 or @code{.stabs} statement, the symbol has probably already been created;
3622 you get a half-formed symbol in your object file. This is
3623 compatible with earlier assemblers!
3626 @cindex @code{stabd} directive
3627 @item .stabd @var{type} , @var{other} , @var{desc}
3629 The ``name'' of the symbol generated is not even an empty string.
3630 It is a null pointer, for compatibility. Older assemblers used a
3631 null pointer so they didn't waste space in object files with empty
3634 The symbol's value is set to the location counter,
3635 relocatably. When your program is linked, the value of this symbol
3636 is the address of the location counter when the @code{.stabd} was
3639 @item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
3640 @cindex @code{stabn} directive
3641 The name of the symbol is set to the empty string @code{""}.
3643 @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
3644 @cindex @code{stabs} directive
3645 All five fields are specified.
3651 @section @code{.string} "@var{str}"
3653 @cindex string, copying to object file
3654 @cindex @code{string} directive
3656 Copy the characters in @var{str} to the object file. You may specify more than
3657 one string to copy, separated by commas. Unless otherwise specified for a
3658 particular machine, the assembler marks the end of each string with a 0 byte.
3659 You can use any of the escape sequences described in @ref{Strings,,Strings}.
3663 @section @code{.tag @var{structname}}
3665 @cindex COFF structure debugging
3666 @cindex structure debugging, COFF
3667 @cindex @code{tag} directive
3668 This directive is generated by compilers to include auxiliary debugging
3669 information in the symbol table. It is only permitted inside
3670 @code{.def}/@code{.endef} pairs. Tags are used to link structure
3671 definitions in the symbol table with instances of those structures.
3674 @samp{.tag} is only used when generating COFF format output; when
3675 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
3681 @section @code{.text @var{subsection}}
3683 @cindex @code{text} directive
3684 Tells @code{@value{AS}} to assemble the following statements onto the end of
3685 the text subsection numbered @var{subsection}, which is an absolute
3686 expression. If @var{subsection} is omitted, subsection number zero
3690 @section @code{.title "@var{heading}"}
3692 @cindex @code{title} directive
3693 @cindex listing control: title line
3694 Use @var{heading} as the title (second line, immediately after the
3695 source file name and pagenumber) when generating assembly listings.
3697 This directive affects subsequent pages, as well as the current page if
3698 it appears within ten lines of the top of a page.
3702 @section @code{.type @var{int}}
3704 @cindex COFF symbol type
3705 @cindex symbol type, COFF
3706 @cindex @code{type} directive
3707 This directive, permitted only within @code{.def}/@code{.endef} pairs,
3708 records the integer @var{int} as the type attribute of a symbol table entry.
3711 @samp{.type} is associated only with COFF format output; when
3712 @code{@value{AS}} is configured for @code{b.out} output, it accepts this
3713 directive but ignores it.
3719 @section @code{.val @var{addr}}
3721 @cindex @code{val} directive
3722 @cindex COFF value attribute
3723 @cindex value attribute, COFF
3724 This directive, permitted only within @code{.def}/@code{.endef} pairs,
3725 records the address @var{addr} as the value attribute of a symbol table
3729 @samp{.val} is used only for COFF output; when @code{@value{AS}} is
3730 configured for @code{b.out}, it accepts this directive but ignores it.
3735 @section @code{.word @var{expressions}}
3737 @cindex @code{word} directive
3738 This directive expects zero or more @var{expressions}, of any section,
3739 separated by commas.
3742 For each expression, @code{@value{AS}} emits a 32-bit number.
3745 For each expression, @code{@value{AS}} emits a 16-bit number.
3750 The size of the number emitted, and its byte order,
3751 depend on what target computer the assembly is for.
3754 @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
3755 @c happen---32-bit addressability, period; no long/short jumps.
3756 @ifset DIFF-TBL-KLUGE
3757 @cindex difference tables altered
3758 @cindex altered difference tables
3760 @emph{Warning: Special Treatment to support Compilers}
3764 Machines with a 32-bit address space, but that do less than 32-bit
3765 addressing, require the following special treatment. If the machine of
3766 interest to you does 32-bit addressing (or doesn't require it;
3767 @pxref{Machine Dependencies}), you can ignore this issue.
3770 In order to assemble compiler output into something that works,
3771 @code{@value{AS}} occasionlly does strange things to @samp{.word} directives.
3772 Directives of the form @samp{.word sym1-sym2} are often emitted by
3773 compilers as part of jump tables. Therefore, when @code{@value{AS}} assembles a
3774 directive of the form @samp{.word sym1-sym2}, and the difference between
3775 @code{sym1} and @code{sym2} does not fit in 16 bits, @code{@value{AS}}
3776 creates a @dfn{secondary jump table}, immediately before the next label.
3777 This secondary jump table is preceded by a short-jump to the
3778 first byte after the secondary table. This short-jump prevents the flow
3779 of control from accidentally falling into the new table. Inside the
3780 table is a long-jump to @code{sym2}. The original @samp{.word}
3781 contains @code{sym1} minus the address of the long-jump to
3784 If there were several occurrences of @samp{.word sym1-sym2} before the
3785 secondary jump table, all of them are adjusted. If there was a
3786 @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
3787 long-jump to @code{sym4} is included in the secondary jump table,
3788 and the @code{.word} directives are adjusted to contain @code{sym3}
3789 minus the address of the long-jump to @code{sym4}; and so on, for as many
3790 entries in the original jump table as necessary.
3793 @emph{This feature may be disabled by compiling @code{@value{AS}} with the
3794 @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
3795 assembly language programmers.
3798 @c end DIFF-TBL-KLUGE
3801 @section Deprecated Directives
3803 @cindex deprecated directives
3804 @cindex obsolescent directives
3805 One day these directives won't work.
3806 They are included for compatibility with older assemblers.
3814 @node Machine Dependencies
3815 @chapter Machine Dependent Features
3817 @cindex machine dependencies
3818 The machine instruction sets are (almost by definition) different on
3819 each machine where @code{@value{AS}} runs. Floating point representations
3820 vary as well, and @code{@value{AS}} often supports a few additional
3821 directives or command-line options for compatibility with other
3822 assemblers on a particular platform. Finally, some versions of
3823 @code{@value{AS}} support special pseudo-instructions for branch
3826 This chapter discusses most of these differences, though it does not
3827 include details on any machine's instruction set. For details on that
3828 subject, see the hardware manufacturer's manual.
3832 * Vax-Dependent:: VAX Dependent Features
3835 * AMD29K-Dependent:: AMD 29K Dependent Features
3838 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
3841 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
3844 * HPPA-Dependent:: HPPA Dependent Features
3847 * SH-Dependent:: Hitachi SH Dependent Features
3850 * i960-Dependent:: Intel 80960 Dependent Features
3853 * M68K-Dependent:: M680x0 Dependent Features
3856 * Sparc-Dependent:: SPARC Dependent Features
3859 * Z8000-Dependent:: Z8000 Dependent Features
3862 * MIPS-Dependent:: MIPS Dependent Features
3865 * i386-Dependent:: 80386 Dependent Features
3872 @c The following major nodes are *sections* in the GENERIC version, *chapters*
3873 @c in single-cpu versions. This is mainly achieved by @lowersections. There is a
3874 @c peculiarity: to preserve cross-references, there must be a node called
3875 @c "Machine Dependencies". Hence the conditional nodenames in each
3876 @c major node below. Node defaulting in makeinfo requires adjacency of
3877 @c node and sectioning commands; hence the repetition of @chapter BLAH
3878 @c in both conditional blocks.
3883 @chapter VAX Dependent Features
3888 @node Machine Dependencies
3889 @chapter VAX Dependent Features
3895 * Vax-Opts:: VAX Command-Line Options
3896 * VAX-float:: VAX Floating Point
3897 * VAX-directives:: Vax Machine Directives
3898 * VAX-opcodes:: VAX Opcodes
3899 * VAX-branch:: VAX Branch Improvement
3900 * VAX-operands:: VAX Operands
3901 * VAX-no:: Not Supported on VAX
3906 @section VAX Command-Line Options
3908 @cindex command-line options ignored, VAX
3909 @cindex VAX command-line options ignored
3910 The Vax version of @code{@value{AS}} accepts any of the following options,
3911 gives a warning message that the option was ignored and proceeds.
3912 These options are for compatibility with scripts designed for other
3913 people's assemblers.
3916 @item @code{-D} (Debug)
3917 @itemx @code{-S} (Symbol Table)
3918 @itemx @code{-T} (Token Trace)
3919 @cindex @code{-D}, ignored on VAX
3920 @cindex @code{-S}, ignored on VAX
3921 @cindex @code{-T}, ignored on VAX
3922 These are obsolete options used to debug old assemblers.
3924 @item @code{-d} (Displacement size for JUMPs)
3925 @cindex @code{-d}, VAX option
3926 This option expects a number following the @samp{-d}. Like options
3927 that expect filenames, the number may immediately follow the
3928 @samp{-d} (old standard) or constitute the whole of the command line
3929 argument that follows @samp{-d} (@sc{gnu} standard).
3931 @item @code{-V} (Virtualize Interpass Temporary File)
3932 @cindex @code{-V}, redundant on VAX
3933 Some other assemblers use a temporary file. This option
3934 commanded them to keep the information in active memory rather
3935 than in a disk file. @code{@value{AS}} always does this, so this
3936 option is redundant.
3938 @item @code{-J} (JUMPify Longer Branches)
3939 @cindex @code{-J}, ignored on VAX
3940 Many 32-bit computers permit a variety of branch instructions
3941 to do the same job. Some of these instructions are short (and
3942 fast) but have a limited range; others are long (and slow) but
3943 can branch anywhere in virtual memory. Often there are 3
3944 flavors of branch: short, medium and long. Some other
3945 assemblers would emit short and medium branches, unless told by
3946 this option to emit short and long branches.
3948 @item @code{-t} (Temporary File Directory)
3949 @cindex @code{-t}, ignored on VAX
3950 Some other assemblers may use a temporary file, and this option
3951 takes a filename being the directory to site the temporary
3952 file. Since @code{@value{AS}} does not use a temporary disk file, this
3953 option makes no difference. @samp{-t} needs exactly one
3957 @cindex VMS (VAX) options
3958 @cindex options for VAX/VMS
3959 @cindex VAX/VMS options
3960 @cindex @code{-h} option, VAX/VMS
3961 @cindex @code{-+} option, VAX/VMS
3962 @cindex Vax-11 C compatibility
3963 @cindex symbols with lowercase, VAX/VMS
3964 @c FIXME! look into "I think" below, correct if needed, delete.
3965 The Vax version of the assembler accepts two options when
3966 compiled for VMS. They are @samp{-h}, and @samp{-+}. The
3967 @samp{-h} option prevents @code{@value{AS}} from modifying the
3968 symbol-table entries for symbols that contain lowercase
3969 characters (I think). The @samp{-+} option causes @code{@value{AS}} to
3970 print warning messages if the FILENAME part of the object file,
3971 or any symbol name is larger than 31 characters. The @samp{-+}
3972 option also inserts some code following the @samp{_main}
3973 symbol so that the object file is compatible with Vax-11
3977 @section VAX Floating Point
3979 @cindex VAX floating point
3980 @cindex floating point, VAX
3981 Conversion of flonums to floating point is correct, and
3982 compatible with previous assemblers. Rounding is
3983 towards zero if the remainder is exactly half the least significant bit.
3985 @code{D}, @code{F}, @code{G} and @code{H} floating point formats
3988 Immediate floating literals (@emph{e.g.} @samp{S`$6.9})
3989 are rendered correctly. Again, rounding is towards zero in the
3992 @cindex @code{float} directive, VAX
3993 @cindex @code{double} directive, VAX
3994 The @code{.float} directive produces @code{f} format numbers.
3995 The @code{.double} directive produces @code{d} format numbers.
3997 @node VAX-directives
3998 @section Vax Machine Directives
4000 @cindex machine directives, VAX
4001 @cindex VAX machine directives
4002 The Vax version of the assembler supports four directives for
4003 generating Vax floating point constants. They are described in the
4006 @cindex wide floating point directives, VAX
4009 @cindex @code{dfloat} directive, VAX
4010 This expects zero or more flonums, separated by commas, and
4011 assembles Vax @code{d} format 64-bit floating point constants.
4014 @cindex @code{ffloat} directive, VAX
4015 This expects zero or more flonums, separated by commas, and
4016 assembles Vax @code{f} format 32-bit floating point constants.
4019 @cindex @code{gfloat} directive, VAX
4020 This expects zero or more flonums, separated by commas, and
4021 assembles Vax @code{g} format 64-bit floating point constants.
4024 @cindex @code{hfloat} directive, VAX
4025 This expects zero or more flonums, separated by commas, and
4026 assembles Vax @code{h} format 128-bit floating point constants.
4031 @section VAX Opcodes
4033 @cindex VAX opcode mnemonics
4034 @cindex opcode mnemonics, VAX
4035 @cindex mnemonics for opcodes, VAX
4036 All DEC mnemonics are supported. Beware that @code{case@dots{}}
4037 instructions have exactly 3 operands. The dispatch table that
4038 follows the @code{case@dots{}} instruction should be made with
4039 @code{.word} statements. This is compatible with all unix
4040 assemblers we know of.
4043 @section VAX Branch Improvement
4045 @cindex VAX branch improvement
4046 @cindex branch improvement, VAX
4047 @cindex pseudo-ops for branch, VAX
4048 Certain pseudo opcodes are permitted. They are for branch
4049 instructions. They expand to the shortest branch instruction that
4050 reaches the target. Generally these mnemonics are made by
4051 substituting @samp{j} for @samp{b} at the start of a DEC mnemonic.
4052 This feature is included both for compatibility and to help
4053 compilers. If you do not need this feature, avoid these
4054 opcodes. Here are the mnemonics, and the code they can expand into.
4058 @samp{Jsb} is already an instruction mnemonic, so we chose @samp{jbsb}.
4060 @item (byte displacement)
4062 @item (word displacement)
4064 @item (long displacement)
4069 Unconditional branch.
4071 @item (byte displacement)
4073 @item (word displacement)
4075 @item (long displacement)
4079 @var{COND} may be any one of the conditional branches
4080 @code{neq}, @code{nequ}, @code{eql}, @code{eqlu}, @code{gtr},
4081 @code{geq}, @code{lss}, @code{gtru}, @code{lequ}, @code{vc}, @code{vs},
4082 @code{gequ}, @code{cc}, @code{lssu}, @code{cs}.
4083 @var{COND} may also be one of the bit tests
4084 @code{bs}, @code{bc}, @code{bss}, @code{bcs}, @code{bsc}, @code{bcc},
4085 @code{bssi}, @code{bcci}, @code{lbs}, @code{lbc}.
4086 @var{NOTCOND} is the opposite condition to @var{COND}.
4088 @item (byte displacement)
4089 @kbd{b@var{COND} @dots{}}
4090 @item (word displacement)
4091 @kbd{b@var{NOTCOND} foo ; brw @dots{} ; foo:}
4092 @item (long displacement)
4093 @kbd{b@var{NOTCOND} foo ; jmp @dots{} ; foo:}
4096 @var{X} may be one of @code{b d f g h l w}.
4098 @item (word displacement)
4099 @kbd{@var{OPCODE} @dots{}}
4100 @item (long displacement)
4102 @var{OPCODE} @dots{}, foo ;
4109 @var{YYY} may be one of @code{lss leq}.
4111 @var{ZZZ} may be one of @code{geq gtr}.
4113 @item (byte displacement)
4114 @kbd{@var{OPCODE} @dots{}}
4115 @item (word displacement)
4117 @var{OPCODE} @dots{}, foo ;
4119 foo: brw @var{destination} ;
4122 @item (long displacement)
4124 @var{OPCODE} @dots{}, foo ;
4126 foo: jmp @var{destination} ;
4135 @item (byte displacement)
4136 @kbd{@var{OPCODE} @dots{}}
4137 @item (word displacement)
4139 @var{OPCODE} @dots{}, foo ;
4141 foo: brw @var{destination} ;
4144 @item (long displacement)
4146 @var{OPCODE} @dots{}, foo ;
4148 foo: jmp @var{destination} ;
4155 @section VAX Operands
4157 @cindex VAX operand notation
4158 @cindex operand notation, VAX
4159 @cindex immediate character, VAX
4160 @cindex VAX immediate character
4161 The immediate character is @samp{$} for Unix compatibility, not
4162 @samp{#} as DEC writes it.
4164 @cindex indirect character, VAX
4165 @cindex VAX indirect character
4166 The indirect character is @samp{*} for Unix compatibility, not
4167 @samp{@@} as DEC writes it.
4169 @cindex displacement sizing character, VAX
4170 @cindex VAX displacement sizing character
4171 The displacement sizing character is @samp{`} (an accent grave) for
4172 Unix compatibility, not @samp{^} as DEC writes it. The letter
4173 preceding @samp{`} may have either case. @samp{G} is not
4174 understood, but all other letters (@code{b i l s w}) are understood.
4176 @cindex register names, VAX
4177 @cindex VAX register names
4178 Register names understood are @code{r0 r1 r2 @dots{} r15 ap fp sp
4179 pc}. Upper and lower case letters are equivalent.
4186 Any expression is permitted in an operand. Operands are comma
4189 @c There is some bug to do with recognizing expressions
4190 @c in operands, but I forget what it is. It is
4191 @c a syntax clash because () is used as an address mode
4192 @c and to encapsulate sub-expressions.
4195 @section Not Supported on VAX
4197 @cindex VAX bitfields not supported
4198 @cindex bitfields, not supported on VAX
4199 Vax bit fields can not be assembled with @code{@value{AS}}. Someone
4200 can add the required code if they really need it.
4206 @node AMD29K-Dependent
4207 @chapter AMD 29K Dependent Features
4210 @node Machine Dependencies
4211 @chapter AMD 29K Dependent Features
4214 @cindex AMD 29K support
4217 * AMD29K Options:: Options
4218 * AMD29K Syntax:: Syntax
4219 * AMD29K Floating Point:: Floating Point
4220 * AMD29K Directives:: AMD 29K Machine Directives
4221 * AMD29K Opcodes:: Opcodes
4224 @node AMD29K Options
4226 @cindex AMD 29K options (none)
4227 @cindex options for AMD29K (none)
4228 @code{@value{AS}} has no additional command-line options for the AMD
4234 * AMD29K-Chars:: Special Characters
4235 * AMD29K-Regs:: Register Names
4239 @subsection Special Characters
4241 @cindex line comment character, AMD 29K
4242 @cindex AMD 29K line comment character
4243 @samp{;} is the line comment character.
4245 @cindex line separator, AMD 29K
4246 @cindex AMD 29K line separator
4247 @cindex statement separator, AMD 29K
4248 @cindex AMD 29K statement separator
4249 @samp{@@} can be used instead of a newline to separate statements.
4251 @cindex identifiers, AMD 29K
4252 @cindex AMD 29K identifiers
4253 The character @samp{?} is permitted in identifiers (but may not begin
4257 @subsection Register Names
4259 @cindex AMD 29K register names
4260 @cindex register names, AMD 29K
4261 General-purpose registers are represented by predefined symbols of the
4262 form @samp{GR@var{nnn}} (for global registers) or @samp{LR@var{nnn}}
4263 (for local registers), where @var{nnn} represents a number between
4264 @code{0} and @code{127}, written with no leading zeros. The leading
4265 letters may be in either upper or lower case; for example, @samp{gr13}
4266 and @samp{LR7} are both valid register names.
4268 You may also refer to general-purpose registers by specifying the
4269 register number as the result of an expression (prefixed with @samp{%%}
4270 to flag the expression as a register number):
4275 ---where @var{expression} must be an absolute expression evaluating to a
4276 number between @code{0} and @code{255}. The range [0, 127] refers to
4277 global registers, and the range [128, 255] to local registers.
4279 @cindex special purpose registers, AMD 29K
4280 @cindex AMD 29K special purpose registers
4281 @cindex protected registers, AMD 29K
4282 @cindex AMD 29K protected registers
4283 In addition, @code{@value{AS}} understands the following protected
4284 special-purpose register names for the AMD 29K family:
4294 These unprotected special-purpose register names are also recognized:
4302 @node AMD29K Floating Point
4303 @section Floating Point
4305 @cindex floating point, AMD 29K (@sc{ieee})
4306 @cindex AMD 29K floating point (@sc{ieee})
4307 The AMD 29K family uses @sc{ieee} floating-point numbers.
4309 @node AMD29K Directives
4310 @section AMD 29K Machine Directives
4312 @cindex machine directives, AMD 29K
4313 @cindex AMD 29K machine directives
4315 @item .block @var{size} , @var{fill}
4316 @cindex @code{block} directive, AMD 29K
4317 This directive emits @var{size} bytes, each of value @var{fill}. Both
4318 @var{size} and @var{fill} are absolute expressions. If the comma
4319 and @var{fill} are omitted, @var{fill} is assumed to be zero.
4321 In other versions of the @sc{gnu} assembler, this directive is called
4327 @cindex @code{cputype} directive, AMD 29K
4328 This directive is ignored; it is accepted for compatibility with other
4332 @cindex @code{file} directive, AMD 29K
4333 This directive is ignored; it is accepted for compatibility with other
4337 @emph{Warning:} in other versions of the @sc{gnu} assembler, @code{.file} is
4338 used for the directive called @code{.app-file} in the AMD 29K support.
4342 @cindex @code{line} directive, AMD 29K
4343 This directive is ignored; it is accepted for compatibility with other
4347 @c since we're ignoring .lsym...
4348 @item .reg @var{symbol}, @var{expression}
4349 @cindex @code{reg} directive, AMD 29K
4350 @code{.reg} has the same effect as @code{.lsym}; @pxref{Lsym,,@code{.lsym}}.
4354 @cindex @code{sect} directive, AMD 29K
4355 This directive is ignored; it is accepted for compatibility with other
4358 @item .use @var{section name}
4359 @cindex @code{use} directive, AMD 29K
4360 Establishes the section and subsection for the following code;
4361 @var{section name} may be one of @code{.text}, @code{.data},
4362 @code{.data1}, or @code{.lit}. With one of the first three @var{section
4363 name} options, @samp{.use} is equivalent to the machine directive
4364 @var{section name}; the remaining case, @samp{.use .lit}, is the same as
4368 @node AMD29K Opcodes
4371 @cindex AMD 29K opcodes
4372 @cindex opcodes for AMD 29K
4373 @code{@value{AS}} implements all the standard AMD 29K opcodes. No
4374 additional pseudo-instructions are needed on this family.
4376 For information on the 29K machine instruction set, see @cite{Am29000
4377 User's Manual}, Advanced Micro Devices, Inc.
4382 @node Machine Dependencies
4383 @chapter Machine Dependent Features
4385 The machine instruction sets are different on each Hitachi chip family,
4386 and there are also some syntax differences among the families. This
4387 chapter describes the specific @code{@value{AS}} features for each
4391 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
4392 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
4393 * SH-Dependent:: Hitachi SH Dependent Features
4403 @node H8/300-Dependent
4404 @chapter H8/300 Dependent Features
4406 @cindex H8/300 support
4408 * H8/300 Options:: Options
4409 * H8/300 Syntax:: Syntax
4410 * H8/300 Floating Point:: Floating Point
4411 * H8/300 Directives:: H8/300 Machine Directives
4412 * H8/300 Opcodes:: Opcodes
4415 @node H8/300 Options
4418 @cindex H8/300 options (none)
4419 @cindex options, H8/300 (none)
4420 @code{@value{AS}} has no additional command-line options for the Hitachi
4426 * H8/300-Chars:: Special Characters
4427 * H8/300-Regs:: Register Names
4428 * H8/300-Addressing:: Addressing Modes
4432 @subsection Special Characters
4434 @cindex line comment character, H8/300
4435 @cindex H8/300 line comment character
4436 @samp{;} is the line comment character.
4438 @cindex line separator, H8/300
4439 @cindex statement separator, H8/300
4440 @cindex H8/300 line separator
4441 @samp{$} can be used instead of a newline to separate statements.
4442 Therefore @emph{you may not use @samp{$} in symbol names} on the H8/300.
4445 @subsection Register Names
4447 @cindex H8/300 registers
4448 @cindex register names, H8/300
4449 You can use predefined symbols of the form @samp{r@var{n}h} and
4450 @samp{r@var{n}l} to refer to the H8/300 registers as sixteen 8-bit
4451 general-purpose registers. @var{n} is a digit from @samp{0} to
4452 @samp{7}); for instance, both @samp{r0h} and @samp{r7l} are valid
4455 You can also use the eight predefined symbols @samp{r@var{n}} to refer
4456 to the H8/300 registers as 16-bit registers (you must use this form for
4459 On the H8/300H, you can also use the eight predefined symbols
4460 @samp{er@var{n}} (@samp{er0} @dots{} @samp{er7}) to refer to the 32-bit
4461 general purpose registers.
4463 The two control registers are called @code{pc} (program counter; a
4464 16-bit register, except on the H8/300H where it is 24 bits) and
4465 @code{ccr} (condition code register; an 8-bit register). @code{r7} is
4466 used as the stack pointer, and can also be called @code{sp}.
4468 @node H8/300-Addressing
4469 @subsection Addressing Modes
4471 @cindex addressing modes, H8/300
4472 @cindex H8/300 addressing modes
4473 @value{AS} understands the following addressing modes for the H8/300:
4481 @item @@(@var{d}, r@var{n})
4482 @itemx @@(@var{d}:16, r@var{n})
4483 @itemx @@(@var{d}:24, r@var{n})
4484 Register indirect: 16-bit or 24-bit displacement @var{d} from register
4485 @var{n}. (24-bit displacements are only meaningful on the H8/300H.)
4488 Register indirect with post-increment
4491 Register indirect with pre-decrement
4493 @item @code{@@}@var{aa}
4494 @itemx @code{@@}@var{aa}:8
4495 @itemx @code{@@}@var{aa}:16
4496 @itemx @code{@@}@var{aa}:24
4497 Absolute address @code{aa}. (The address size @samp{:24} only makes
4498 sense on the H8/300H.)
4504 Immediate data @var{xx}. You may specify the @samp{:8}, @samp{:16}, or
4505 @samp{:32} for clarity, if you wish; but @code{@value{AS}} neither
4506 requires this nor uses it---the data size required is taken from
4509 @item @code{@@}@code{@@}@var{aa}
4510 @itemx @code{@@}@code{@@}@var{aa}:8
4511 Memory indirect. You may specify the @samp{:8} for clarity, if you
4512 wish; but @code{@value{AS}} neither requires this nor uses it.
4515 @node H8/300 Floating Point
4516 @section Floating Point
4518 @cindex floating point, H8/300 (@sc{ieee})
4519 @cindex H8/300 floating point (@sc{ieee})
4520 The H8/300 family has no hardware floating point, but the @code{.float}
4521 directive generates @sc{ieee} floating-point numbers for compatibility
4522 with other development tools.
4525 @node H8/300 Directives
4526 @section H8/300 Machine Directives
4528 @cindex H8/300 machine directives (none)
4529 @cindex machine directives, H8/300 (none)
4530 @cindex @code{word} directive, H8/300
4531 @cindex @code{int} directive, H8/300
4532 @code{@value{AS}} has only one machine-dependent directive for the
4536 @cindex H8/300H, assembling for
4538 Recognize and emit additional instructions for the H8/300H variant, and
4539 also make @code{.int} emit 32-bit numbers rather than the usual (16-bit)
4540 for the H8/300 family.
4543 On the H8/300 family (including the H8/300H) @samp{.word} directives
4544 generate 16-bit numbers.
4546 @node H8/300 Opcodes
4549 @cindex H8/300 opcode summary
4550 @cindex opcode summary, H8/300
4551 @cindex mnemonics, H8/300
4552 @cindex instruction summary, H8/300
4553 For detailed information on the H8/300 machine instruction set, see
4554 @cite{H8/300 Series Programming Manual} (Hitachi ADE--602--025). For
4555 information specific to the H8/300H, see @cite{H8/300H Series
4556 Programming Manual} (Hitachi).
4558 @code{@value{AS}} implements all the standard H8/300 opcodes. No additional
4559 pseudo-instructions are needed on this family.
4562 @c this table, due to the multi-col faking and hardcoded order, looks silly
4563 @c except in smallbook. See comments below "@set SMALL" near top of this file.
4565 The following table summarizes the H8/300 opcodes, and their arguments.
4566 Entries marked @samp{*} are opcodes used only on the H8/300H.
4569 @c Using @group seems to use the normal baselineskip, not the smallexample
4570 @c baselineskip; looks approx doublespaced.
4572 Rs @r{source register}
4573 Rd @r{destination register}
4574 abs @r{absolute address}
4575 imm @r{immediate data}
4576 disp:N @r{N-bit displacement from a register}
4577 pcrel:N @r{N-bit displacement relative to program counter}
4579 add.b #imm,rd * andc #imm,ccr
4580 add.b rs,rd band #imm,rd
4581 add.w rs,rd band #imm,@@rd
4582 * add.w #imm,rd band #imm,@@abs:8
4583 * add.l rs,rd bra pcrel:8
4584 * add.l #imm,rd * bra pcrel:16
4585 adds #imm,rd bt pcrel:8
4586 addx #imm,rd * bt pcrel:16
4587 addx rs,rd brn pcrel:8
4588 and.b #imm,rd * brn pcrel:16
4589 and.b rs,rd bf pcrel:8
4590 * and.w rs,rd * bf pcrel:16
4591 * and.w #imm,rd bhi pcrel:8
4592 * and.l #imm,rd * bhi pcrel:16
4593 * and.l rs,rd bls pcrel:8
4595 * bls pcrel:16 bld #imm,rd
4596 bcc pcrel:8 bld #imm,@@rd
4597 * bcc pcrel:16 bld #imm,@@abs:8
4598 bhs pcrel:8 bnot #imm,rd
4599 * bhs pcrel:16 bnot #imm,@@rd
4600 bcs pcrel:8 bnot #imm,@@abs:8
4601 * bcs pcrel:16 bnot rs,rd
4602 blo pcrel:8 bnot rs,@@rd
4603 * blo pcrel:16 bnot rs,@@abs:8
4604 bne pcrel:8 bor #imm,rd
4605 * bne pcrel:16 bor #imm,@@rd
4606 beq pcrel:8 bor #imm,@@abs:8
4607 * beq pcrel:16 bset #imm,rd
4608 bvc pcrel:8 bset #imm,@@rd
4609 * bvc pcrel:16 bset #imm,@@abs:8
4610 bvs pcrel:8 bset rs,rd
4611 * bvs pcrel:16 bset rs,@@rd
4612 bpl pcrel:8 bset rs,@@abs:8
4613 * bpl pcrel:16 bsr pcrel:8
4614 bmi pcrel:8 bsr pcrel:16
4615 * bmi pcrel:16 bst #imm,rd
4616 bge pcrel:8 bst #imm,@@rd
4617 * bge pcrel:16 bst #imm,@@abs:8
4618 blt pcrel:8 btst #imm,rd
4619 * blt pcrel:16 btst #imm,@@rd
4620 bgt pcrel:8 btst #imm,@@abs:8
4621 * bgt pcrel:16 btst rs,rd
4622 ble pcrel:8 btst rs,@@rd
4623 * ble pcrel:16 btst rs,@@abs:8
4624 bclr #imm,rd bxor #imm,rd
4625 bclr #imm,@@rd bxor #imm,@@rd
4626 bclr #imm,@@abs:8 bxor #imm,@@abs:8
4627 bclr rs,rd cmp.b #imm,rd
4628 bclr rs,@@rd cmp.b rs,rd
4629 bclr rs,@@abs:8 cmp.w rs,rd
4630 biand #imm,rd cmp.w rs,rd
4631 biand #imm,@@rd * cmp.w #imm,rd
4632 biand #imm,@@abs:8 * cmp.l #imm,rd
4633 bild #imm,rd * cmp.l rs,rd
4634 bild #imm,@@rd daa rs
4635 bild #imm,@@abs:8 das rs
4636 bior #imm,rd dec.b rs
4637 bior #imm,@@rd * dec.w #imm,rd
4638 bior #imm,@@abs:8 * dec.l #imm,rd
4639 bist #imm,rd divxu.b rs,rd
4640 bist #imm,@@rd * divxu.w rs,rd
4641 bist #imm,@@abs:8 * divxs.b rs,rd
4642 bixor #imm,rd * divxs.w rs,rd
4643 bixor #imm,@@rd eepmov
4644 bixor #imm,@@abs:8 * eepmovw
4646 * exts.w rd mov.w rs,@@abs:16
4647 * exts.l rd * mov.l #imm,rd
4648 * extu.w rd * mov.l rs,rd
4649 * extu.l rd * mov.l @@rs,rd
4650 inc rs * mov.l @@(disp:16,rs),rd
4651 * inc.w #imm,rd * mov.l @@(disp:24,rs),rd
4652 * inc.l #imm,rd * mov.l @@rs+,rd
4653 jmp @@rs * mov.l @@abs:16,rd
4654 jmp abs * mov.l @@abs:24,rd
4655 jmp @@@@abs:8 * mov.l rs,@@rd
4656 jsr @@rs * mov.l rs,@@(disp:16,rd)
4657 jsr abs * mov.l rs,@@(disp:24,rd)
4658 jsr @@@@abs:8 * mov.l rs,@@-rd
4659 ldc #imm,ccr * mov.l rs,@@abs:16
4660 ldc rs,ccr * mov.l rs,@@abs:24
4661 * ldc @@abs:16,ccr movfpe @@abs:16,rd
4662 * ldc @@abs:24,ccr movtpe rs,@@abs:16
4663 * ldc @@(disp:16,rs),ccr mulxu.b rs,rd
4664 * ldc @@(disp:24,rs),ccr * mulxu.w rs,rd
4665 * ldc @@rs+,ccr * mulxs.b rs,rd
4666 * ldc @@rs,ccr * mulxs.w rs,rd
4667 * mov.b @@(disp:24,rs),rd neg.b rs
4668 * mov.b rs,@@(disp:24,rd) * neg.w rs
4669 mov.b @@abs:16,rd * neg.l rs
4671 mov.b @@abs:8,rd not.b rs
4672 mov.b rs,@@abs:8 * not.w rs
4673 mov.b rs,rd * not.l rs
4674 mov.b #imm,rd or.b #imm,rd
4675 mov.b @@rs,rd or.b rs,rd
4676 mov.b @@(disp:16,rs),rd * or.w #imm,rd
4677 mov.b @@rs+,rd * or.w rs,rd
4678 mov.b @@abs:8,rd * or.l #imm,rd
4679 mov.b rs,@@rd * or.l rs,rd
4680 mov.b rs,@@(disp:16,rd) orc #imm,ccr
4681 mov.b rs,@@-rd pop.w rs
4682 mov.b rs,@@abs:8 * pop.l rs
4683 mov.w rs,@@rd push.w rs
4684 * mov.w @@(disp:24,rs),rd * push.l rs
4685 * mov.w rs,@@(disp:24,rd) rotl.b rs
4686 * mov.w @@abs:24,rd * rotl.w rs
4687 * mov.w rs,@@abs:24 * rotl.l rs
4688 mov.w rs,rd rotr.b rs
4689 mov.w #imm,rd * rotr.w rs
4690 mov.w @@rs,rd * rotr.l rs
4691 mov.w @@(disp:16,rs),rd rotxl.b rs
4692 mov.w @@rs+,rd * rotxl.w rs
4693 mov.w @@abs:16,rd * rotxl.l rs
4694 mov.w rs,@@(disp:16,rd) rotxr.b rs
4695 mov.w rs,@@-rd * rotxr.w rs
4697 * rotxr.l rs * stc ccr,@@(disp:24,rd)
4699 rte * stc ccr,@@abs:16
4700 rts * stc ccr,@@abs:24
4701 shal.b rs sub.b rs,rd
4702 * shal.w rs sub.w rs,rd
4703 * shal.l rs * sub.w #imm,rd
4704 shar.b rs * sub.l rs,rd
4705 * shar.w rs * sub.l #imm,rd
4706 * shar.l rs subs #imm,rd
4707 shll.b rs subx #imm,rd
4708 * shll.w rs subx rs,rd
4709 * shll.l rs * trapa #imm
4710 shlr.b rs xor #imm,rd
4711 * shlr.w rs xor rs,rd
4712 * shlr.l rs * xor.w #imm,rd
4714 stc ccr,rd * xor.l #imm,rd
4715 * stc ccr,@@rs * xor.l rs,rd
4716 * stc ccr,@@(disp:16,rd) xorc #imm,ccr
4720 @cindex size suffixes, H8/300
4721 @cindex H8/300 size suffixes
4722 Four H8/300 instructions (@code{add}, @code{cmp}, @code{mov},
4723 @code{sub}) are defined with variants using the suffixes @samp{.b},
4724 @samp{.w}, and @samp{.l} to specify the size of a memory operand.
4725 @code{@value{AS}} supports these suffixes, but does not require them;
4726 since one of the operands is always a register, @code{@value{AS}} can
4727 deduce the correct size.
4729 For example, since @code{r0} refers to a 16-bit register,
4732 @exdent is equivalent to
4736 If you use the size suffixes, @code{@value{AS}} issues a warning when
4737 the suffix and the register size do not match.
4742 @node H8/500-Dependent
4743 @chapter H8/500 Dependent Features
4745 @cindex H8/500 support
4747 * H8/500 Options:: Options
4748 * H8/500 Syntax:: Syntax
4749 * H8/500 Floating Point:: Floating Point
4750 * H8/500 Directives:: H8/500 Machine Directives
4751 * H8/500 Opcodes:: Opcodes
4754 @node H8/500 Options
4757 @cindex H8/500 options (none)
4758 @cindex options, H8/500 (none)
4759 @code{@value{AS}} has no additional command-line options for the Hitachi
4766 * H8/500-Chars:: Special Characters
4767 * H8/500-Regs:: Register Names
4768 * H8/500-Addressing:: Addressing Modes
4772 @subsection Special Characters
4774 @cindex line comment character, H8/500
4775 @cindex H8/500 line comment character
4776 @samp{!} is the line comment character.
4778 @cindex line separator, H8/500
4779 @cindex statement separator, H8/500
4780 @cindex H8/500 line separator
4781 @samp{;} can be used instead of a newline to separate statements.
4783 @cindex symbol names, @samp{$} in
4784 @cindex @code{$} in symbol names
4785 Since @samp{$} has no special meaning, you may use it in symbol names.
4788 @subsection Register Names
4790 @cindex H8/500 registers
4791 @cindex registers, H8/500
4792 You can use the predefined symbols @samp{r0}, @samp{r1}, @samp{r2},
4793 @samp{r3}, @samp{r4}, @samp{r5}, @samp{r6}, and @samp{r7} to refer to
4794 the H8/500 registers.
4796 The H8/500 also has these control registers:
4818 condition code register
4821 All registers are 16 bits long. To represent 32 bit numbers, use two
4822 adjacent registers; for distant memory addresses, use one of the segment
4823 pointers (@code{cp} for the program counter; @code{dp} for
4824 @code{r0}--@code{r3}; @code{ep} for @code{r4} and @code{r5}; and
4825 @code{tp} for @code{r6} and @code{r7}.
4827 @node H8/500-Addressing
4828 @subsection Addressing Modes
4830 @cindex addressing modes, H8/500
4831 @cindex H8/500 addressing modes
4832 @value{AS} understands the following addressing modes for the H8/500:
4840 @item @@(d:8, R@var{n})
4841 Register indirect with 8 bit signed displacement
4843 @item @@(d:16, R@var{n})
4844 Register indirect with 16 bit signed displacement
4847 Register indirect with pre-decrement
4850 Register indirect with post-increment
4853 8 bit absolute address
4856 16 bit absolute address
4865 @node H8/500 Floating Point
4866 @section Floating Point
4868 @cindex floating point, H8/500 (@sc{ieee})
4869 @cindex H8/500 floating point (@sc{ieee})
4870 The H8/500 family uses @sc{ieee} floating-point numbers.
4872 @node H8/500 Directives
4873 @section H8/500 Machine Directives
4875 @cindex H8/500 machine directives (none)
4876 @cindex machine directives, H8/500 (none)
4877 @cindex @code{word} directive, H8/500
4878 @cindex @code{int} directive, H8/500
4879 @code{@value{AS}} has no machine-dependent directives for the H8/500.
4880 However, on this platform the @samp{.int} and @samp{.word} directives
4881 generate 16-bit numbers.
4883 @node H8/500 Opcodes
4886 @cindex H8/500 opcode summary
4887 @cindex opcode summary, H8/500
4888 @cindex mnemonics, H8/500
4889 @cindex instruction summary, H8/500
4890 For detailed information on the H8/500 machine instruction set, see
4891 @cite{H8/500 Series Programming Manual} (Hitachi M21T001).
4893 @code{@value{AS}} implements all the standard H8/500 opcodes. No additional
4894 pseudo-instructions are needed on this family.
4897 @c this table, due to the multi-col faking and hardcoded order, looks silly
4898 @c except in smallbook. See comments below "@set SMALL" near top of this file.
4900 The following table summarizes H8/500 opcodes and their operands:
4902 @c Use @group if it ever works, instead of @page
4906 abs8 @r{8-bit absolute address}
4907 abs16 @r{16-bit absolute address}
4908 abs24 @r{24-bit absolute address}
4909 crb @r{@code{ccr}, @code{br}, @code{ep}, @code{dp}, @code{tp}, @code{dp}}
4910 disp8 @r{8-bit displacement}
4911 ea @r{@code{rn}, @code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
4912 @r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16},}
4913 @r{@code{#xx:8}, @code{#xx:16}}
4914 ea_mem @r{@code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
4915 @r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16}}
4916 ea_noimm @r{@code{rn}, @code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
4917 @r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16}}
4919 imm4 @r{4-bit immediate data}
4920 imm8 @r{8-bit immediate data}
4921 imm16 @r{16-bit immediate data}
4922 pcrel8 @r{8-bit offset from program counter}
4923 pcrel16 @r{16-bit offset from program counter}
4924 qim @r{@code{-2}, @code{-1}, @code{1}, @code{2}}
4926 rs @r{a register distinct from rd}
4927 rlist @r{comma-separated list of registers in parentheses;}
4928 @r{register ranges @code{rd-rs} are allowed}
4929 sp @r{stack pointer (@code{r7})}
4930 sr @r{status register}
4931 sz @r{size; @samp{.b} or @samp{.w}. If omitted, default @samp{.w}}
4933 ldc[.b] ea,crb bcc[.w] pcrel16
4934 ldc[.w] ea,sr bcc[.b] pcrel8
4935 add[:q] sz qim,ea_noimm bhs[.w] pcrel16
4936 add[:g] sz ea,rd bhs[.b] pcrel8
4937 adds sz ea,rd bcs[.w] pcrel16
4938 addx sz ea,rd bcs[.b] pcrel8
4939 and sz ea,rd blo[.w] pcrel16
4940 andc[.b] imm8,crb blo[.b] pcrel8
4941 andc[.w] imm16,sr bne[.w] pcrel16
4943 bra[.w] pcrel16 beq[.w] pcrel16
4944 bra[.b] pcrel8 beq[.b] pcrel8
4945 bt[.w] pcrel16 bvc[.w] pcrel16
4946 bt[.b] pcrel8 bvc[.b] pcrel8
4947 brn[.w] pcrel16 bvs[.w] pcrel16
4948 brn[.b] pcrel8 bvs[.b] pcrel8
4949 bf[.w] pcrel16 bpl[.w] pcrel16
4950 bf[.b] pcrel8 bpl[.b] pcrel8
4951 bhi[.w] pcrel16 bmi[.w] pcrel16
4952 bhi[.b] pcrel8 bmi[.b] pcrel8
4953 bls[.w] pcrel16 bge[.w] pcrel16
4954 bls[.b] pcrel8 bge[.b] pcrel8
4956 blt[.w] pcrel16 mov[:g][.b] imm8,ea_mem
4957 blt[.b] pcrel8 mov[:g][.w] imm16,ea_mem
4958 bgt[.w] pcrel16 movfpe[.b] ea,rd
4959 bgt[.b] pcrel8 movtpe[.b] rs,ea_noimm
4960 ble[.w] pcrel16 mulxu sz ea,rd
4961 ble[.b] pcrel8 neg sz ea
4962 bclr sz imm4,ea_noimm nop
4963 bclr sz rs,ea_noimm not sz ea
4964 bnot sz imm4,ea_noimm or sz ea,rd
4965 bnot sz rs,ea_noimm orc[.b] imm8,crb
4966 bset sz imm4,ea_noimm orc[.w] imm16,sr
4967 bset sz rs,ea_noimm pjmp abs24
4968 bsr[.b] pcrel8 pjmp @@rd
4969 bsr[.w] pcrel16 pjsr abs24
4970 btst sz imm4,ea_noimm pjsr @@rd
4971 btst sz rs,ea_noimm prtd imm8
4972 clr sz ea prtd imm16
4973 cmp[:e][.b] imm8,rd prts
4974 cmp[:i][.w] imm16,rd rotl sz ea
4975 cmp[:g].b imm8,ea_noimm rotr sz ea
4976 cmp[:g][.w] imm16,ea_noimm rotxl sz ea
4977 Cmp[:g] sz ea,rd rotxr sz ea
4979 divxu sz ea,rd rtd imm16
4981 exts[.b] rd scb/f rs,pcrel8
4982 extu[.b] rd scb/ne rs,pcrel8
4983 jmp @@rd scb/eq rs,pcrel8
4984 jmp @@(imm8,rd) shal sz ea
4985 jmp @@(imm16,rd) shar sz ea
4986 jmp abs16 shll sz ea
4988 jsr @@(imm8,rd) sleep
4989 jsr @@(imm16,rd) stc[.b] crb,ea_noimm
4990 jsr abs16 stc[.w] sr,ea_noimm
4991 ldm @@sp+,(rlist) stm (rlist),@@-sp
4992 link fp,imm8 sub sz ea,rd
4993 link fp,imm16 subs sz ea,rd
4994 mov[:e][.b] imm8,rd subx sz ea,rd
4995 mov[:i][.w] imm16,rd swap[.b] rd
4996 mov[:l][.w] abs8,rd tas[.b] ea
4997 mov[:l].b abs8,rd trapa imm4
4998 mov[:s][.w] rs,abs8 trap/vs
4999 mov[:s].b rs,abs8 tst sz ea
5000 mov[:f][.w] @@(disp8,fp),rd unlk fp
5001 mov[:f][.w] rs,@@(disp8,fp) xch[.w] rs,rd
5002 mov[:f].b @@(disp8,fp),rd xor sz ea,rd
5003 mov[:f].b rs,@@(disp8,fp) xorc.b imm8,crb
5004 mov[:g] sz rs,ea_mem xorc.w imm16,sr
5012 @node HPPA-Dependent
5013 @chapter HPPA Dependent Features
5017 * HPPA Notes:: Notes
5018 * HPPA Options:: Options
5019 * HPPA Syntax:: Syntax
5020 * HPPA Floating Point:: Floating Point
5021 * HPPA Directives:: HPPA Machine Directives
5022 * HPPA Opcodes:: Opcodes
5027 As a back end for @sc{gnu} @sc{cc} @code{@value{AS}} has been throughly tested and should
5028 work extremely well. We have tested it only minimally on hand written assembly
5029 code and no one has tested it much on the assembly output from the HP
5032 The format of the debugging sections has changed since the original
5033 @code{@value{AS}} port (version 1.3X) was released; therefore,
5034 you must rebuild all HPPA objects and libraries with the new
5035 assembler so that you can debug the final executable.
5037 The HPPA @code{@value{AS}} port generates a small subset of the relocations
5038 available in the SOM and ELF object file formats. Additional relocation
5039 support will be added as it becomes necessary.
5043 @code{@value{AS}} has no machine-dependent command-line options for the HPPA.
5048 The assembler syntax closely follows the HPPA instruction set
5049 reference manual; assembler directives and general syntax closely follow the
5050 HPPA assembly language reference manual, with a few noteworthy differences.
5052 First, a colon may immediately follow a label definition. This is
5053 simply for compatibility with how most assembly language programmers
5056 Some obscure expression parsing problems may affect hand written code which
5057 uses the @code{spop} instructions, or code which makes significant
5058 use of the @code{!} line separator.
5060 @code{@value{AS}} is much less forgiving about missing arguments and other
5061 similar oversights than the HP assembler. @code{@value{AS}} notifies you
5062 of missing arguments as syntax errors; this is regarded as a feature, not a
5065 Finally, @code{@value{AS}} allows you to use an external symbol without
5066 explicitly importing the symbol. @emph{Warning:} in the future this will be
5067 an error for HPPA targets.
5069 Special characters for HPPA targets include:
5071 @samp{;} is the line comment character.
5073 @samp{!} can be used instead of a newline to separate statements.
5075 Since @samp{$} has no special meaning, you may use it in symbol names.
5077 @node HPPA Floating Point
5078 @section Floating Point
5079 @cindex floating point, HPPA (@sc{ieee})
5080 @cindex HPPA floating point (@sc{ieee})
5081 The HPPA family uses @sc{ieee} floating-point numbers.
5083 @node HPPA Directives
5084 @section HPPA Assembler Directives
5086 @code{@value{AS}} for the HPPA supports many additional directives for
5087 compatibility with the native assembler. This section describes them only
5088 briefly. For detailed information on HPPA-specific assembler directives, see
5089 @cite{HP9000 Series 800 Assembly Language Reference Manual} (HP 92432-90001).
5091 @cindex HPPA directives not supported
5092 @code{@value{AS}} does @emph{not} support the following assembler directives
5093 described in the HP manual:
5102 @cindex @code{.param} on HPPA
5103 Beyond those implemented for compatibility, @code{@value{AS}} supports one
5104 additional assembler directive for the HPPA: @code{.param}. It conveys
5105 register argument locations for static functions. Its syntax closely follows
5106 the @code{.export} directive.
5108 @cindex HPPA-only directives
5109 These are the additional directives in @code{@value{AS}} for the HPPA:
5112 @item .block @var{n}
5113 @itemx .blockz @var{n}
5114 Reserve @var{n} bytes of storage, and initialize them to zero.
5117 Mark the beginning of a procedure call. Only the special case with @emph{no
5118 arguments} is allowed.
5120 @item .callinfo [ @var{param}=@var{value}, @dots{} ] [ @var{flag}, @dots{} ]
5121 Specify a number of parameters and flags that define the environment for a
5124 @var{param} may be any of @samp{frame} (frame size), @samp{entry_gr} (end of
5125 general register range), @samp{entry_fr} (end of float register range),
5126 @samp{entry_sr} (end of space register range).
5128 The values for @var{flag} are @samp{calls} or @samp{caller} (proc has
5129 subroutines), @samp{no_calls} (proc does not call subroutines), @samp{save_rp}
5130 (preserve return pointer), @samp{save_sp} (proc preserves stack pointer),
5131 @samp{no_unwind} (do not unwind this proc), @samp{hpux_int} (proc is interrupt
5135 Assemble into the standard section called @samp{$TEXT$}, subsection
5139 @item .copyright "@var{string}"
5140 In the SOM object format, insert @var{string} into the object code, marked as a
5145 @item .copyright "@var{string}"
5146 In the ELF object format, insert @var{string} into the object code, marked as a
5151 Not yet supported; the assembler rejects programs containing this directive.
5154 Mark the beginning of a procedure.
5157 Mark the end of a procedure.
5159 @item .export @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
5160 Make a procedure @var{name} available to callers. @var{typ}, if present, must
5161 be one of @samp{absolute}, @samp{code} (ELF only, not SOM), @samp{data},
5162 @samp{entry}, @samp{data}, @samp{entry}, @samp{millicode}, @samp{plabel},
5163 @samp{pri_prog}, or @samp{sec_prog}.
5165 @var{param}, if present, provides either relocation information for the
5166 procedure arguments and result, or a privilege level. @var{param} may be
5167 @samp{argw@var{n}} (where @var{n} ranges from @code{0} to @code{3}, and
5168 indicates one of four one-word arguments); @samp{rtnval} (the procedure's
5169 result); or @samp{priv_lev} (privilege level). For arguments or the result,
5170 @var{r} specifies how to relocate, and must be one of @samp{no} (not
5171 relocatable), @samp{gr} (argument is in general register), @samp{fr} (in
5172 floating point register), or @samp{fu} (upper half of float register).
5173 For @samp{priv_lev}, @var{r} is an integer.
5176 Define a two-byte integer constant @var{n}; synonym for the portable
5177 @code{@value{AS}} directive @code{.short}.
5179 @item .import @var{name} [ ,@var{typ} ]
5180 Converse of @code{.export}; make a procedure available to call. The arguments
5181 use the same conventions as the first two arguments for @code{.export}.
5183 @item .label @var{name}
5184 Define @var{name} as a label for the current assembly location.
5187 Not yet supported; the assembler rejects programs containing this directive.
5189 @item .origin @var{lc}
5190 Advance location counter to @var{lc}. Synonym for the @code{@value{as}}
5191 portable directive @code{.org}.
5193 @item .param @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
5194 @c Not in HP manual; GNU HPPA extension
5195 Similar to @code{.export}, but used for static procedures.
5198 Use preceding the first statement of a procedure.
5201 Use following the last statement of a procedure.
5203 @item @var{label} .reg @var{expr}
5204 @c ?? Not in HP manual (Jan 1988 vn)
5205 Synonym for @code{.equ}; define @var{label} with the absolute expression
5206 @var{expr} as its value.
5208 @item .space @var{secname} [ ,@var{params} ]
5209 Switch to section @var{secname}, creating a new section by that name if
5210 necessary. You may only use @var{params} when creating a new section, not
5211 when switching to an existing one. @var{secname} may identify a section by
5212 number rather than by name.
5214 If specified, the list @var{params} declares attributes of the section,
5215 identified by keywords. The keywords recognized are @samp{spnum=@var{exp}}
5216 (identify this section by the number @var{exp}, an absolute expression),
5217 @samp{sort=@var{exp}} (order sections according to this sort key when linking;
5218 @var{exp} is an absolute expression), @samp{unloadable} (section contains no
5219 loadable data), @samp{notdefined} (this section defined elsewhere), and
5220 @samp{private} (data in this section not available to other programs).
5222 @item .spnum @var{secnam}
5223 @c ?? Not in HP manual (Jan 1988)
5224 Allocate four bytes of storage, and initialize them with the section number of
5225 the section named @var{secnam}. (You can define the section number with the
5226 HPPA @code{.space} directive.)
5228 @item .string "@var{str}"
5229 @cindex @code{string} directive on HPPA
5230 Copy the characters in the string @var{str} to the object file.
5231 @xref{Strings,,Strings}, for information on escape sequences you can use in
5232 @code{@value{AS}} strings.
5234 @emph{Warning!} The HPPA version of @code{.string} differs from the
5235 usual @code{@value{AS}} definition: it does @emph{not} write a zero byte
5236 after copying @var{str}.
5238 @item .stringz "@var{str}"
5239 Like @code{.string}, but appends a zero byte after copying @var{str} to object
5242 @item .subspa @var{name} [ ,@var{params} ]
5243 Similar to @code{.space}, but selects a subsection @var{name} within the
5244 current section. You may only specify @var{params} when you create a
5245 subsection (in the first instance of @code{.subspa} for this @var{name}).
5247 If specified, the list @var{params} declares attributes of the subsection,
5248 identified by keywords. The keywords recognized are @samp{quad=@var{expr}}
5249 (``quadrant'' for this subsection), @samp{align=@var{expr}} (alignment for
5250 beginning of this subsection; a power of two), @samp{access=@var{expr}} (value
5251 for ``access rights'' field), @samp{sort=@var{expr}} (sorting order for this
5252 subspace in link), @samp{code_only} (subsection contains only code),
5253 @samp{unloadable} (subsection cannot be loaded into memory), @samp{common}
5254 (subsection is common block), @samp{dup_comm} (initialized data may have
5255 duplicate names), or @samp{zero} (subsection is all zeros, do not write in
5258 @item .version "@var{str}"
5259 Write @var{str} as version identifier in object code.
5264 For detailed information on the HPPA machine instruction set, see
5265 @cite{PA-RISC Architecture and Instruction Set Reference Manual}
5272 @chapter Hitachi SH Dependent Features
5276 * SH Options:: Options
5277 * SH Syntax:: Syntax
5278 * SH Floating Point:: Floating Point
5279 * SH Directives:: SH Machine Directives
5280 * SH Opcodes:: Opcodes
5286 @cindex SH options (none)
5287 @cindex options, SH (none)
5288 @code{@value{AS}} has no additional command-line options for the Hitachi
5295 * SH-Chars:: Special Characters
5296 * SH-Regs:: Register Names
5297 * SH-Addressing:: Addressing Modes
5301 @subsection Special Characters
5303 @cindex line comment character, SH
5304 @cindex SH line comment character
5305 @samp{!} is the line comment character.
5307 @cindex line separator, SH
5308 @cindex statement separator, SH
5309 @cindex SH line separator
5310 You can use @samp{;} instead of a newline to separate statements.
5312 @cindex symbol names, @samp{$} in
5313 @cindex @code{$} in symbol names
5314 Since @samp{$} has no special meaning, you may use it in symbol names.
5317 @subsection Register Names
5319 @cindex SH registers
5320 @cindex registers, SH
5321 You can use the predefined symbols @samp{r0}, @samp{r1}, @samp{r2},
5322 @samp{r3}, @samp{r4}, @samp{r5}, @samp{r6}, @samp{r7}, @samp{r8},
5323 @samp{r9}, @samp{r10}, @samp{r11}, @samp{r12}, @samp{r13}, @samp{r14},
5324 and @samp{r15} to refer to the SH registers.
5326 The SH also has these control registers:
5330 procedure register (holds return address)
5337 high and low multiply accumulator registers
5343 global base register
5346 vector base register (for interrupt vectors)
5350 @subsection Addressing Modes
5352 @cindex addressing modes, SH
5353 @cindex SH addressing modes
5354 @code{@value{AS}} understands the following addressing modes for the SH.
5355 @code{R@var{n}} in the following refers to any of the numbered
5356 registers, but @emph{not} the control registers.
5366 Register indirect with pre-decrement
5369 Register indirect with post-increment
5371 @item @@(@var{disp}, R@var{n})
5372 Register indirect with displacement
5374 @item @@(R0, R@var{n})
5377 @item @@(@var{disp}, GBR)
5384 @itemx @@(@var{disp}, PC)
5385 PC relative address (for branch or for addressing memory). The
5386 @code{@value{AS}} implementation allows you to use the simpler form
5387 @var{addr} anywhere a PC relative address is called for; the alternate
5388 form is supported for compatibility with other assemblers.
5394 @node SH Floating Point
5395 @section Floating Point
5397 @cindex floating point, SH (@sc{ieee})
5398 @cindex SH floating point (@sc{ieee})
5399 The SH family uses @sc{ieee} floating-point numbers.
5402 @section SH Machine Directives
5404 @cindex SH machine directives (none)
5405 @cindex machine directives, SH (none)
5406 @cindex @code{word} directive, SH
5407 @cindex @code{int} directive, SH
5408 @code{@value{AS}} has no machine-dependent directives for the SH.
5413 @cindex SH opcode summary
5414 @cindex opcode summary, SH
5415 @cindex mnemonics, SH
5416 @cindex instruction summary, SH
5417 For detailed information on the SH machine instruction set, see
5418 @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
5420 @code{@value{AS}} implements all the standard SH opcodes. No additional
5421 pseudo-instructions are needed on this family. Note, however, that
5422 because @code{@value{AS}} supports a simpler form of PC-relative
5423 addressing, you may simply write (for example)
5430 where other assemblers might require an explicit displacement to
5431 @code{bar} from the program counter:
5434 mov.l @@(@var{disp}, PC)
5438 @c this table, due to the multi-col faking and hardcoded order, looks silly
5439 @c except in smallbook. See comments below "@set SMALL" near top of this file.
5441 Here is a summary of SH opcodes:
5446 Rn @r{a numbered register}
5447 Rm @r{another numbered register}
5448 #imm @r{immediate data}
5449 disp @r{displacement}
5450 disp8 @r{8-bit displacement}
5451 disp12 @r{12-bit displacement}
5453 add #imm,Rn lds.l @@Rn+,PR
5454 add Rm,Rn mac.w @@Rm+,@@Rn+
5455 addc Rm,Rn mov #imm,Rn
5456 addv Rm,Rn mov Rm,Rn
5457 and #imm,R0 mov.b Rm,@@(R0,Rn)
5458 and Rm,Rn mov.b Rm,@@-Rn
5459 and.b #imm,@@(R0,GBR) mov.b Rm,@@Rn
5460 bf disp8 mov.b @@(disp,Rm),R0
5461 bra disp12 mov.b @@(disp,GBR),R0
5462 bsr disp12 mov.b @@(R0,Rm),Rn
5463 bt disp8 mov.b @@Rm+,Rn
5464 clrmac mov.b @@Rm,Rn
5465 clrt mov.b R0,@@(disp,Rm)
5466 cmp/eq #imm,R0 mov.b R0,@@(disp,GBR)
5467 cmp/eq Rm,Rn mov.l Rm,@@(disp,Rn)
5468 cmp/ge Rm,Rn mov.l Rm,@@(R0,Rn)
5469 cmp/gt Rm,Rn mov.l Rm,@@-Rn
5470 cmp/hi Rm,Rn mov.l Rm,@@Rn
5471 cmp/hs Rm,Rn mov.l @@(disp,Rn),Rm
5472 cmp/pl Rn mov.l @@(disp,GBR),R0
5473 cmp/pz Rn mov.l @@(disp,PC),Rn
5474 cmp/str Rm,Rn mov.l @@(R0,Rm),Rn
5475 div0s Rm,Rn mov.l @@Rm+,Rn
5477 div1 Rm,Rn mov.l R0,@@(disp,GBR)
5478 exts.b Rm,Rn mov.w Rm,@@(R0,Rn)
5479 exts.w Rm,Rn mov.w Rm,@@-Rn
5480 extu.b Rm,Rn mov.w Rm,@@Rn
5481 extu.w Rm,Rn mov.w @@(disp,Rm),R0
5482 jmp @@Rn mov.w @@(disp,GBR),R0
5483 jsr @@Rn mov.w @@(disp,PC),Rn
5484 ldc Rn,GBR mov.w @@(R0,Rm),Rn
5485 ldc Rn,SR mov.w @@Rm+,Rn
5486 ldc Rn,VBR mov.w @@Rm,Rn
5487 ldc.l @@Rn+,GBR mov.w R0,@@(disp,Rm)
5488 ldc.l @@Rn+,SR mov.w R0,@@(disp,GBR)
5489 ldc.l @@Rn+,VBR mova @@(disp,PC),R0
5491 lds Rn,MACL muls Rm,Rn
5492 lds Rn,PR mulu Rm,Rn
5493 lds.l @@Rn+,MACH neg Rm,Rn
5494 lds.l @@Rn+,MACL negc Rm,Rn
5497 not Rm,Rn stc.l GBR,@@-Rn
5498 or #imm,R0 stc.l SR,@@-Rn
5499 or Rm,Rn stc.l VBR,@@-Rn
5500 or.b #imm,@@(R0,GBR) sts MACH,Rn
5501 rotcl Rn sts MACL,Rn
5503 rotl Rn sts.l MACH,@@-Rn
5504 rotr Rn sts.l MACL,@@-Rn
5509 shar Rn swap.b Rm,Rn
5510 shll Rn swap.w Rm,Rn
5511 shll16 Rn tas.b @@Rn
5513 shll8 Rn tst #imm,R0
5515 shlr16 Rn tst.b #imm,@@(R0,GBR)
5516 shlr2 Rn xor #imm,R0
5518 sleep xor.b #imm,@@(R0,GBR)
5519 stc GBR,Rn xtrct Rm,Rn
5534 @node i960-Dependent
5535 @chapter Intel 80960 Dependent Features
5538 @node Machine Dependencies
5539 @chapter Intel 80960 Dependent Features
5542 @cindex i960 support
5544 * Options-i960:: i960 Command-line Options
5545 * Floating Point-i960:: Floating Point
5546 * Directives-i960:: i960 Machine Directives
5547 * Opcodes for i960:: i960 Opcodes
5550 @c FIXME! Add Syntax sec with discussion of bitfields here, at least so
5551 @c long as they're not turned on for other machines than 960.
5555 @section i960 Command-line Options
5557 @cindex i960 options
5558 @cindex options, i960
5561 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
5562 @cindex i960 architecture options
5563 @cindex architecture options, i960
5564 @cindex @code{-A} options, i960
5565 Select the 80960 architecture. Instructions or features not supported
5566 by the selected architecture cause fatal errors.
5568 @samp{-ACA} is equivalent to @samp{-ACA_A}; @samp{-AKC} is equivalent to
5569 @samp{-AMC}. Synonyms are provided for compatibility with other tools.
5571 If you do not specify any of these options, @code{@value{AS}} generates code
5572 for any instruction or feature that is supported by @emph{some} version of the
5573 960 (even if this means mixing architectures!). In principle,
5574 @code{@value{AS}} attempts to deduce the minimal sufficient processor type if
5575 none is specified; depending on the object code format, the processor type may
5576 be recorded in the object file. If it is critical that the @code{@value{AS}}
5577 output match a specific architecture, specify that architecture explicitly.
5580 @cindex @code{-b} option, i960
5581 @cindex branch recording, i960
5582 @cindex i960 branch recording
5583 Add code to collect information about conditional branches taken, for
5584 later optimization using branch prediction bits. (The conditional branch
5585 instructions have branch prediction bits in the CA, CB, and CC
5586 architectures.) If @var{BR} represents a conditional branch instruction,
5587 the following represents the code generated by the assembler when
5588 @samp{-b} is specified:
5591 call @var{increment routine}
5592 .word 0 # pre-counter
5594 call @var{increment routine}
5595 .word 0 # post-counter
5598 The counter following a branch records the number of times that branch
5599 was @emph{not} taken; the differenc between the two counters is the
5600 number of times the branch @emph{was} taken.
5602 @cindex @code{gbr960}, i960 postprocessor
5603 @cindex branch statistics table, i960
5604 A table of every such @code{Label} is also generated, so that the
5605 external postprocessor @code{gbr960} (supplied by Intel) can locate all
5606 the counters. This table is always labelled @samp{__BRANCH_TABLE__};
5607 this is a local symbol to permit collecting statistics for many separate
5608 object files. The table is word aligned, and begins with a two-word
5609 header. The first word, initialized to 0, is used in maintaining linked
5610 lists of branch tables. The second word is a count of the number of
5611 entries in the table, which follow immediately: each is a word, pointing
5612 to one of the labels illustrated above.
5616 @c END TEXI2ROFF-KILL
5618 +------------+------------+------------+ ... +------------+
5620 | *NEXT | COUNT: N | *BRLAB 1 | | *BRLAB N |
5622 +------------+------------+------------+ ... +------------+
5624 __BRANCH_TABLE__ layout
5631 \line{\leftskip=0pt\hskip\tableindent
5632 \boxit{2cm}{\tt *NEXT}\boxit{2cm}{\tt COUNT: \it N}\boxit{2cm}{\tt
5633 *BRLAB 1}\ibox{1cm}{\quad\dots}\boxit{2cm}{\tt *BRLAB \it N}\hfil}
5634 \centerline{\it {\tt \_\_BRANCH\_TABLE\_\_} layout}
5636 @c END TEXI2ROFF-KILL
5638 The first word of the header is used to locate multiple branch tables,
5639 since each object file may contain one. Normally the links are
5640 maintained with a call to an initialization routine, placed at the
5641 beginning of each function in the file. The @sc{gnu} C compiler
5642 generates these calls automatically when you give it a @samp{-b} option.
5643 For further details, see the documentation of @samp{gbr960}.
5646 @cindex @code{-no-relax} option, i960
5647 Normally, Compare-and-Branch instructions with targets that require
5648 displacements greater than 13 bits (or that have external targets) are
5649 replaced with the corresponding compare (or @samp{chkbit}) and branch
5650 instructions. You can use the @samp{-no-relax} option to specify that
5651 @code{@value{AS}} should generate errors instead, if the target displacement
5652 is larger than 13 bits.
5654 This option does not affect the Compare-and-Jump instructions; the code
5655 emitted for them is @emph{always} adjusted when necessary (depending on
5656 displacement size), regardless of whether you use @samp{-no-relax}.
5659 @node Floating Point-i960
5660 @section Floating Point
5662 @cindex floating point, i960 (@sc{ieee})
5663 @cindex i960 floating point (@sc{ieee})
5664 @code{@value{AS}} generates @sc{ieee} floating-point numbers for the directives
5665 @samp{.float}, @samp{.double}, @samp{.extended}, and @samp{.single}.
5667 @node Directives-i960
5668 @section i960 Machine Directives
5670 @cindex machine directives, i960
5671 @cindex i960 machine directives
5674 @cindex @code{bss} directive, i960
5675 @item .bss @var{symbol}, @var{length}, @var{align}
5676 Reserve @var{length} bytes in the bss section for a local @var{symbol},
5677 aligned to the power of two specified by @var{align}. @var{length} and
5678 @var{align} must be positive absolute expressions. This directive
5679 differs from @samp{.lcomm} only in that it permits you to specify
5680 an alignment. @xref{Lcomm,,@code{.lcomm}}.
5684 @item .extended @var{flonums}
5685 @cindex @code{extended} directive, i960
5686 @code{.extended} expects zero or more flonums, separated by commas; for
5687 each flonum, @samp{.extended} emits an @sc{ieee} extended-format (80-bit)
5688 floating-point number.
5690 @item .leafproc @var{call-lab}, @var{bal-lab}
5691 @cindex @code{leafproc} directive, i960
5692 You can use the @samp{.leafproc} directive in conjunction with the
5693 optimized @code{callj} instruction to enable faster calls of leaf
5694 procedures. If a procedure is known to call no other procedures, you
5695 may define an entry point that skips procedure prolog code (and that does
5696 not depend on system-supplied saved context), and declare it as the
5697 @var{bal-lab} using @samp{.leafproc}. If the procedure also has an
5698 entry point that goes through the normal prolog, you can specify that
5699 entry point as @var{call-lab}.
5701 A @samp{.leafproc} declaration is meant for use in conjunction with the
5702 optimized call instruction @samp{callj}; the directive records the data
5703 needed later to choose between converting the @samp{callj} into a
5704 @code{bal} or a @code{call}.
5706 @var{call-lab} is optional; if only one argument is present, or if the
5707 two arguments are identical, the single argument is assumed to be the
5708 @code{bal} entry point.
5710 @item .sysproc @var{name}, @var{index}
5711 @cindex @code{sysproc} directive, i960
5712 The @samp{.sysproc} directive defines a name for a system procedure.
5713 After you define it using @samp{.sysproc}, you can use @var{name} to
5714 refer to the system procedure identified by @var{index} when calling
5715 procedures with the optimized call instruction @samp{callj}.
5717 Both arguments are required; @var{index} must be between 0 and 31
5721 @node Opcodes for i960
5722 @section i960 Opcodes
5724 @cindex opcodes, i960
5725 @cindex i960 opcodes
5726 All Intel 960 machine instructions are supported;
5727 @pxref{Options-i960,,i960 Command-line Options} for a discussion of
5728 selecting the instruction subset for a particular 960
5729 architecture.@refill
5731 Some opcodes are processed beyond simply emitting a single corresponding
5732 instruction: @samp{callj}, and Compare-and-Branch or Compare-and-Jump
5733 instructions with target displacements larger than 13 bits.
5736 * callj-i960:: @code{callj}
5737 * Compare-and-branch-i960:: Compare-and-Branch
5741 @subsection @code{callj}
5743 @cindex @code{callj}, i960 pseudo-opcode
5744 @cindex i960 @code{callj} pseudo-opcode
5745 You can write @code{callj} to have the assembler or the linker determine
5746 the most appropriate form of subroutine call: @samp{call},
5747 @samp{bal}, or @samp{calls}. If the assembly source contains
5748 enough information---a @samp{.leafproc} or @samp{.sysproc} directive
5749 defining the operand---then @code{@value{AS}} translates the
5750 @code{callj}; if not, it simply emits the @code{callj}, leaving it
5751 for the linker to resolve.
5753 @node Compare-and-branch-i960
5754 @subsection Compare-and-Branch
5756 @cindex i960 compare/branch instructions
5757 @cindex compare/branch instructions, i960
5758 The 960 architectures provide combined Compare-and-Branch instructions
5759 that permit you to store the branch target in the lower 13 bits of the
5760 instruction word itself. However, if you specify a branch target far
5761 enough away that its address won't fit in 13 bits, the assembler can
5762 either issue an error, or convert your Compare-and-Branch instruction
5763 into separate instructions to do the compare and the branch.
5765 @cindex compare and jump expansions, i960
5766 @cindex i960 compare and jump expansions
5767 Whether @code{@value{AS}} gives an error or expands the instruction depends
5768 on two choices you can make: whether you use the @samp{-no-relax} option,
5769 and whether you use a ``Compare and Branch'' instruction or a ``Compare
5770 and Jump'' instruction. The ``Jump'' instructions are @emph{always}
5771 expanded if necessary; the ``Branch'' instructions are expanded when
5772 necessary @emph{unless} you specify @code{-no-relax}---in which case
5773 @code{@value{AS}} gives an error instead.
5775 These are the Compare-and-Branch instructions, their ``Jump'' variants,
5776 and the instruction pairs they may expand into:
5780 @c END TEXI2ROFF-KILL
5783 Branch Jump Expanded to
5784 ------ ------ ------------
5787 cmpibe cmpije cmpi; be
5788 cmpibg cmpijg cmpi; bg
5789 cmpibge cmpijge cmpi; bge
5790 cmpibl cmpijl cmpi; bl
5791 cmpible cmpijle cmpi; ble
5792 cmpibno cmpijno cmpi; bno
5793 cmpibne cmpijne cmpi; bne
5794 cmpibo cmpijo cmpi; bo
5795 cmpobe cmpoje cmpo; be
5796 cmpobg cmpojg cmpo; bg
5797 cmpobge cmpojge cmpo; bge
5798 cmpobl cmpojl cmpo; bl
5799 cmpoble cmpojle cmpo; ble
5800 cmpobne cmpojne cmpo; bne
5806 \halign{\hfil {\tt #}\quad&\hfil {\tt #}\qquad&{\tt #}\hfil\cr
5807 \omit{\hfil\it Compare and\hfil}\span\omit&\cr
5808 {\it Branch}&{\it Jump}&{\it Expanded to}\cr
5809 bbc& & chkbit; bno\cr
5810 bbs& & chkbit; bo\cr
5811 cmpibe& cmpije& cmpi; be\cr
5812 cmpibg& cmpijg& cmpi; bg\cr
5813 cmpibge& cmpijge& cmpi; bge\cr
5814 cmpibl& cmpijl& cmpi; bl\cr
5815 cmpible& cmpijle& cmpi; ble\cr
5816 cmpibno& cmpijno& cmpi; bno\cr
5817 cmpibne& cmpijne& cmpi; bne\cr
5818 cmpibo& cmpijo& cmpi; bo\cr
5819 cmpobe& cmpoje& cmpo; be\cr
5820 cmpobg& cmpojg& cmpo; bg\cr
5821 cmpobge& cmpojge& cmpo; bge\cr
5822 cmpobl& cmpojl& cmpo; bl\cr
5823 cmpoble& cmpojle& cmpo; ble\cr
5824 cmpobne& cmpojne& cmpo; bne\cr}
5826 @c END TEXI2ROFF-KILL
5832 @node M68K-Dependent
5833 @chapter M680x0 Dependent Features
5836 @node Machine Dependencies
5837 @chapter M680x0 Dependent Features
5840 @cindex M680x0 support
5842 * M68K-Opts:: M680x0 Options
5843 * M68K-Syntax:: Syntax
5844 * M68K-Moto-Syntax:: Motorola Syntax
5845 * M68K-Float:: Floating Point
5846 * M68K-Directives:: 680x0 Machine Directives
5847 * M68K-opcodes:: Opcodes
5851 @section M680x0 Options
5853 @cindex options, M680x0
5854 @cindex M680x0 options
5855 The Motorola 680x0 version of @code{@value{AS}} has two machine dependent options.
5856 One shortens undefined references from 32 to 16 bits, while the
5857 other is used to tell @code{@value{AS}} what kind of machine it is
5860 @cindex @code{-l} option, M680x0
5861 You can use the @samp{-l} option to shorten the size of references to undefined
5862 symbols. If you do not use the @samp{-l} option, references to undefined
5863 symbols are wide enough for a full @code{long} (32 bits). (Since
5864 @code{@value{AS}} cannot know where these symbols end up, @code{@value{AS}} can
5865 only allocate space for the linker to fill in later. Since @code{@value{AS}}
5866 does not know how far away these symbols are, it allocates as much space as it
5867 can.) If you use this option, the references are only one word wide (16 bits).
5868 This may be useful if you want the object file to be as small as possible, and
5869 you know that the relevant symbols are always less than 17 bits away.
5871 @cindex @code{-m68000} and related options
5872 @cindex architecture options, M680x0
5873 @cindex M680x0 architecture options
5874 The 680x0 version of @code{@value{AS}} is most frequently used to assemble
5875 programs for the Motorola MC68020 microprocessor. Occasionally it is
5876 used to assemble programs for the mostly similar, but slightly different
5877 MC68000 or MC68010 microprocessors. You can give @code{@value{AS}} the options
5878 @samp{-m68000}, @samp{-mc68000}, @samp{-m68010}, @samp{-mc68010},
5879 @samp{-m68020}, and @samp{-mc68020} to tell it what processor is the
5886 This syntax for the Motorola 680x0 was developed at @sc{mit}.
5888 @cindex M680x0 syntax
5889 @cindex syntax, M680x0
5890 @cindex M680x0 size modifiers
5891 @cindex size modifiers, M680x0
5892 The 680x0 version of @code{@value{AS}} uses syntax compatible with the Sun
5893 assembler. Intervening periods are ignored; for example, @samp{movl} is
5894 equivalent to @samp{move.l}.
5897 If @code{@value{AS}} is compiled with SUN_ASM_SYNTAX defined, it
5898 also allows Sun-style local labels of the form @samp{1$} through
5902 In the following table @dfn{apc} stands for any of the address
5903 registers (@samp{a0} through @samp{a7}), nothing, (@samp{}), the
5904 Program Counter (@samp{pc}), or the zero-address relative to the
5905 program counter (@samp{zpc}).
5907 @cindex M680x0 addressing modes
5908 @cindex addressing modes, M680x0
5909 The following addressing modes are understood:
5912 @samp{#@var{digits}}
5915 @samp{d0} through @samp{d7}
5917 @item Address Register
5918 @samp{a0} through @samp{a7}@*
5919 @samp{a7} is also known as @samp{sp}, i.e. the Stack Pointer. @code{a6}
5920 is also known as @samp{fp}, the Frame Pointer.
5922 @item Address Register Indirect
5923 @samp{a0@@} through @samp{a7@@}
5925 @item Address Register Postincrement
5926 @samp{a0@@+} through @samp{a7@@+}
5928 @item Address Register Predecrement
5929 @samp{a0@@-} through @samp{a7@@-}
5931 @item Indirect Plus Offset
5932 @samp{@var{apc}@@(@var{digits})}
5935 @samp{@var{apc}@@(@var{digits},@var{register}:@var{size}:@var{scale})}
5937 or @samp{@var{apc}@@(@var{register}:@var{size}:@var{scale})}
5940 @samp{@var{apc}@@(@var{digits})@@(@var{digits},@var{register}:@var{size}:@var{scale})}
5942 or @samp{@var{apc}@@(@var{digits})@@(@var{register}:@var{size}:@var{scale})}
5945 @samp{@var{apc}@@(@var{digits},@var{register}:@var{size}:@var{scale})@@(@var{digits})}
5947 or @samp{@var{apc}@@(@var{register}:@var{size}:@var{scale})@@(@var{digits})}
5949 @item Memory Indirect
5950 @samp{@var{apc}@@(@var{digits})@@(@var{digits})}
5953 @samp{@var{symbol}}, or @samp{@var{digits}}
5955 @c pesch@cygnus.com: gnu, rich concur the following needs careful
5956 @c research before documenting.
5957 , or either of the above followed
5958 by @samp{:b}, @samp{:w}, or @samp{:l}.
5962 For some configurations, especially those where the compiler normally
5963 does not prepend an underscore to the names of user variables, the
5964 assembler requires a @samp{%} before any use of a register name. This
5965 is intended to let the assembler distinguish between user variables and
5966 registers named @samp{a0} through @samp{a7}, and so on. The @samp{%} is
5967 always accepted, but is only required for some configurations, notably
5970 @node M68K-Moto-Syntax
5971 @section Motorola Syntax
5973 @cindex Motorola syntax for the 680x0
5974 @cindex alternate syntax for the 680x0
5976 The standard Motorola syntax for this chip differs from the syntax
5977 already discussed (@pxref{M68K-Syntax,,Syntax}). @code{@value{AS}} can
5978 accept some forms of Motorola syntax for operands, even if @sc{mit} syntax is
5979 used for other operands in the same instruction. The
5980 two kinds of syntax are fully compatible; our support for Motorola syntax is
5981 simply incomplete at present.
5983 @c FIXME! I can't figure out what this means. Surely the "always" is in some
5984 @c restricted context, for instance. It's not necessary for the preceding text
5985 @c to explain this, so just ignore it for now; re-enable someday when someone
5986 @c has time to explain it better.
5987 , because the Motorola syntax never uses
5988 the @samp{@@} character and the @sc{mit} syntax always does, except in
5989 cases where the syntaxes are identical.
5992 @cindex M680x0 syntax
5993 @cindex syntax, M680x0
5994 In particular, you may write or generate M68K assembler with the
5995 following conventions:
5997 (In the following table @dfn{apc} stands for any of the address
5998 registers (@samp{a0} through @samp{a7}), nothing, (@samp{}), the
5999 Program Counter (@samp{pc}), or the zero-address relative to the
6000 program counter (@samp{zpc}).)
6002 @cindex M680x0 addressing modes
6003 @cindex addressing modes, M680x0
6004 The following additional addressing modes are understood:
6006 @item Address Register Indirect
6007 @samp{a0} through @samp{a7}@*
6008 @samp{a7} is also known as @samp{sp}, i.e. the Stack Pointer. @code{a6}
6009 is also known as @samp{fp}, the Frame Pointer.
6011 @item Address Register Postincrement
6012 @samp{(a0)+} through @samp{(a7)+}
6014 @item Address Register Predecrement
6015 @samp{-(a0)} through @samp{-(a7)}
6017 @item Indirect Plus Offset
6018 @samp{@var{digits}(@var{apc})}
6021 @samp{@var{digits}(@var{apc},(@var{register}.@var{size}*@var{scale}))}@*
6022 or @samp{(@var{apc},@var{register}.@var{size}*@var{scale})}@*
6023 In either case, @var{size} and @var{scale} are optional
6024 (@var{scale} defaults to @samp{1}, @var{size} defaults to @samp{l}).
6025 @var{scale} can be @samp{1}, @samp{2}, @samp{4}, or @samp{8}.
6026 @var{size} can be @samp{w} or @samp{l}. @var{scale} is only supported
6027 on the 68020 and greater.
6030 Other, more complex addressing modes permitted in Motorola syntax are not
6034 @section Floating Point
6036 @cindex floating point, M680x0
6037 @cindex M680x0 floating point
6038 @c FIXME is this "not too well tested" crud STILL true?
6039 The floating point code is not too well tested, and may have
6042 Packed decimal (P) format floating literals are not supported.
6043 Feel free to add the code!
6045 The floating point formats generated by directives are these.
6049 @cindex @code{float} directive, M680x0
6050 @code{Single} precision floating point constants.
6053 @cindex @code{double} directive, M680x0
6054 @code{Double} precision floating point constants.
6057 There is no directive to produce regions of memory holding
6058 extended precision numbers, however they can be used as
6059 immediate operands to floating-point instructions. Adding a
6060 directive to create extended precision numbers would not be
6061 hard, but it has not yet seemed necessary.
6063 @node M68K-Directives
6064 @section 680x0 Machine Directives
6066 @cindex M680x0 directives
6067 @cindex directives, M680x0
6068 In order to be compatible with the Sun assembler the 680x0 assembler
6069 understands the following directives.
6073 @cindex @code{data1} directive, M680x0
6074 This directive is identical to a @code{.data 1} directive.
6077 @cindex @code{data2} directive, M680x0
6078 This directive is identical to a @code{.data 2} directive.
6081 @cindex @code{even} directive, M680x0
6082 This directive is identical to a @code{.align 1} directive.
6083 @c Is this true? does it work???
6086 @cindex @code{skip} directive, M680x0
6087 This directive is identical to a @code{.space} directive.
6094 @cindex M680x0 opcodes
6095 @cindex opcodes, M680x0
6096 @cindex instruction set, M680x0
6097 @c pesch@cygnus.com: I don't see any point in the following
6098 @c paragraph. Bugs are bugs; how does saying this
6101 Danger: Several bugs have been found in the opcode table (and
6102 fixed). More bugs may exist. Be careful when using obscure
6107 * M68K-Branch:: Branch Improvement
6108 * M68K-Chars:: Special Characters
6112 @subsection Branch Improvement
6114 @cindex pseudo-opcodes, M680x0
6115 @cindex M680x0 pseudo-opcodes
6116 @cindex branch improvement, M680x0
6117 @cindex M680x0 branch improvement
6118 Certain pseudo opcodes are permitted for branch instructions.
6119 They expand to the shortest branch instruction that reach the
6120 target. Generally these mnemonics are made by substituting @samp{j} for
6121 @samp{b} at the start of a Motorola mnemonic.
6123 The following table summarizes the pseudo-operations. A @code{*} flags
6124 cases that are more fully described after the table:
6128 +-------------------------------------------------
6130 Pseudo-Op |BYTE WORD LONG LONG non-PC relative
6131 +-------------------------------------------------
6132 jbsr |bsrs bsr bsrl jsr jsr
6133 jra |bras bra bral jmp jmp
6134 * jXX |bXXs bXX bXXl bNXs;jmpl bNXs;jmp
6135 * dbXX |dbXX dbXX dbXX; bra; jmpl
6136 * fjXX |fbXXw fbXXw fbXXl fbNXw;jmp
6139 NX: negative of condition XX
6142 @center @code{*}---see full description below
6147 These are the simplest jump pseudo-operations; they always map to one
6148 particular machine instruction, depending on the displacement to the
6152 Here, @samp{j@var{XX}} stands for an entire family of pseudo-operations,
6153 where @var{XX} is a conditional branch or condition-code test. The full
6154 list of pseudo-ops in this family is:
6156 jhi jls jcc jcs jne jeq jvc
6157 jvs jpl jmi jge jlt jgt jle
6160 For the cases of non-PC relative displacements and long displacements on
6161 the 68000 or 68010, @code{@value{AS}} issues a longer code fragment in terms of
6162 @var{NX}, the opposite condition to @var{XX}. For example, for the
6163 non-PC relative case:
6175 The full family of pseudo-operations covered here is
6177 dbhi dbls dbcc dbcs dbne dbeq dbvc
6178 dbvs dbpl dbmi dbge dblt dbgt dble
6182 Other than for word and byte displacements, when the source reads
6183 @samp{db@var{XX} foo}, @code{@value{AS}} emits
6192 This family includes
6194 fjne fjeq fjge fjlt fjgt fjle fjf
6195 fjt fjgl fjgle fjnge fjngl fjngle fjngt
6196 fjnle fjnlt fjoge fjogl fjogt fjole fjolt
6197 fjor fjseq fjsf fjsne fjst fjueq fjuge
6198 fjugt fjule fjult fjun
6201 For branch targets that are not PC relative, @code{@value{AS}} emits
6207 when it encounters @samp{fj@var{XX} foo}.
6212 @subsection Special Characters
6214 @cindex special characters, M680x0
6215 @cindex M680x0 immediate character
6216 @cindex immediate character, M680x0
6217 @cindex M680x0 line comment character
6218 @cindex line comment character, M680x0
6219 @cindex comments, M680x0
6220 The immediate character is @samp{#} for Sun compatibility. The
6221 line-comment character is @samp{|}. If a @samp{#} appears at the
6222 beginning of a line, it is treated as a comment unless it looks like
6223 @samp{# line file}, in which case it is treated normally.
6227 @c FIXME! Stop ignoring when filled in.
6232 The 32x32 version of @code{@value{AS}} accepts a @samp{-m32032} option to
6233 specify thiat it is compiling for a 32032 processor, or a
6234 @samp{-m32532} to specify that it is compiling for a 32532 option.
6235 The default (if neither is specified) is chosen when the assembler
6239 I don't know anything about the 32x32 syntax assembled by
6240 @code{@value{AS}}. Someone who undersands the processor (I've never seen
6241 one) and the possible syntaxes should write this section.
6243 @section Floating Point
6244 The 32x32 uses @sc{ieee} floating point numbers, but @code{@value{AS}}
6245 only creates single or double precision values. I don't know if the
6246 32x32 understands extended precision numbers.
6248 @section 32x32 Machine Directives
6249 The 32x32 has no machine dependent directives.
6255 @node Sparc-Dependent
6256 @chapter SPARC Dependent Features
6259 @node Machine Dependencies
6260 @chapter SPARC Dependent Features
6263 @cindex SPARC support
6265 * Sparc-Opts:: Options
6266 * Sparc-Float:: Floating Point
6267 * Sparc-Directives:: Sparc Machine Directives
6273 @cindex options for SPARC
6274 @cindex SPARC options
6275 @cindex architectures, SPARC
6276 @cindex SPARC architectures
6277 The SPARC chip family includes several successive levels (or other
6278 variants) of chip, using the same core instruction set, but including
6279 a few additional instructions at each level.
6281 By default, @code{@value{AS}} assumes the core instruction set (SPARC
6282 v6), but ``bumps'' the architecture level as needed: it switches to
6283 successively higher architectures as it encounters instructions that
6284 only exist in the higher levels.
6287 @item -Av6 | -Av7 | -Av8 | -Asparclite
6292 Use one of the @samp{-A} options to select one of the SPARC
6293 architectures explicitly. If you select an architecture explicitly,
6294 @code{@value{AS}} reports a fatal error if it encounters an instruction
6295 or feature requiring a higher level.
6298 Permit the assembler to ``bump'' the architecture level as required, but
6299 warn whenever it is necessary to switch to another level.
6303 @c FIXME: (sparc) Fill in "syntax" section!
6304 @c subsection syntax
6305 I don't know anything about Sparc syntax. Someone who does
6306 will have to write this section.
6310 @section Floating Point
6312 @cindex floating point, SPARC (@sc{ieee})
6313 @cindex SPARC floating point (@sc{ieee})
6314 The Sparc uses @sc{ieee} floating-point numbers.
6316 @node Sparc-Directives
6317 @section Sparc Machine Directives
6319 @cindex SPARC machine directives
6320 @cindex machine directives, SPARC
6321 The Sparc version of @code{@value{AS}} supports the following additional
6326 @cindex @code{common} directive, SPARC
6327 This must be followed by a symbol name, a positive number, and
6328 @code{"bss"}. This behaves somewhat like @code{.comm}, but the
6329 syntax is different.
6332 @cindex @code{half} directive, SPARC
6333 This is functionally identical to @code{.short}.
6336 @cindex @code{proc} directive, SPARC
6337 This directive is ignored. Any text following it on the same
6338 line is also ignored.
6341 @cindex @code{reserve} directive, SPARC
6342 This must be followed by a symbol name, a positive number, and
6343 @code{"bss"}. This behaves somewhat like @code{.lcomm}, but the
6344 syntax is different.
6347 @cindex @code{seg} directive, SPARC
6348 This must be followed by @code{"text"}, @code{"data"}, or
6349 @code{"data1"}. It behaves like @code{.text}, @code{.data}, or
6353 @cindex @code{skip} directive, SPARC
6354 This is functionally identical to the @code{.space} directive.
6357 @cindex @code{word} directive, SPARC
6358 On the Sparc, the .word directive produces 32 bit values,
6359 instead of the 16 bit values it produces on many other machines.
6366 @node i386-Dependent
6367 @chapter 80386 Dependent Features
6370 @node Machine Dependencies
6371 @chapter 80386 Dependent Features
6374 @cindex i386 support
6375 @cindex i80306 support
6377 * i386-Options:: Options
6378 * i386-Syntax:: AT&T Syntax versus Intel Syntax
6379 * i386-Opcodes:: Opcode Naming
6380 * i386-Regs:: Register Naming
6381 * i386-prefixes:: Opcode Prefixes
6382 * i386-Memory:: Memory References
6383 * i386-jumps:: Handling of Jump Instructions
6384 * i386-Float:: Floating Point
6385 * i386-Notes:: Notes
6391 @cindex options for i386 (none)
6392 @cindex i386 options (none)
6393 The 80386 has no machine dependent options.
6396 @section AT&T Syntax versus Intel Syntax
6398 @cindex i386 syntax compatibility
6399 @cindex syntax compatibility, i386
6400 In order to maintain compatibility with the output of @code{@value{GCC}},
6401 @code{@value{AS}} supports AT&T System V/386 assembler syntax. This is quite
6402 different from Intel syntax. We mention these differences because
6403 almost all 80386 documents used only Intel syntax. Notable differences
6404 between the two syntaxes are:
6408 @cindex immediate operands, i386
6409 @cindex i386 immediate operands
6410 @cindex register operands, i386
6411 @cindex i386 register operands
6412 @cindex jump/call operands, i386
6413 @cindex i386 jump/call operands
6414 @cindex operand delimiters, i386
6415 AT&T immediate operands are preceded by @samp{$}; Intel immediate
6416 operands are undelimited (Intel @samp{push 4} is AT&T @samp{pushl $4}).
6417 AT&T register operands are preceded by @samp{%}; Intel register operands
6418 are undelimited. AT&T absolute (as opposed to PC relative) jump/call
6419 operands are prefixed by @samp{*}; they are undelimited in Intel syntax.
6422 @cindex i386 source, destination operands
6423 @cindex source, destination operands; i386
6424 AT&T and Intel syntax use the opposite order for source and destination
6425 operands. Intel @samp{add eax, 4} is @samp{addl $4, %eax}. The
6426 @samp{source, dest} convention is maintained for compatibility with
6427 previous Unix assemblers.
6430 @cindex opcode suffixes, i386
6431 @cindex sizes operands, i386
6432 @cindex i386 size suffixes
6433 In AT&T syntax the size of memory operands is determined from the last
6434 character of the opcode name. Opcode suffixes of @samp{b}, @samp{w},
6435 and @samp{l} specify byte (8-bit), word (16-bit), and long (32-bit)
6436 memory references. Intel syntax accomplishes this by prefixes memory
6437 operands (@emph{not} the opcodes themselves) with @samp{byte ptr},
6438 @samp{word ptr}, and @samp{dword ptr}. Thus, Intel @samp{mov al, byte
6439 ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T syntax.
6442 @cindex return instructions, i386
6443 @cindex i386 jump, call, return
6444 Immediate form long jumps and calls are
6445 @samp{lcall/ljmp $@var{section}, $@var{offset}} in AT&T syntax; the
6447 @samp{call/jmp far @var{section}:@var{offset}}. Also, the far return
6449 is @samp{lret $@var{stack-adjust}} in AT&T syntax; Intel syntax is
6450 @samp{ret far @var{stack-adjust}}.
6453 @cindex sections, i386
6454 @cindex i386 sections
6455 The AT&T assembler does not provide support for multiple section
6456 programs. Unix style systems expect all programs to be single sections.
6460 @section Opcode Naming
6462 @cindex i386 opcode naming
6463 @cindex opcode naming, i386
6464 Opcode names are suffixed with one character modifiers which specify the
6465 size of operands. The letters @samp{b}, @samp{w}, and @samp{l} specify
6466 byte, word, and long operands. If no suffix is specified by an
6467 instruction and it contains no memory operands then @code{@value{AS}} tries to
6468 fill in the missing suffix based on the destination register operand
6469 (the last one by convention). Thus, @samp{mov %ax, %bx} is equivalent
6470 to @samp{movw %ax, %bx}; also, @samp{mov $1, %bx} is equivalent to
6471 @samp{movw $1, %bx}. Note that this is incompatible with the AT&T Unix
6472 assembler which assumes that a missing opcode suffix implies long
6473 operand size. (This incompatibility does not affect compiler output
6474 since compilers always explicitly specify the opcode suffix.)
6476 Almost all opcodes have the same names in AT&T and Intel format. There
6477 are a few exceptions. The sign extend and zero extend instructions need
6478 two sizes to specify them. They need a size to sign/zero extend
6479 @emph{from} and a size to zero extend @emph{to}. This is accomplished
6480 by using two opcode suffixes in AT&T syntax. Base names for sign extend
6481 and zero extend are @samp{movs@dots{}} and @samp{movz@dots{}} in AT&T
6482 syntax (@samp{movsx} and @samp{movzx} in Intel syntax). The opcode
6483 suffixes are tacked on to this base name, the @emph{from} suffix before
6484 the @emph{to} suffix. Thus, @samp{movsbl %al, %edx} is AT&T syntax for
6485 ``move sign extend @emph{from} %al @emph{to} %edx.'' Possible suffixes,
6486 thus, are @samp{bl} (from byte to long), @samp{bw} (from byte to word),
6487 and @samp{wl} (from word to long).
6489 @cindex conversion instructions, i386
6490 @cindex i386 conversion instructions
6491 The Intel-syntax conversion instructions
6495 @samp{cbw} --- sign-extend byte in @samp{%al} to word in @samp{%ax},
6498 @samp{cwde} --- sign-extend word in @samp{%ax} to long in @samp{%eax},
6501 @samp{cwd} --- sign-extend word in @samp{%ax} to long in @samp{%dx:%ax},
6504 @samp{cdq} --- sign-extend dword in @samp{%eax} to quad in @samp{%edx:%eax},
6508 are called @samp{cbtw}, @samp{cwtl}, @samp{cwtd}, and @samp{cltd} in
6509 AT&T naming. @code{@value{AS}} accepts either naming for these instructions.
6511 @cindex jump instructions, i386
6512 @cindex call instructions, i386
6513 Far call/jump instructions are @samp{lcall} and @samp{ljmp} in
6514 AT&T syntax, but are @samp{call far} and @samp{jump far} in Intel
6518 @section Register Naming
6520 @cindex i386 registers
6521 @cindex registers, i386
6522 Register operands are always prefixes with @samp{%}. The 80386 registers
6527 the 8 32-bit registers @samp{%eax} (the accumulator), @samp{%ebx},
6528 @samp{%ecx}, @samp{%edx}, @samp{%edi}, @samp{%esi}, @samp{%ebp} (the
6529 frame pointer), and @samp{%esp} (the stack pointer).
6532 the 8 16-bit low-ends of these: @samp{%ax}, @samp{%bx}, @samp{%cx},
6533 @samp{%dx}, @samp{%di}, @samp{%si}, @samp{%bp}, and @samp{%sp}.
6536 the 8 8-bit registers: @samp{%ah}, @samp{%al}, @samp{%bh},
6537 @samp{%bl}, @samp{%ch}, @samp{%cl}, @samp{%dh}, and @samp{%dl} (These
6538 are the high-bytes and low-bytes of @samp{%ax}, @samp{%bx},
6539 @samp{%cx}, and @samp{%dx})
6542 the 6 section registers @samp{%cs} (code section), @samp{%ds}
6543 (data section), @samp{%ss} (stack section), @samp{%es}, @samp{%fs},
6547 the 3 processor control registers @samp{%cr0}, @samp{%cr2}, and
6551 the 6 debug registers @samp{%db0}, @samp{%db1}, @samp{%db2},
6552 @samp{%db3}, @samp{%db6}, and @samp{%db7}.
6555 the 2 test registers @samp{%tr6} and @samp{%tr7}.
6558 the 8 floating point register stack @samp{%st} or equivalently
6559 @samp{%st(0)}, @samp{%st(1)}, @samp{%st(2)}, @samp{%st(3)},
6560 @samp{%st(4)}, @samp{%st(5)}, @samp{%st(6)}, and @samp{%st(7)}.
6564 @section Opcode Prefixes
6566 @cindex i386 opcode prefixes
6567 @cindex opcode prefixes, i386
6568 @cindex prefixes, i386
6569 Opcode prefixes are used to modify the following opcode. They are used
6570 to repeat string instructions, to provide section overrides, to perform
6571 bus lock operations, and to give operand and address size (16-bit
6572 operands are specified in an instruction by prefixing what would
6573 normally be 32-bit operands with a ``operand size'' opcode prefix).
6574 Opcode prefixes are usually given as single-line instructions with no
6575 operands, and must directly precede the instruction they act upon. For
6576 example, the @samp{scas} (scan string) instruction is repeated with:
6582 Here is a list of opcode prefixes:
6586 @cindex section override prefixes, i386
6587 Section override prefixes @samp{cs}, @samp{ds}, @samp{ss}, @samp{es},
6588 @samp{fs}, @samp{gs}. These are automatically added by specifying
6589 using the @var{section}:@var{memory-operand} form for memory references.
6592 @cindex size prefixes, i386
6593 Operand/Address size prefixes @samp{data16} and @samp{addr16}
6594 change 32-bit operands/addresses into 16-bit operands/addresses. Note
6595 that 16-bit addressing modes (i.e. 8086 and 80286 addressing modes)
6596 are not supported (yet).
6599 @cindex bus lock prefixes, i386
6600 @cindex inhibiting interrupts, i386
6601 The bus lock prefix @samp{lock} inhibits interrupts during
6602 execution of the instruction it precedes. (This is only valid with
6603 certain instructions; see a 80386 manual for details).
6606 @cindex coprocessor wait, i386
6607 The wait for coprocessor prefix @samp{wait} waits for the
6608 coprocessor to complete the current instruction. This should never be
6609 needed for the 80386/80387 combination.
6612 @cindex repeat prefixes, i386
6613 The @samp{rep}, @samp{repe}, and @samp{repne} prefixes are added
6614 to string instructions to make them repeat @samp{%ecx} times.
6618 @section Memory References
6620 @cindex i386 memory references
6621 @cindex memory references, i386
6622 An Intel syntax indirect memory reference of the form
6625 @var{section}:[@var{base} + @var{index}*@var{scale} + @var{disp}]
6629 is translated into the AT&T syntax
6632 @var{section}:@var{disp}(@var{base}, @var{index}, @var{scale})
6636 where @var{base} and @var{index} are the optional 32-bit base and
6637 index registers, @var{disp} is the optional displacement, and
6638 @var{scale}, taking the values 1, 2, 4, and 8, multiplies @var{index}
6639 to calculate the address of the operand. If no @var{scale} is
6640 specified, @var{scale} is taken to be 1. @var{section} specifies the
6641 optional section register for the memory operand, and may override the
6642 default section register (see a 80386 manual for section register
6643 defaults). Note that section overrides in AT&T syntax @emph{must} have
6644 be preceded by a @samp{%}. If you specify a section override which
6645 coincides with the default section register, @code{@value{AS}} does @emph{not}
6646 output any section register override prefixes to assemble the given
6647 instruction. Thus, section overrides can be specified to emphasize which
6648 section register is used for a given memory operand.
6650 Here are some examples of Intel and AT&T style memory references:
6653 @item AT&T: @samp{-4(%ebp)}, Intel: @samp{[ebp - 4]}
6654 @var{base} is @samp{%ebp}; @var{disp} is @samp{-4}. @var{section} is
6655 missing, and the default section is used (@samp{%ss} for addressing with
6656 @samp{%ebp} as the base register). @var{index}, @var{scale} are both missing.
6658 @item AT&T: @samp{foo(,%eax,4)}, Intel: @samp{[foo + eax*4]}
6659 @var{index} is @samp{%eax} (scaled by a @var{scale} 4); @var{disp} is
6660 @samp{foo}. All other fields are missing. The section register here
6661 defaults to @samp{%ds}.
6663 @item AT&T: @samp{foo(,1)}; Intel @samp{[foo]}
6664 This uses the value pointed to by @samp{foo} as a memory operand.
6665 Note that @var{base} and @var{index} are both missing, but there is only
6666 @emph{one} @samp{,}. This is a syntactic exception.
6668 @item AT&T: @samp{%gs:foo}; Intel @samp{gs:foo}
6669 This selects the contents of the variable @samp{foo} with section
6670 register @var{section} being @samp{%gs}.
6673 Absolute (as opposed to PC relative) call and jump operands must be
6674 prefixed with @samp{*}. If no @samp{*} is specified, @code{@value{AS}}
6675 always chooses PC relative addressing for jump/call labels.
6677 Any instruction that has a memory operand @emph{must} specify its size (byte,
6678 word, or long) with an opcode suffix (@samp{b}, @samp{w}, or @samp{l},
6682 @section Handling of Jump Instructions
6684 @cindex jump optimization, i386
6685 @cindex i386 jump optimization
6686 Jump instructions are always optimized to use the smallest possible
6687 displacements. This is accomplished by using byte (8-bit) displacement
6688 jumps whenever the target is sufficiently close. If a byte displacement
6689 is insufficient a long (32-bit) displacement is used. We do not support
6690 word (16-bit) displacement jumps (i.e. prefixing the jump instruction
6691 with the @samp{addr16} opcode prefix), since the 80386 insists upon masking
6692 @samp{%eip} to 16 bits after the word displacement is added.
6694 Note that the @samp{jcxz}, @samp{jecxz}, @samp{loop}, @samp{loopz},
6695 @samp{loope}, @samp{loopnz} and @samp{loopne} instructions only come in byte
6696 displacements, so that if you use these instructions (@code{@value{GCC}} does
6697 not use them) you may get an error message (and incorrect code). The AT&T
6698 80386 assembler tries to get around this problem by expanding @samp{jcxz foo}
6709 @section Floating Point
6711 @cindex i386 floating point
6712 @cindex floating point, i386
6713 All 80387 floating point types except packed BCD are supported.
6714 (BCD support may be added without much difficulty). These data
6715 types are 16-, 32-, and 64- bit integers, and single (32-bit),
6716 double (64-bit), and extended (80-bit) precision floating point.
6717 Each supported type has an opcode suffix and a constructor
6718 associated with it. Opcode suffixes specify operand's data
6719 types. Constructors build these data types into memory.
6723 @cindex @code{float} directive, i386
6724 @cindex @code{single} directive, i386
6725 @cindex @code{double} directive, i386
6726 @cindex @code{tfloat} directive, i386
6727 Floating point constructors are @samp{.float} or @samp{.single},
6728 @samp{.double}, and @samp{.tfloat} for 32-, 64-, and 80-bit formats.
6729 These correspond to opcode suffixes @samp{s}, @samp{l}, and @samp{t}.
6730 @samp{t} stands for temporary real, and that the 80387 only supports
6731 this format via the @samp{fldt} (load temporary real to stack top) and
6732 @samp{fstpt} (store temporary real and pop stack) instructions.
6735 @cindex @code{word} directive, i386
6736 @cindex @code{long} directive, i386
6737 @cindex @code{int} directive, i386
6738 @cindex @code{quad} directive, i386
6739 Integer constructors are @samp{.word}, @samp{.long} or @samp{.int}, and
6740 @samp{.quad} for the 16-, 32-, and 64-bit integer formats. The corresponding
6741 opcode suffixes are @samp{s} (single), @samp{l} (long), and @samp{q}
6742 (quad). As with the temporary real format the 64-bit @samp{q} format is
6743 only present in the @samp{fildq} (load quad integer to stack top) and
6744 @samp{fistpq} (store quad integer and pop stack) instructions.
6747 Register to register operations do not require opcode suffixes,
6748 so that @samp{fst %st, %st(1)} is equivalent to @samp{fstl %st, %st(1)}.
6750 @cindex i386 @code{fwait} instruction
6751 @cindex @code{fwait instruction}, i386
6752 Since the 80387 automatically synchronizes with the 80386 @samp{fwait}
6753 instructions are almost never needed (this is not the case for the
6754 80286/80287 and 8086/8087 combinations). Therefore, @code{@value{AS}} suppresses
6755 the @samp{fwait} instruction whenever it is implicitly selected by one
6756 of the @samp{fn@dots{}} instructions. For example, @samp{fsave} and
6757 @samp{fnsave} are treated identically. In general, all the @samp{fn@dots{}}
6758 instructions are made equivalent to @samp{f@dots{}} instructions. If
6759 @samp{fwait} is desired it must be explicitly coded.
6764 @cindex i386 @code{mul}, @code{imul} instructions
6765 @cindex @code{mul} instruction, i386
6766 @cindex @code{imul} instruction, i386
6767 There is some trickery concerning the @samp{mul} and @samp{imul}
6768 instructions that deserves mention. The 16-, 32-, and 64-bit expanding
6769 multiplies (base opcode @samp{0xf6}; extension 4 for @samp{mul} and 5
6770 for @samp{imul}) can be output only in the one operand form. Thus,
6771 @samp{imul %ebx, %eax} does @emph{not} select the expanding multiply;
6772 the expanding multiply would clobber the @samp{%edx} register, and this
6773 would confuse @code{@value{GCC}} output. Use @samp{imul %ebx} to get the
6774 64-bit product in @samp{%edx:%eax}.
6776 We have added a two operand form of @samp{imul} when the first operand
6777 is an immediate mode expression and the second operand is a register.
6778 This is just a shorthand, so that, multiplying @samp{%eax} by 69, for
6779 example, can be done with @samp{imul $69, %eax} rather than @samp{imul
6786 @node Z8000-Dependent
6787 @chapter Z8000 Dependent Features
6790 @node Machine Dependencies
6791 @chapter Z8000 Dependent Features
6794 @cindex Z8000 support
6795 The Z8000 @value{AS} supports both members of the Z8000 family: the
6796 unsegmented Z8002, with 16 bit addresses, and the segmented Z8001 with
6799 When the assembler is in unsegmented mode (specified with the
6800 @code{unsegm} directive), an address takes up one word (16 bit)
6801 sized register. When the assembler is in segmented mode (specified with
6802 the @code{segm} directive), a 24-bit address takes up a long (32 bit)
6803 register. @xref{Z8000 Directives,,Assembler Directives for the Z8000},
6804 for a list of other Z8000 specific assembler directives.
6807 * Z8000 Options:: No special command-line options for Z8000
6808 * Z8000 Syntax:: Assembler syntax for the Z8000
6809 * Z8000 Directives:: Special directives for the Z8000
6810 * Z8000 Opcodes:: Opcodes
6816 @cindex Z8000 options
6817 @cindex options, Z8000
6818 @code{@value{AS}} has no additional command-line options for the Zilog
6824 * Z8000-Chars:: Special Characters
6825 * Z8000-Regs:: Register Names
6826 * Z8000-Addressing:: Addressing Modes
6830 @subsection Special Characters
6832 @cindex line comment character, Z8000
6833 @cindex Z8000 line comment character
6834 @samp{!} is the line comment character.
6836 @cindex line separator, Z8000
6837 @cindex statement separator, Z8000
6838 @cindex Z8000 line separator
6839 You can use @samp{;} instead of a newline to separate statements.
6842 @subsection Register Names
6844 @cindex Z8000 registers
6845 @cindex registers, Z8000
6846 The Z8000 has sixteen 16 bit registers, numbered 0 to 15. You can refer
6847 to different sized groups of registers by register number, with the
6848 prefix @samp{r} for 16 bit registers, @samp{rr} for 32 bit registers and
6849 @samp{rq} for 64 bit registers. You can also refer to the contents of
6850 the first eight (of the sixteen 16 bit registers) by bytes. They are
6851 named @samp{r@var{n}h} and @samp{r@var{n}l}.
6854 @exdent @emph{byte registers}
6855 r0l r0h r1h r1l r2h r2l r3h r3l
6856 r4h r4l r5h r5l r6h r6l r7h r7l
6858 @exdent @emph{word registers}
6859 r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r13 r14 r15
6861 @exdent @emph{long word registers}
6862 rr0 rr2 rr4 rr6 rr8 rr10 rr12 rr14
6864 @exdent @emph{quad word registers}
6868 @node Z8000-Addressing
6869 @subsection Addressing Modes
6871 @cindex addressing modes, Z8000
6872 @cindex Z800 addressing modes
6873 @value{AS} understands the following addressing modes for the Z8000:
6883 Direct: the 16 bit or 24 bit address (depending on whether the assembler
6884 is in segmented or unsegmented mode) of the operand is in the instruction.
6886 @item address(r@var{n})
6887 Indexed: the 16 or 24 bit address is added to the 16 bit register to produce
6888 the final address in memory of the operand.
6890 @item r@var{n}(#@var{imm})
6891 Base Address: the 16 or 24 bit register is added to the 16 bit sign
6892 extended immediate displacement to produce the final address in memory
6895 @item r@var{n}(r@var{m})
6896 Base Index: the 16 or 24 bit register r@var{n} is added to the sign
6897 extended 16 bit index register r@var{m} to produce the final address in
6898 memory of the operand.
6901 Immediate data @var{xx}.
6904 @node Z8000 Directives
6905 @section Assembler Directives for the Z8000
6907 @cindex Z8000 directives
6908 @cindex directives, Z8000
6909 The Z8000 port of @value{AS} includes these additional assembler directives,
6910 for compatibility with other Z8000 assemblers. As shown, these do not
6911 begin with @samp{.} (unlike the ordinary @value{AS} directives).
6916 Generates code for the segmented Z8001.
6920 Generates code for the unsegmented Z8002.
6924 Synonym for @code{.file}
6928 Synonum for @code{.global}
6932 Synonym for @code{.word}
6936 Synonym for @code{.long}
6940 Synonym for @code{.byte}
6944 Assemble a string. @code{sval} expects one string literal, delimited by
6945 single quotes. It assembles each byte of the string into consecutive
6946 addresses. You can use the escape sequence @samp{%@var{xx}} (where
6947 @var{xx} represents a two-digit hexadecimal number) to represent the
6948 character whose @sc{ascii} value is @var{xx}. Use this feature to
6949 describe single quote and other characters that may not appear in string
6950 literals as themselves. For example, the C statement @w{@samp{char *a =
6951 "he said \"it's 50% off\"";}} is represented in Z8000 assembly language
6952 (shown with the assembler output in hex at the left) as
6956 @let@nonarrowing=@comment
6959 68652073 sval 'he said %22it%27s 50%25 off%22%00'
6972 synonym for @code{.section}
6976 synonym for @code{.space}
6980 synonym for @code{.align 1}
6986 @cindex Z8000 opcode summary
6987 @cindex opcode summary, Z8000
6988 @cindex mnemonics, Z8000
6989 @cindex instruction summary, Z8000
6990 For detailed information on the Z8000 machine instruction set, see
6991 @cite{Z8000 Technical Manual}.
6994 @c this table, due to the multi-col faking and hardcoded order, looks silly
6995 @c except in smallbook. See comments below "@set SMALL" near top of this file.
6997 The following table summarizes the opcodes and their arguments:
7000 @let@nonarrowing=@comment
7004 rs @r{16 bit source register}
7005 rd @r{16 bit destination register}
7006 rbs @r{8 bit source register}
7007 rbd @r{8 bit destination register}
7008 rrs @r{32 bit source register}
7009 rrd @r{32 bit destination register}
7010 rqs @r{64 bit source register}
7011 rqd @r{64 bit destination register}
7012 addr @r{16/24 bit address}
7013 imm @r{immediate data}
7015 adc rd,rs clrb addr cpsir @@rd,@@rs,rr,cc
7016 adcb rbd,rbs clrb addr(rd) cpsirb @@rd,@@rs,rr,cc
7017 add rd,@@rs clrb rbd dab rbd
7018 add rd,addr com @@rd dbjnz rbd,disp7
7019 add rd,addr(rs) com addr dec @@rd,imm4m1
7020 add rd,imm16 com addr(rd) dec addr(rd),imm4m1
7021 add rd,rs com rd dec addr,imm4m1
7022 addb rbd,@@rs comb @@rd dec rd,imm4m1
7023 addb rbd,addr comb addr decb @@rd,imm4m1
7024 addb rbd,addr(rs) comb addr(rd) decb addr(rd),imm4m1
7025 addb rbd,imm8 comb rbd decb addr,imm4m1
7026 addb rbd,rbs comflg flags decb rbd,imm4m1
7027 addl rrd,@@rs cp @@rd,imm16 di i2
7028 addl rrd,addr cp addr(rd),imm16 div rrd,@@rs
7029 addl rrd,addr(rs) cp addr,imm16 div rrd,addr
7030 addl rrd,imm32 cp rd,@@rs div rrd,addr(rs)
7031 addl rrd,rrs cp rd,addr div rrd,imm16
7032 and rd,@@rs cp rd,addr(rs) div rrd,rs
7033 and rd,addr cp rd,imm16 divl rqd,@@rs
7034 and rd,addr(rs) cp rd,rs divl rqd,addr
7035 and rd,imm16 cpb @@rd,imm8 divl rqd,addr(rs)
7036 and rd,rs cpb addr(rd),imm8 divl rqd,imm32
7037 andb rbd,@@rs cpb addr,imm8 divl rqd,rrs
7038 andb rbd,addr cpb rbd,@@rs djnz rd,disp7
7039 andb rbd,addr(rs) cpb rbd,addr ei i2
7040 andb rbd,imm8 cpb rbd,addr(rs) ex rd,@@rs
7041 andb rbd,rbs cpb rbd,imm8 ex rd,addr
7042 bit @@rd,imm4 cpb rbd,rbs ex rd,addr(rs)
7043 bit addr(rd),imm4 cpd rd,@@rs,rr,cc ex rd,rs
7044 bit addr,imm4 cpdb rbd,@@rs,rr,cc exb rbd,@@rs
7045 bit rd,imm4 cpdr rd,@@rs,rr,cc exb rbd,addr
7046 bit rd,rs cpdrb rbd,@@rs,rr,cc exb rbd,addr(rs)
7047 bitb @@rd,imm4 cpi rd,@@rs,rr,cc exb rbd,rbs
7048 bitb addr(rd),imm4 cpib rbd,@@rs,rr,cc ext0e imm8
7049 bitb addr,imm4 cpir rd,@@rs,rr,cc ext0f imm8
7050 bitb rbd,imm4 cpirb rbd,@@rs,rr,cc ext8e imm8
7051 bitb rbd,rs cpl rrd,@@rs ext8f imm8
7052 bpt cpl rrd,addr exts rrd
7053 call @@rd cpl rrd,addr(rs) extsb rd
7054 call addr cpl rrd,imm32 extsl rqd
7055 call addr(rd) cpl rrd,rrs halt
7056 calr disp12 cpsd @@rd,@@rs,rr,cc in rd,@@rs
7057 clr @@rd cpsdb @@rd,@@rs,rr,cc in rd,imm16
7058 clr addr cpsdr @@rd,@@rs,rr,cc inb rbd,@@rs
7059 clr addr(rd) cpsdrb @@rd,@@rs,rr,cc inb rbd,imm16
7060 clr rd cpsi @@rd,@@rs,rr,cc inc @@rd,imm4m1
7061 clrb @@rd cpsib @@rd,@@rs,rr,cc inc addr(rd),imm4m1
7062 inc addr,imm4m1 ldb rbd,rs(rx) mult rrd,addr(rs)
7063 inc rd,imm4m1 ldb rd(imm16),rbs mult rrd,imm16
7064 incb @@rd,imm4m1 ldb rd(rx),rbs mult rrd,rs
7065 incb addr(rd),imm4m1 ldctl ctrl,rs multl rqd,@@rs
7066 incb addr,imm4m1 ldctl rd,ctrl multl rqd,addr
7067 incb rbd,imm4m1 ldd @@rs,@@rd,rr multl rqd,addr(rs)
7068 ind @@rd,@@rs,ra lddb @@rs,@@rd,rr multl rqd,imm32
7069 indb @@rd,@@rs,rba lddr @@rs,@@rd,rr multl rqd,rrs
7070 inib @@rd,@@rs,ra lddrb @@rs,@@rd,rr neg @@rd
7071 inibr @@rd,@@rs,ra ldi @@rd,@@rs,rr neg addr
7072 iret ldib @@rd,@@rs,rr neg addr(rd)
7073 jp cc,@@rd ldir @@rd,@@rs,rr neg rd
7074 jp cc,addr ldirb @@rd,@@rs,rr negb @@rd
7075 jp cc,addr(rd) ldk rd,imm4 negb addr
7076 jr cc,disp8 ldl @@rd,rrs negb addr(rd)
7077 ld @@rd,imm16 ldl addr(rd),rrs negb rbd
7078 ld @@rd,rs ldl addr,rrs nop
7079 ld addr(rd),imm16 ldl rd(imm16),rrs or rd,@@rs
7080 ld addr(rd),rs ldl rd(rx),rrs or rd,addr
7081 ld addr,imm16 ldl rrd,@@rs or rd,addr(rs)
7082 ld addr,rs ldl rrd,addr or rd,imm16
7083 ld rd(imm16),rs ldl rrd,addr(rs) or rd,rs
7084 ld rd(rx),rs ldl rrd,imm32 orb rbd,@@rs
7085 ld rd,@@rs ldl rrd,rrs orb rbd,addr
7086 ld rd,addr ldl rrd,rs(imm16) orb rbd,addr(rs)
7087 ld rd,addr(rs) ldl rrd,rs(rx) orb rbd,imm8
7088 ld rd,imm16 ldm @@rd,rs,n orb rbd,rbs
7089 ld rd,rs ldm addr(rd),rs,n out @@rd,rs
7090 ld rd,rs(imm16) ldm addr,rs,n out imm16,rs
7091 ld rd,rs(rx) ldm rd,@@rs,n outb @@rd,rbs
7092 lda rd,addr ldm rd,addr(rs),n outb imm16,rbs
7093 lda rd,addr(rs) ldm rd,addr,n outd @@rd,@@rs,ra
7094 lda rd,rs(imm16) ldps @@rs outdb @@rd,@@rs,rba
7095 lda rd,rs(rx) ldps addr outib @@rd,@@rs,ra
7096 ldar rd,disp16 ldps addr(rs) outibr @@rd,@@rs,ra
7097 ldb @@rd,imm8 ldr disp16,rs pop @@rd,@@rs
7098 ldb @@rd,rbs ldr rd,disp16 pop addr(rd),@@rs
7099 ldb addr(rd),imm8 ldrb disp16,rbs pop addr,@@rs
7100 ldb addr(rd),rbs ldrb rbd,disp16 pop rd,@@rs
7101 ldb addr,imm8 ldrl disp16,rrs popl @@rd,@@rs
7102 ldb addr,rbs ldrl rrd,disp16 popl addr(rd),@@rs
7103 ldb rbd,@@rs mbit popl addr,@@rs
7104 ldb rbd,addr mreq rd popl rrd,@@rs
7105 ldb rbd,addr(rs) mres push @@rd,@@rs
7106 ldb rbd,imm8 mset push @@rd,addr
7107 ldb rbd,rbs mult rrd,@@rs push @@rd,addr(rs)
7108 ldb rbd,rs(imm16) mult rrd,addr push @@rd,imm16
7109 push @@rd,rs set addr,imm4 subl rrd,imm32
7110 pushl @@rd,@@rs set rd,imm4 subl rrd,rrs
7111 pushl @@rd,addr set rd,rs tcc cc,rd
7112 pushl @@rd,addr(rs) setb @@rd,imm4 tccb cc,rbd
7113 pushl @@rd,rrs setb addr(rd),imm4 test @@rd
7114 res @@rd,imm4 setb addr,imm4 test addr
7115 res addr(rd),imm4 setb rbd,imm4 test addr(rd)
7116 res addr,imm4 setb rbd,rs test rd
7117 res rd,imm4 setflg imm4 testb @@rd
7118 res rd,rs sinb rbd,imm16 testb addr
7119 resb @@rd,imm4 sinb rd,imm16 testb addr(rd)
7120 resb addr(rd),imm4 sind @@rd,@@rs,ra testb rbd
7121 resb addr,imm4 sindb @@rd,@@rs,rba testl @@rd
7122 resb rbd,imm4 sinib @@rd,@@rs,ra testl addr
7123 resb rbd,rs sinibr @@rd,@@rs,ra testl addr(rd)
7124 resflg imm4 sla rd,imm8 testl rrd
7125 ret cc slab rbd,imm8 trdb @@rd,@@rs,rba
7126 rl rd,imm1or2 slal rrd,imm8 trdrb @@rd,@@rs,rba
7127 rlb rbd,imm1or2 sll rd,imm8 trib @@rd,@@rs,rbr
7128 rlc rd,imm1or2 sllb rbd,imm8 trirb @@rd,@@rs,rbr
7129 rlcb rbd,imm1or2 slll rrd,imm8 trtdrb @@ra,@@rb,rbr
7130 rldb rbb,rba sout imm16,rs trtib @@ra,@@rb,rr
7131 rr rd,imm1or2 soutb imm16,rbs trtirb @@ra,@@rb,rbr
7132 rrb rbd,imm1or2 soutd @@rd,@@rs,ra trtrb @@ra,@@rb,rbr
7133 rrc rd,imm1or2 soutdb @@rd,@@rs,rba tset @@rd
7134 rrcb rbd,imm1or2 soutib @@rd,@@rs,ra tset addr
7135 rrdb rbb,rba soutibr @@rd,@@rs,ra tset addr(rd)
7136 rsvd36 sra rd,imm8 tset rd
7137 rsvd38 srab rbd,imm8 tsetb @@rd
7138 rsvd78 sral rrd,imm8 tsetb addr
7139 rsvd7e srl rd,imm8 tsetb addr(rd)
7140 rsvd9d srlb rbd,imm8 tsetb rbd
7141 rsvd9f srll rrd,imm8 xor rd,@@rs
7142 rsvdb9 sub rd,@@rs xor rd,addr
7143 rsvdbf sub rd,addr xor rd,addr(rs)
7144 sbc rd,rs sub rd,addr(rs) xor rd,imm16
7145 sbcb rbd,rbs sub rd,imm16 xor rd,rs
7146 sc imm8 sub rd,rs xorb rbd,@@rs
7147 sda rd,rs subb rbd,@@rs xorb rbd,addr
7148 sdab rbd,rs subb rbd,addr xorb rbd,addr(rs)
7149 sdal rrd,rs subb rbd,addr(rs) xorb rbd,imm8
7150 sdl rd,rs subb rbd,imm8 xorb rbd,rbs
7151 sdlb rbd,rs subb rbd,rbs xorb rbd,rbs
7152 sdll rrd,rs subl rrd,@@rs
7153 set @@rd,imm4 subl rrd,addr
7154 set addr(rd),imm4 subl rrd,addr(rs)
7166 @node MIPS-Dependent
7167 @chapter MIPS Dependent Features
7170 @node Machine Dependencies
7171 @chapter MIPS Dependent Features
7178 @sc{gnu} @code{@value{AS}} for @sc{mips} architectures supports the @sc{mips}
7179 @sc{r2000}, @sc{r3000}, @sc{r4000} and @sc{r6000} processors. For information
7180 about the @sc{mips} instruction set, see @cite{MIPS RISC Architecture}, by Kane
7181 and Heindrich (Prentice-Hall). For an overview of @sc{mips} assembly
7182 conventions, see ``Appendix D: Assembly Language Programming'' in the same
7186 * MIPS Opts:: Assembler options
7187 * MIPS Object:: ECOFF object code
7188 * MIPS Stabs:: Directives for debugging information
7189 * MIPS ISA:: Directives to override the ISA level
7193 @section Assembler options
7195 The @sc{mips} configurations of @sc{gnu} @code{@value{AS}} support these
7199 @cindex @code{-G} option (MIPS)
7201 This option sets the largest size of an object that can be referenced
7202 implicitly with the @code{gp} register. It is only accepted for targets
7203 that use @sc{ecoff} format. The default value is 8.
7205 @cindex @code{-EB} option (MIPS)
7206 @cindex @code{-EL} option (MIPS)
7207 @cindex MIPS big-endian output
7208 @cindex MIPS little-endian output
7209 @cindex big-endian output, MIPS
7210 @cindex little-endian output, MIPS
7213 Any @sc{mips} configuration of @code{@value{AS}} can select big-endian or
7214 little-endian output at run time (unlike the other @sc{gnu} development
7215 tools, which must be configured for one or the other). Use @samp{-EB}
7216 to select big-endian output, and @samp{-EL} for little-endian.
7218 @cindex MIPS architecture options
7222 Generate code for a particular MIPS Instruction Set Architecture level.
7223 @samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
7224 @samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
7225 processor. You can also switch instruction sets during the assembly; see
7226 @ref{MIPS ISA,, Directives to override the ISA level}.
7230 Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
7231 the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
7232 instructions around accesses to the @samp{HI} and @samp{LO} registers.
7233 @samp{-no-m4650} turns off this option.
7235 @item -mcpu=@var{CPU}
7236 Generate code for a particular MIPS cpu. This has little effect on the
7237 assembler, but it is passed by @code{@value{GCC}}.
7239 @cindex @code{-nocpp} ignored (MIPS)
7241 This option is ignored. It is accepted for command-line compatibility with
7242 other assemblers, which use it to turn off C style preprocessing. With
7243 @sc{gnu} @code{@value{AS}}, there is no need for @samp{-nocpp}, because the
7244 @sc{gnu} assembler itself never runs the C preprocessor.
7248 @c FIXME! (1) reflect these options (next item too) in option summaries;
7249 @c (2) stop teasing, say _which_ instructions expanded _how_.
7250 @code{@value{AS}} automatically macro expands certain division and
7251 multiplication instructions to check for overflow and division by zero. This
7252 option causes @code{@value{AS}} to generate code to take a trap exception
7253 rather than a break exception when an error is detected. The trap instructions
7254 are only supported at Instruction Set Architecture level 2 and higher.
7258 Generate code to take a break exception rather than a trap exception when an
7259 error is detected. This is the default.
7263 @section MIPS ECOFF object code
7265 @cindex ECOFF sections
7266 @cindex MIPS ECOFF sections
7267 Assembling for a @sc{mips} @sc{ecoff} target supports some additional sections
7268 besides the usual @code{.text}, @code{.data} and @code{.bss}. The
7269 additional sections are @code{.rdata}, used for read-only data,
7270 @code{.sdata}, used for small data, and @code{.sbss}, used for small
7273 @cindex small objects, MIPS ECOFF
7274 @cindex @code{gp} register, MIPS
7275 When assembling for @sc{ecoff}, the assembler uses the @code{$gp} (@code{$28})
7276 register to form the address of a ``small object''. Any object in the
7277 @code{.sdata} or @code{.sbss} sections is considered ``small'' in this sense.
7278 For external objects, or for objects in the @code{.bss} section, you can use
7279 the @code{@value{GCC}} @samp{-G} option to control the size of objects addressed via
7280 @code{$gp}; the default value is 8, meaning that a reference to any object
7281 eight bytes or smaller uses @code{$gp}. Passing @samp{-G 0} to
7282 @code{@value{AS}} prevents it from using the @code{$gp} register on the basis
7283 of object size (but the assembler uses @code{$gp} for objects in @code{.sdata}
7284 or @code{sbss} in any case). The size of an object in the @code{.bss} section
7285 is set by the @code{.comm} or @code{.lcomm} directive that defines it. The
7286 size of an external object may be set with the @code{.extern} directive. For
7287 example, @samp{.extern sym,4} declares that the object at @code{sym} is 4 bytes
7288 in length, whie leaving @code{sym} otherwise undefined.
7290 Using small @sc{ecoff} objects requires linker support, and assumes that the
7291 @code{$gp} register is correctly initialized (normally done automatically by
7292 the startup code). @sc{mips} @sc{ecoff} assembly code must not modify the
7293 @code{$gp} register.
7296 @section Directives for debugging information
7298 @cindex MIPS debugging directives
7299 @sc{mips} @sc{ecoff} @code{@value{AS}} supports several directives used for
7300 generating debugging information which are not support by traditional @sc{mips}
7301 assemblers. These are @code{.def}, @code{.endef}, @code{.dim}, @code{.file},
7302 @code{.scl}, @code{.size}, @code{.tag}, @code{.type}, @code{.val},
7303 @code{.stabd}, @code{.stabn}, and @code{.stabs}. The debugging information
7304 generated by the three @code{.stab} directives can only be read by @sc{gdb},
7305 not by traditional @sc{mips} debuggers (this enhancement is required to fully
7306 support C++ debugging). These directives are primarily used by compilers, not
7307 assembly language programmers!
7310 @section Directives to override the ISA level
7312 @cindex MIPS ISA override
7313 @kindex @code{.set mips@var{n}}
7314 @sc{gnu} @code{@value{AS}} supports an additional directive to change the
7315 @sc{mips} Instruction Set Architecture level on the fly: @code{.set
7316 mips@var{n}}. @var{n} should be a number from 0 to 3. A value from 1 to 3
7317 makes the assembler accept instructions for the corresponding @sc{isa} level,
7318 from that point on in the assembly. @code{.set mips@var{n}} affects not only
7319 which instructions are permitted, but also how certain macros are expanded.
7320 @code{.set mips0} restores the @sc{isa} level to its original level: either the
7321 level you selected with command line options, or the default for your
7322 configuration. You can use this feature to permit specific @sc{r4000}
7323 instructions while assembling in 32 bit mode. Use this directive with care!
7325 Traditional @sc{mips} assemblers do not support this directive.
7329 @c reverse effect of @down at top of generic Machine-Dep chapter
7333 @node Acknowledgements
7334 @chapter Acknowledgements
7336 If you have contributed to @code{@value{AS}} and your name isn't listed here,
7337 it is not meant as a slight. We just don't know about it. Send mail to the
7338 maintainer, and we'll correct the situation. Currently (January 1994), the
7339 maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
7341 Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any more
7344 Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
7345 information and the 68k series machines, most of the preprocessing pass, and
7346 extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
7348 K. Richard Pixley maintained GAS for a while, adding various enhancements and
7349 many bug fixes, including merging support for several processors, breaking GAS
7350 up to handle multiple object file format back ends (including heavy rewrite,
7351 testing, an integration of the coff and b.out back ends), adding configuration
7352 including heavy testing and verification of cross assemblers and file splits
7353 and renaming, converted GAS to strictly ANSI C including full prototypes, added
7354 support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
7355 port (including considerable amounts of reverse engineering), a SPARC opcode
7356 file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
7357 assertions and made them work, much other reorganization, cleanup, and lint.
7359 Ken Raeburn wrote the high-level BFD interface code to replace most of the code
7360 in format-specific I/O modules.
7362 The original VMS support was contributed by David L. Kashtan. Eric Youngdale
7363 has done much work with it since.
7365 The Intel 80386 machine description was written by Eliot Dresselhaus.
7367 Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
7369 The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
7370 University and Torbjorn Granlund of the Swedish Institute of Computer Science.
7372 Keith Knowles at the Open Software Foundation wrote the original MIPS back end
7373 (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
7374 (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
7375 support a.out format.
7377 Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
7378 tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
7379 Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
7380 use BFD for some low-level operations, for use with the H8/300 and AMD 29k
7383 John Gilmore built the AMD 29000 support, added @code{.include} support, and
7384 simplified the configuration of which versions accept which directives. He
7385 updated the 68k machine description so that Motorola's opcodes always produced
7386 fixed-size instructions (e.g. @code{jsr}), while synthetic instructions
7387 remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
7388 cross-compilation support, and one bug in relaxation that took a week and
7389 required the proverbial one-bit fix.
7391 Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
7392 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
7393 added support for MIPS ECOFF and ELF targets, and made a few other minor
7396 Steve Chamberlain made @code{@value{AS}} able to generate listings.
7398 Hewlett-Packard contributed support for the HP9000/300.
7400 Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
7401 along with a fairly extensive HPPA testsuite (for both SOM and ELF object
7402 formats). This work was supported by both the Center for Software Science at
7403 the University of Utah and Cygnus Support.
7405 Support for ELF format files has been worked on by Mark Eichin of Cygnus
7406 Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
7407 Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
7408 Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
7409 and some initial 64-bit support).
7411 Several engineers at Cygnus Support have also provided many small bug fixes and
7412 configuration enhancements.
7414 Many others have contributed large or small bugfixes and enhancements. If
7415 you have contributed significant work and are not mentioned on this list, and
7416 want to be, let us know. Some of the history has been lost; we are not
7417 intentionally leaving anyone out.