-\input texinfo
-@c $Id$
+_dnl__ -*-Texinfo-*-
+_dnl__ Copyright (c) 1991 1992 Free Software Foundation, Inc.
+_dnl__ $Id$
+\input texinfo @c -*-Texinfo-*-
+@c Copyright (c) 1991 1992 Free Software Foundation, Inc.
+@c %**start of header
+@setfilename _AS__.info
_if__(_GENERIC__)
-@setfilename as.info
+@settitle Using _AS__
_fi__(_GENERIC__)
-_if__(_A29K__ && !_GENERIC__)
-@setfilename as-29k.info
-_fi__(_A29K__ && !_GENERIC__)
-_if__(_H8__ && !_GENERIC__)
-@setfilename h8-300.info
-_fi__(_H8__ && !_GENERIC__)
-_if__(_I960__ && !_GENERIC__)
-@setfilename as-960.info
-_fi__(_I960__ && !_GENERIC__)
-_if__(_M680X0__ && !_GENERIC__)
-@setfilename as-m680x0.info
-_fi__(_M680X0__ && !_GENERIC__)
+_if__(!_GENERIC__)
+@settitle Using _AS__ (_HOST__)
+_fi__(!_GENERIC__)
+@setchapternewpage odd
+@c @smallbook
+@c @cropmarks
+@c %**end of header
+
+@finalout
+@syncodeindex ky cp
+
_if__(0)
NOTE: this manual is marked up for preprocessing with a collection
before either tex- or info- formatting: for example,
m4 pretex.m4 none.m4 m680x0.m4 as.texinfo >as-680x0.texinfo
will produce (assuming your path finds either GNU or SysV m4; Berkeley
-won't do) a file suitable for formatting. See the text in "pretex.m4"
-for a fuller explanation (and the macro definitions).
+won't do) a file, configured for the M680x0 version of GAS, suitable for
+formatting. See the text in "pretex.m4" for a fuller explanation (and
+the macro definitions).
_fi__(0)
@c
-@synindex ky cp
@ifinfo
This file documents the GNU Assembler "_AS__".
included in a translation approved by the Free Software Foundation
instead of in the original English.
@end ifinfo
-@iftex
-@finalout
-@c @smallbook
-@end iftex
-@setchapternewpage odd
-_if__(_GENERIC__)
-@settitle Using _AS__
-_fi__(_GENERIC__)
-_if__(!_GENERIC__)
-@settitle Using _AS__ (_HOST__)
-_fi__(!_GENERIC__)
+
@titlepage
@title Using _AS__
@subtitle The GNU Assembler
@subtitle for the _HOST__ family
_fi__(!_GENERIC__)
@sp 1
-@subtitle March 1991
+@subtitle January 1992
@sp 1
@sp 13
The Free Software Foundation Inc. thanks The Nice Computer
* Symbols:: Symbols
* Expressions:: Expressions
* Pseudo Ops:: Assembler Directives
-* Machine Dependent:: Machine Dependent Features
+* _MACH_DEP__:: Machine Dependent Features
* Copying:: GNU GENERAL PUBLIC LICENSE
+* Index:: Index
@end menu
@node Overview, Invoking, Top, Top
_fi__(!_GENERIC__)
@end iftex
-@heading Invoking @code{_AS__}
-
+@cindex invocation summary
+@cindex option summary
+@cindex summary of options
Here is a brief summary of how to invoke @code{_AS__}. For details,
@pxref{Invoking,,Comand-Line Options}.
@c We don't use deffn and friends for the following because they seem
@c to be limited to one line for the header.
@smallexample
- _AS__ [ -D ] [ -f ] [ -I @var{path} ] [ -k ] [ -L ]
+ _AS__ [ -a | -al | -as ] [ -D ] [ -f ]
+ [ -I @var{path} ] [ -k ] [ -L ]
[ -o @var{objfile} ] [ -R ] [ -v ] [ -w ]
_if__(_A29K__)
@c am29k has no machine-dependent assembler options
@end smallexample
@table @code
+@item -a | -al | -as
+Turn on assembly listings; @samp{-al}, listing only, @samp{-as}, symbols
+only, @samp{-a}, everything.
@item -D
This option is accepted only for script compatibility with calls to
Add @var{path} to the search list for @code{.include} directives
@item -k
-_if__((!_GENERIC__) && _DIFFTABKLUG__)
+_if__((!_GENERIC__) && !_DIFFTABKLUG__)
This option is accepted but has no effect on the _HOST__ family.
-_fi__((!_GENERIC__) && _DIFFTABKLUG__)
-_if__(_GENERIC__)
+_fi__((!_GENERIC__) && !_DIFFTABKLUG__)
+_if__(_GENERIC__ || _DIFFTABKLUG__)
Issue warnings when difference tables altered for long displacements.
-_fi__(_GENERIC__)
+_fi__(_GENERIC__ || _DIFFTABKLUG__)
@item -L
Keep (in symbol table) local symbols, starting with @samp{L}
_if__(_I960__)
@item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
+_if__(_GENERIC__)
+(When configured for Intel 960).
+_fi__(_GENERIC__)
Specify which variant of the 960 architecture is the target.
@item -b
+_if__(_GENERIC__)
+(When configured for Intel 960).
+_fi__(_GENERIC__)
Add code to collect statistics about branches taken.
@item -norelax
-Do not alter compare-and-branch instructions for long displaements;
+_if__(_GENERIC__)
+(When configured for Intel 960).
+_fi__(_GENERIC__)
+Do not alter compare-and-branch instructions for long displacements;
error if necessary.
_fi__(_I960__)
_fi__(_M680X0__)
@item -- | @var{files} @dots{}
-Source files to assemble, or standard input
+Standard input, or source files to assemble
@end table
@menu
@node Manual, GNU Assembler, Overview, Overview
@section Structure of this Manual
-This document is intended to describe what you need to know to use
-@code{_AS__}. We cover the syntax expected in source files, including
+
+@cindex manual, structure and purpose
+This manual is intended to describe what you need to know to use
+@sc{gnu} @code{_AS__}. We cover the syntax expected in source files, including
notation for symbols, constants, and expressions; the directives that
@code{_AS__} understands; and of course how to invoke @code{_AS__}.
configuration of @code{_AS__}, including assembler directives.
_fi__(!_GENERIC__)
_if__(_GENERIC__)
-This document also describes some of the machine-dependent features of
+This manual also describes some of the machine-dependent features of
various flavors of the assembler.
_fi__(_GENERIC__)
_if__(_INTERNALS__)
-This document also describes how the assembler works internally, and
+This manual also describes how the assembler works internally, and
provides some information that may be useful to people attempting to
port the assembler to another machine.
_fi__(_INTERNALS__)
@refill
+@cindex machine instructions (not covered)
On the other hand, this manual is @emph{not} intended as an introduction
to programming in assembly language---let alone programming in general!
In a similar vein, we make no attempt to introduce the machine
architecture; we do @emph{not} describe the instruction set, standard
mnemonics, registers or addressing modes that are standard to a
-particular architecture. You may want to consult the manufacturer's
+particular architecture.
+_if__(_GENERIC__)
+You may want to consult the manufacturer's
machine architecture manual for this information.
+_fi__(_GENERIC__)
+_if__(_H8__&&!_GENERIC__)
+For information on the H8/300 machine instruction set, see @cite{H8/300
+Series Programming Manual} (Hitachi ADE--602--025).
+_fi__(_H8__&&!_GENERIC__)
@c I think this is premature---pesch@cygnus.com, 17jan1991
@ignore
-Throughout this document, we assume that you are running @dfn{GNU},
+Throughout this manual, we assume that you are running @dfn{GNU},
the portable operating system from the @dfn{Free Software
Foundation, Inc.}. This restricts our attention to certain kinds of
computer (in particular, the kinds of computers that GNU can run on);
@node GNU Assembler, Object Formats, Manual, Overview
@section _AS__, the GNU Assembler
+
GNU @code{as} is really a family of assemblers.
_if__(!_GENERIC__)
-This manual describes @samp{_AS__}, a member of that family which is
+This manual describes @code{_AS__}, a member of that family which is
configured for the _HOST__ architectures.
_fi__(!_GENERIC__)
If you use (or have used) the GNU assembler on one architecture, you
including object file formats, most assembler directives (often called
@dfn{pseudo-ops)} and assembler syntax.@refill
+_if__(_GENERIC__||!_H8__)
+@cindex purpose of @sc{gnu} @code{_AS__}
@code{_AS__} is primarily intended to assemble the output of the GNU C
compiler @code{_GCC__} for use by the linker @code{_LD__}. Nevertheless,
we've tried to make @code{_AS__} assemble correctly everything that the native
assembler would.
+_fi__(_GENERIC__||!_H8__)
_if__(_VAX__)
Any exceptions are documented explicitly (@pxref{_MACH_DEP__}).
_fi__(_VAX__)
@node Object Formats, Command Line, GNU Assembler, Overview
@section Object File Formats
+
+@cindex object file format
The GNU assembler can be configured to produce several alternative
object file formats. For the most part, this does not affect how you
write assembly language programs; but directives for debugging symbols
@node Command Line, Input Files, Object Formats, Overview
@section Command Line
+@cindex command line conventions
After the program name @code{_AS__}, the command line may contain
-options and file names. Options may be in any order, and may be
+options and file names. Options may appear in any order, and may be
before, after, or between file names. The order of file names is
significant.
+@cindex standard input, as input file
+@kindex --
@file{--} (two hyphens) by itself names the standard input file
explicitly, as one of the files for @code{_AS__} to assemble.
+@cindex options, command line
Except for @samp{--} any command line argument that begins with a
hyphen (@samp{-}) is an option. Each option changes the behavior of
@code{_AS__}. No option changes the way another option works. An
@node Input Files, Object, Command Line, Overview
@section Input Files
+@cindex input
+@cindex source program
+@cindex files, input
We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
describe the program input to one run of @code{_AS__}. The program may
be in one or more files; how the source is partitioned into files
command line argument (in any position) that has no special meaning
is taken to be an input file name.
-If @code{_AS__} is given no file names it attempts to read one input file
+If you give @code{_AS__} no file names it attempts to read one input file
from the @code{_AS__} standard input, which is normally your terminal. You
may have to type @key{ctl-D} to tell @code{_AS__} there is no more program
to assemble.
file.
@subheading Filenames and Line-numbers
-There are two ways of locating a line in the input file (or files) and both
-are used in reporting error messages. One way refers to a line
+
+@cindex input file linenumbers
+@cindex line numbers, in input files
+There are two ways of locating a line in the input file (or files) and
+either may be used in reporting error messages. One way refers to a line
number in a physical file; the other refers to a line number in a
-``logical'' file.
+``logical'' file. @xref{Errors, ,Error and Warning Messages}.
@dfn{Physical files} are those files named in the command line given
to @code{_AS__}.
@node Object, Errors, Input Files, Overview
@section Output (Object) File
+
+@cindex object file
+@cindex output file
+@kindex a.out
+@kindex .o
Every time you run @code{_AS__} it produces an output file, which is
your assembly language program translated into numbers. This file
is the object file, named @code{a.out} unless you tell @code{_AS__} to
runnable program.
@c This may still work, but hasn't been tested.
+@cindex linker
+@kindex ld
The object file is meant for input to the linker @code{_LD__}. It contains
assembled program code, information to help @code{_LD__} integrate
the assembled program into a runnable file, and (optionally) symbolic
information for the debugger.
-@comment link above to some info file(s) like the description of a.out.
-@comment don't forget to describe GNU info as well as Unix lossage.
+@c link above to some info file(s) like the description of a.out.
+@c don't forget to describe GNU info as well as Unix lossage.
@node Errors, , Object, Overview
@section Error and Warning Messages
+@cindex error messsages
+@cindex warning messages
+@cindex messages from @code{_AS__}
@code{_AS__} may write warnings and error messages to the standard error
-file (usually your terminal). This should not happen when @code{_AS__} is
-run automatically by a compiler. Warnings report an assumption made so
+file (usually your terminal). This should not happen when a compiler
+runs @code{_AS__} automatically. Warnings report an assumption made so
that @code{_AS__} could keep assembling a flawed program; errors report a
grave problem that stops the assembly.
+@cindex format of warning messages
Warning messages have the format
+
@smallexample
file_name:@b{NNN}:Warning Message Text
@end smallexample
+
@noindent
+@cindex line numbers, in warnings/errors
(where @b{NNN} is a line number). If a logical file name has
been given (@pxref{App-File,,@code{.app-file}}) it is used for the filename, otherwise the
name of the current input file is used. If a logical line number was
message text is intended to be self explanatory (in the grand Unix
tradition). @refill
+@cindex format of error messages
Error messages have the format
@smallexample
file_name:@b{NNN}:FATAL:Error Message Text
@node Invoking, Syntax, Overview, Top
@chapter Command-Line Options
-This section describes command-line options available in @emph{all}
+
+@cindex options, all versions of @code{_AS__}
+This chapter describes command-line options available in @emph{all}
versions of the GNU assembler; @pxref{_MACH_DEP__}, for options specific
_if__(!_GENERIC__)
to the _HOST__.
to particular machine architectures.
_fi__(_GENERIC__)
-@subsection @code{-D}
+@section @code{-a}, @code{-al}, @code{-as}
+
+@kindex -a
+@kindex -al
+@kindex -as
+@cindex listings, enabling
+@cindex assembly listings, enabling
+These options enable listing output from the assembler. @samp{-a} by
+itself requests all listing output; @samp{-al} requests only the
+output-program listing, and @samp{-as} requests only a symbol table
+listing.
+
+Once you have specified one of these options, you can further control
+listing output and its appearance using the directives @code{.list},
+@code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
+@code{.sbttl}.
+
+If you do not request listing output with one of the @samp{-a} options, the
+listing-control directives have no effect.
+
+@section @code{-D}
+
+@kindex -D
This option has no effect whatsoever, but it is accepted to make it more
likely that scripts written for other assemblers will also work with
@code{_AS__}.
-@subsection Work Faster: @code{-f}
+@section Work Faster: @code{-f}
+
+@kindex -f
+@cindex trusted compiler
+@cindex faster processing (@code{-f})
@samp{-f} should only be used when assembling programs written by a
(trusted) compiler. @samp{-f} stops the assembler from pre-processing
-the input file(s) before assembling them.
+the input file(s) before assembling them. @xref{Pre-processing,
+,Pre-processing}.
+
@quotation
@emph{Warning:} if the files actually need to be pre-processed (if they
contain comments, for example), @code{_AS__} will not work correctly if
@samp{-f} is used.
@end quotation
-@subsection @code{.include} search path: @code{-I} @var{path}
+@section @code{.include} search path: @code{-I} @var{path}
+
+@kindex -I @var{path}
+@cindex paths for @code{.include}
+@cindex search path for @code{.include}
+@cindex @code{include} directive search path
Use this option to add a @var{path} to the list of directories
@code{_AS__} will search for files specified in @code{.include}
directives (@pxref{Include,,@code{.include}}). You may use @code{-I} as
searches any @samp{-I} directories in the same order as they were
specified (left to right) on the command line.
-@subsection Difference Tables: @code{-k}
+@section Difference Tables: @code{-k}
+
+@kindex -k
_if__((!_GENERIC__) && (!_DIFFTABKLUG__))
On the _HOST__ family, this option is allowed, but has no effect. It is
permitted for compatibility with the GNU assembler on other platforms,
_fi__((!_GENERIC__) && (!_DIFFTABKLUG__))
_if__(_GENERIC__ || _DIFFTABKLUG__ )
+@cindex difference tables, warning
+@cindex warning for altered difference tables
@code{_AS__} sometimes alters the code emitted for directives of the form
@samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
You can use the @samp{-k} option if you want a warning issued when this
is done.
_fi__(_GENERIC__ || _DIFFTABKLUG__ )
-@subsection Include Local Labels: @code{-L}
+@section Include Local Labels: @code{-L}
+
+@kindex -L
+@cindex local labels, retaining in output
Labels beginning with @samp{L} (upper case only) are called @dfn{local
labels}. @xref{Symbol Names}. Normally you don't see such labels when
debugging, because they are intended for the use of programs (like
in the object file. Usually if you do this you also tell the linker
@code{_LD__} to preserve symbols whose names begin with @samp{L}.
-@subsection Name the Object File: @code{-o}
+@section Name the Object File: @code{-o}
+
+@kindex -o
+@cindex naming object file
+@cindex object file name
There is always one object file output when you run @code{_AS__}. By
default it has the name @file{a.out}. You use this option (which
takes exactly one filename) to give the object file a different name.
Whatever the object file is called, @code{_AS__} will overwrite any
existing file of the same name.
-@subsection Join Data and Text Sections: @code{-R}
-_if__(_COFF__)
-This option is only useful if you use sections named @samp{.text} and
-@samp{.data}.
-_fi__(_COFF__)
+@section Join Data and Text Sections: @code{-R}
+
+@kindex -R
+@cindex data and text sections, joining
+@cindex text and data sections, joining
+@cindex joining text and data sections
+@cindex merging text and data sections
@code{-R} tells @code{_AS__} to write the object file as if all
data-section data lives in the text section. This is only done at
the very last moment: your binary data are the same, but data
data section). We refrain from doing this simply for compatibility with
older versions of @code{_AS__}. In future, @code{-R} may work this way.
-@subsection Announce Version: @code{-v}
+_if__(_COFF__)
+When @code{_AS__} is configured for COFF output,
+this option is only useful if you use sections named @samp{.text} and
+@samp{.data}.
+_fi__(_COFF__)
+
+@section Announce Version: @code{-v}
+
+@kindex -v
+@kindex -version
+@cindex @code{_AS__} version
+@cindex version of @code{_AS__}
You can find out what version of as is running by including the
option @samp{-v} (which you can also spell as @samp{-version}) on the
command line.
-@subsection Suppress Warnings: @code{-W}
+@section Suppress Warnings: @code{-W}
+
+@kindex -W
+@cindex suppressing warnings
+@cindex warnings, suppressing
@code{_AS__} should never give a warning or error message when
assembling compiler output. But programs written by people often
cause @code{_AS__} to give a warning that a particular assumption was
@node Syntax, Sections, Invoking, Top
@chapter Syntax
+
+@cindex machine-independent syntax
+@cindex syntax, machine-independent
This chapter describes the machine-independent syntax allowed in a
source file. @code{_AS__} syntax is similar to what many other assemblers
use; it is inspired in BSD 4.2
@end menu
@node Pre-processing, Whitespace, Syntax, Syntax
-@section Pre-processing
+@section Pre-Processing
+@cindex preprocessing
The pre-processor:
@itemize @bullet
+@cindex whitespace, removed by preprocessor
@item
adjusts and removes extra whitespace. It leaves one space or tab before
the keywords on a line, and turns any other whitespace on the line into
a single space.
+@cindex comments, removed by preprocessor
@item
removes all comments, replacing them with a single space, or an
appropriate number of newlines.
+@cindex constants, converted by preprocessor
@item
converts character constants into the appropriate numeric values.
@end itemize
cannot be used in the portions of the input text that are not
pre-processed.
+@cindex turning preprocessing on and off
+@cindex preprocessing, turning on and off
+@kindex #NO_APP
+@kindex #APP
If the first line of an input file is @code{#NO_APP} or the @samp{-f}
option is given, the input file will not be pre-processed. Within such
an input file, parts of the file can be pre-processed by putting a line
@node Whitespace, Comments, Pre-processing, Syntax
@section Whitespace
+
+@cindex whitespace
@dfn{Whitespace} is one or more blanks or tabs, in any order.
Whitespace is used to separate symbols, and to make programs neater for
people to read. Unless within character constants
@node Comments, Symbol Intro, Whitespace, Syntax
@section Comments
+
+@cindex comments
There are two ways of rendering comments to @code{_AS__}. In both
cases the comment is equivalent to one space.
/* This sort of comment does not nest. */
@end smallexample
+@cindex line comment character
Anything from the @dfn{line comment} character to the next newline
is considered a comment and is ignored. The line comment character is
_if__(_VAX__)
a line, while the other will always begin a comment.
_fi__(_GENERIC__)
-To be compatible with past assemblers a special interpretation is
+@kindex #
+@cindex lines starting with @code{#}
+@cindex logical line numbers
+To be compatible with past assemblers, a special interpretation is
given to lines that begin with @samp{#}. Following the @samp{#} an
absolute expression (@pxref{Expressions}) is expected: this will be
the logical line number of the @b{next} line. Then a string
@node Symbol Intro, Statements, Comments, Syntax
@section Symbols
+
+@cindex symbols
+@cindex characters used in symbols
A @dfn{symbol} is one or more characters chosen from the set of all
letters (both upper and lower case), digits and
_if__(!_H8__)
delimited by characters not in that set, or by the beginning of a file
(since the source program must end with a newline, the end of a file is
not a possible symbol delimiter). @xref{Symbols}.
+@cindex length of symbols
@node Statements, Constants, Symbol Intro, Syntax
@section Statements
+
+@cindex statements, structure of
+@cindex line separator character
+@cindex statement separator character
_if__(!_GENERIC__)
_if__(!(_A29K__||_H8__))
A @dfn{statement} ends at a newline character (@samp{\n}) or at a
exception: they don't end statements.
_fi__(_GENERIC__)
+@cindex newline, required at file end
+@cindex EOF, newline must precede
It is an error to end any statement with end-of-file: the last
character of any input file should be a newline.@refill
+@cindex continuing statements
+@cindex multi-line statements
+@cindex statement on multiple lines
You may write a statement on more than one line if you put a
backslash (@kbd{\}) immediately in front of any newlines within the
statement. When @code{_AS__} reads a backslashed newline both
An empty statement is allowed, and may include whitespace. It is ignored.
+@cindex instructions and directives
+@cindex directives and instructions
@c "key symbol" is not used elsewhere in the document; seems pedantic to
@c @defn{} it in that case, as was done previously... pesch@cygnus.com,
@c 13feb91.
language.@refill
_fi__(_GENERIC__)
+@cindex @code{:} (label)
+@cindex label (@code{:})
A label is a symbol immediately followed by a colon (@code{:}).
Whitespace before a label or after a colon is permitted, but you may not
have whitespace between a label's symbol and its colon. @xref{Labels}.
@node Constants, , Statements, Syntax
@section Constants
+
+@cindex constants
A constant is a number, written so that its value is known by
inspection, without knowing any context. Like this:
@smallexample
@node Characters, Numbers, Constants, Constants
@subsection Character Constants
+
+@cindex character constants
+@cindex constants, character
There are two kinds of character constants. A @dfn{character} stands
for one character in one byte and its value may be used in
numeric expressions. String constants (properly called string
@node Strings, Chars, Characters, Characters
@subsubsection Strings
+
+@cindex string constants
+@cindex constants, string
A @dfn{string} is written between double-quotes. It may contain
double-quotes or null characters. The way to get special characters
into a string is to @dfn{escape} these characters: precede them with
(which prevents @code{_AS__} from recognizing the second @code{\} as an
escape character). The complete list of escapes follows.
+@cindex escape codes, character
+@cindex character escape codes
@table @kbd
@c @item \a
@c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
+@c
@item \b
+@cindex @code{\b} (backspace character)
+@cindex backspace (@code{\b})
Mnemonic for backspace; for ASCII this is octal code 010.
+
@c @item \e
@c Mnemonic for EOText; for ASCII this is octal code 004.
+@c
@item \f
+@cindex @code{\f} (formfeed character)
+@cindex formfeed (@code{\f})
Mnemonic for FormFeed; for ASCII this is octal code 014.
+
@item \n
+@cindex @code{\n} (newline character)
+@cindex newline (@code{\n})
Mnemonic for newline; for ASCII this is octal code 012.
+
@c @item \p
@c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
+@c
@item \r
+@cindex @code{\r} (carriage return character)
+@cindex carriage return (@code{\r})
Mnemonic for carriage-Return; for ASCII this is octal code 015.
+
@c @item \s
@c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
@c other assemblers.
+@c
@item \t
+@cindex @code{\t} (tab)
+@cindex tab (@code{\t})
Mnemonic for horizontal Tab; for ASCII this is octal code 011.
+
@c @item \v
@c Mnemonic for Vertical tab; for ASCII this is octal code 013.
@c @item \x @var{digit} @var{digit} @var{digit}
@c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
+@c
@item \ @var{digit} @var{digit} @var{digit}
+@cindex @code{\@var{ddd}} (octal character code)
+@cindex octal character code (@code{\@var{ddd}})
An octal character code. The numeric code is 3 octal digits.
For compatibility with other Unix systems, 8 and 9 are accepted as digits:
for example, @code{\008} has the value 010, and @code{\009} the value 011.
+
@item \\
+@cindex @code{\\} (@samp{\} character)
+@cindex backslash (@code{\\})
Represents one @samp{\} character.
+
@c @item \'
@c Represents one @samp{'} (accent acute) character.
@c This is needed in single character literals
@c (@xref{Characters,,Character Constants}.) to represent
@c a @samp{'}.
+@c
@item \"
+@cindex @code{\"} (doublequote character)
+@cindex doublequote (@code{\"})
Represents one @samp{"} character. Needed in strings to represent
this character, because an unescaped @samp{"} would end the string.
+
@item \ @var{anything-else}
Any other character when escaped by @kbd{\} will give a warning, but
assemble as if the @samp{\} was not present. The idea is that if
@node Chars, , Strings, Characters
@subsubsection Characters
+
+@cindex single character constant
+@cindex character, single
+@cindex constant, single character
A single character may be written as a single quote immediately
followed by that character. The same escapes apply to characters as
to strings. So if you want to write the character backslash, you
@node Numbers, , Characters, Constants
@subsection Number Constants
+
+@cindex constants, number
+@cindex number constants
@code{_AS__} distinguishes three kinds of numbers according to how they
are stored in the target machine. @emph{Integers} are numbers that
would fit into an @code{int} in the C language. @emph{Bignums} are
@node Integers, Bignums, Numbers, Numbers
@subsubsection Integers
-@c FIXME: are binary integers in vintage as?
+@cindex integers
+@cindex constants, integer
+
+@cindex binary integers
+@cindex integers, binary
A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
the binary digits @samp{01}.
+@cindex octal integers
+@cindex integers, octal
An octal integer is @samp{0} followed by zero or more of the octal
digits (@samp{01234567}).
+@cindex decimal integers
+@cindex integers, decimal
A decimal integer starts with a non-zero digit followed by zero or
more digits (@samp{0123456789}).
+@cindex hexadecimal integers
+@cindex integers, hexadecimal
A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
@node Bignums, Flonums, Integers, Numbers
@subsubsection Bignums
+
+@cindex bignums
+@cindex constants, bignum
A @dfn{bignum} has the same syntax and semantics as an integer
except that the number (or its negative) takes more than 32 bits to
represent in binary. The distinction is made because in some places
@node Flonums, , Bignums, Numbers
_fi__(_GENERIC__||!_I960__)
@subsubsection Flonums
+@cindex flonums
+@cindex floating point numbers
+@cindex constants, floating point
+
+@cindex precision, floating point
A @dfn{flonum} represents a floating point number. The translation is
-complex: a decimal floating point number from the text is converted by
+indirect: a decimal floating point number from the text is converted by
@code{_AS__} to a generic binary floating point number of more than
sufficient precision. This generic floating point number is converted
to a particular computer's floating point format (or formats) by a
@item
The digit @samp{0}.
@item
+A letter, to tell @code{_AS__} the rest of the number is a flonum.
_if__(_GENERIC__)
-A letter, to tell @code{_AS__} the rest of the number is a flonum. @kbd{e}
-is recommended. Case is not important.
+@kbd{e} is recommended. Case is not important.
@ignore
@c FIXME: verify if flonum syntax really this vague for most cases
(Any otherwise illegal letter
_if__(_GENERIC__)
On the AMD 29K and H8/300 architectures, the letter must be:
_fi__(_GENERIC__)
-One of the letters @samp{DFPRSX} (in upper or lower case), to tell
-@code{_AS__} the rest of the number is a flonum.
+One of the letters @samp{DFPRSX} (in upper or lower case).
_fi__(_A29K__||_H8__)
_if__(_I960__)
_if__(_GENERIC__)
On the Intel 960 architecture, the letter must be:
_fi__(_GENERIC__)
-One of the letters @samp{DFT} (in upper or lower case), to tell
-@code{_AS__} the rest of the number is a flonum.
+One of the letters @samp{DFT} (in upper or lower case).
_fi__(_I960__)
@item
An optional sign: either @samp{+} or @samp{-}.
@item
An optional @dfn{integer part}: zero or more decimal digits.
@item
-An optional @dfn{fraction part}: @samp{.} followed by zero
+An optional @dfn{fractional part}: @samp{.} followed by zero
or more decimal digits.
@item
An optional exponent, consisting of:
@end itemize
@end itemize
-At least one of @var{integer part} or @var{fraction part} must be
+At least one of the integer part or the fractional part must be
present. The floating point number has the usual base-10 value.
@code{_AS__} does all processing using integers. Flonums are computed
@c turned on only by the i960 config of GAS.
@node Bit Fields, , Flonums, Numbers
@subsubsection Bit Fields
+
+@cindex bit fields
+@cindex constants, bit field
You can also define numeric constants as @dfn{bit fields}.
specify two numbers separated by a colon---
@example
@node Sections, Symbols, Syntax, Top
@chapter Sections and Relocation
+@cindex sections
+@cindex relocation
@menu
* Secs Background:: Background
* _LD__ Sections:: _LD__ Sections
* _AS__ Sections:: _AS__ Internal Sections
-_if__(!_H8__)
* Sub-Sections:: Sub-Sections
-_fi__(!_H8__)
* bss:: bss Section
@end menu
@node Secs Background, _LD__ Sections, Sections, Sections
@section Background
+
Roughly, a section is a range of addresses, with no gaps; all data
``in'' those addresses is treated the same for some particular purpose.
For example there may be a ``read only'' section.
+@cindex linker, and assembler
+@cindex assembler, and linker
The linker @code{_LD__} reads many object files (partial programs) and
combines their contents to form a runnable program. When @code{_AS__}
emits an object file, the partial program is assumed to start at address
run-time addresses to sections is called @dfn{relocation}. It includes
the task of adjusting mentions of object-file addresses so they refer to
the proper run-time addresses.
+_if__(_H8__)
+For the H8/300, @code{_AS__} pads sections if needed to ensure they end
+on a word (sixteen bit) boundary.
+_fi__(_H8__)
+@cindex standard @code{_AS__} sections
An object file written by @code{_AS__} has at least three sections, any
of which may be empty. These are named @dfn{text}, @dfn{data} and
@dfn{bss} sections.
Is the reference to an address ``Program-Counter relative''?
@end itemize
+@cindex addresses, format of
+@cindex section-relative addressing
In fact, every address @code{_AS__} ever uses is expressed as
@display
(@var{section}) + (@var{offset into section})
Apart from text, data and bss sections you need to know about the
@dfn{absolute} section. When @code{_LD__} mixes partial programs,
-addresses in the absolute section remain unchanged. That is, address
+addresses in the absolute section remain unchanged. For example, address
@code{@{absolute 0@}} is ``relocated'' to run-time address 0 by @code{_LD__}.
Although two partial programs' data sections will not overlap addresses
after linking, @emph{by definition} their absolute sections will overlap.
@table @strong
_if__(_GENERIC__||_COFF__)
+@cindex named sections
+@cindex sections, named
@item named sections
_fi__(_GENERIC__||_COFF__)
_if__(_AOUT__||_BOUT__)
+@cindex text section
+@cindex data section
@item text section
@itemx data section
_fi__(_AOUT__||_BOUT__)
in the data section.
_fi__(_AOUT__||_BOUT__)
+@cindex bss section
@item bss section
This section contains zeroed bytes when your program begins running. It
is used to hold unitialized variables or common storage. The length of
bytes in the object file. The bss section was invented to eliminate
those explicit zeros from object files.
+@cindex absolute section
@item absolute section
Address 0 of this section is always ``relocated'' to runtime address 0.
This is useful if you want to refer to an address that @code{_LD__} must
not change when relocating. In this sense we speak of absolute
addresses being ``unrelocatable'': they don't change during relocation.
+@cindex undefined section
@item undefined section
This ``section'' is a catch-all for address references to objects not in
the preceding sections.
@c FIXME: ref to some other doc on obj-file formats could go here.
-
@end table
+@cindex relocation example
An idealized example of three relocatable sections follows.
_if__(_COFF__)
-The example uses the traditional names @samp{.text} and @samp{.data} for
-two named sections.
+The example uses the traditional section names @samp{.text} and @samp{.data}.
_fi__(_COFF__)
Memory addresses are on the horizontal axis.
@c FIXME make sure no page breaks inside figure!!
@tex
-{\it Partial program \#1: }
-
+\line{\it Partial program \#1: \hfil}
\line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
\line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
-{\it Partial program \#2:}
-
+\line{\it Partial program \#2: \hfil}
\line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
\line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
-{\it linked program: }
-
+\line{\it linked program: \hfil}
\line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
\line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
-{\it addresses:}
-
+\line{\it addresses: \hfil}
\line{0\dots\hfil}
@end tex
@c END TEXI2ROFF-KILL
-_if__(!_H8__)
@node _AS__ Sections, Sub-Sections, _LD__ Sections, Sections
-_fi__(!_H8__)
-_if__(_H8__)
-@node _AS__ Sections, bss, _LD__ Sections, Sections
-_fi__(_H8__)
@section _AS__ Internal Sections
+
+@cindex internal @code{_AS__} sections
+@cindex sections in messages, internal
These sections are meant only for the internal use of @code{_AS__}. They
have no meaning at run-time. You don't really need to know about these
sections for most purposes; but they can be mentioned in @code{_AS__}
@table @b
@item absent
+@cindex absent (internal section)
An expression was expected and none was found.
@item ASSEMBLER-INTERNAL-LOGIC-ERROR!
+@cindex assembler internal logic error
An internal assembler logic error has been found. This means there is a
bug in the assembler.
@item bignum/flonum
+@cindex bignum/flonum (internal section)
If a number can't be written as a C @code{int} constant (a bignum or a
flonum, but not an integer), it is recorded as belonging to this
``section''. @code{_AS__} has to remember that a flonum or a bignum
section.
@item pass1 section
+@cindex pass1 (internal section)
The expression was impossible to evaluate in the first pass. The
assembler will attempt a second pass (second reading of the source) to
evaluate the expression. Your expression mentioned an undefined symbol
@end quotation
@item difference section
+@cindex difference (internal section)
As an assist to the C compiler, expressions of the forms
@display
(@var{undefined symbol}) @minus{} (@var{expression})
@var{something} @minus{} (@var{undefined symbol})
(@var{undefined symbol}) @minus{} (@var{undefined symbol})
@end display
+
are permitted, and belong to the difference section. @code{_AS__}
re-evaluates such expressions after the source file has been read and
the symbol table built. If by that time there are no undefined symbols
@node Sub-Sections, bss, _AS__ Sections, Sections
@section Sub-Sections
+
+@cindex numbered subsections
+@cindex grouping data
+_if__(_AOUT__||_BOUT__)
Assembled bytes
_if__(_COFF__)
conventionally
_fi__(_COFF__)
-fall into two sections: text and data. Because you may have groups of
-text or data that you want to end up near to each other in the object
-file, @code{_AS__} allows you to use @dfn{subsections} of these two
-sections. Within each section, there can be numbered subsections with
+fall into two sections: text and data.
+_fi__(_AOUT__||_BOUT__)
+You may have separate groups of
+_if__(_COFF__||_GENERIC__)
+data in named sections
+_fi__(_COFF__||_GENERIC__)
+_if__((_AOUT__||_BOUT__)&&!_GENERIC__)
+text or data
+_fi__((_AOUT__||_BOUT__)&&!_GENERIC__)
+that you want to end up near to each other in the object
+file, even though they are not contiguous in the assembler source.
+@code{_AS__} allows you to use @dfn{subsections} for this purpose.
+Within each section, there can be numbered subsections with
values from 0 to 8192. Objects assembled into the same subsection will
be grouped with other objects in the same subsection when they are all
put into the object file. For example, a compiler might want to store
(Subsections may be padded a different amount on different flavors
of @code{_AS__}.)
_fi__(_GENERIC__)
+_if__(!_GENERIC__)
+_if__(_H8__)
+On the H8/300 platform, each subsection is zero-padded to a word
+boundary (two bytes).
+_fi__(_H8__)
_if__(_I960__)
@c FIXME section padding (alignment)?
@c Rich Pixley says padding here depends on target obj code format; that
@c discussed in BFD chapter of binutils (or some such).
_fi__(_I960__)
_if__(_A29K__)
-On the AMD 29K family, no particular padding is added to section sizes;
-_AS__ forces no alignment on this platform.
+On the AMD 29K family, no particular padding is added to section or
+subsection sizes; _AS__ forces no alignment on this platform.
_fi__(_A29K__)
+_fi__(!_GENERIC__)
+
Subsections appear in your object file in numeric order, lowest numbered
to highest. (All this to be compatible with other people's assemblers.)
The object file contains no representation of subsections; @code{_LD__} and
data subsections as a data section.
To specify which subsection you want subsequent statements assembled
-into, use a @samp{.text @var{expression}} or a @samp{.data
-@var{expression}} statement. @var{Expression} should be an absolute
-expression. (@xref{Expressions}.) If you just say @samp{.text}
-then @samp{.text 0} is assumed. Likewise @samp{.data} means
-@samp{.data 0}. Assembly begins in @code{text 0}.
-For instance:
+into, use a numeric argument to specify it, in a @samp{.text
+@var{expression}} or a @samp{.data @var{expression}} statement.
+_if__(_COFF__)
+_if__(_GENERIC__)
+When generating COFF output, you
+_fi__(_GENERIC__)
+_if__(!_GENERIC__)
+You
+_fi__(!_GENERIC__)
+can also use an extra subsection
+argument with arbitrary named sections: @samp{.section @var{name},
+@var{expression}}.
+_fi__(_COFF__)
+@var{Expression} should be an absolute expression.
+(@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
+is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
+begins in @code{text 0}. For instance:
@smallexample
.text 0 # The default subsection is text 0 anyway.
.ascii "This lives in the first text subsection. *"
section that statements are being assembled into is said to be the
@dfn{active} location counter.
-_if__(!_H8__)
@node bss, , Sub-Sections, Sections
-_fi__(!_H8__)
-_if__(_H8__)
-@node bss, , _AS__ Sections, Sections
-_fi__(_H8__)
@section bss Section
+
+@cindex bss section
+@cindex common variable storage
The bss section is used for local common variable storage.
You may allocate address space in the bss section, but you may
not dictate data to load into it before your program executes. When
@node Symbols, Expressions, Sections, Top
@chapter Symbols
+
+@cindex symbols
Symbols are a central concept: the programmer uses symbols to name
things, the linker uses symbols to link, and the debugger uses symbols
to debug.
@quotation
+@cindex debuggers, and symbol order
@emph{Warning:} @code{_AS__} does not place symbols in the object file in
the same order they were declared. This may break some debuggers.
@end quotation
@node Labels, Setting Symbols, Symbols, Symbols
@section Labels
+
+@cindex labels
A @dfn{label} is written as a symbol immediately followed by a colon
@samp{:}. The symbol then represents the current value of the
active location counter, and is, for example, a suitable instruction
@node Setting Symbols, Symbol Names, Labels, Symbols
@section Giving Symbols Other Values
+
+@cindex assigning values to symbols
+@cindex symbol values, assigning
A symbol can be given an arbitrary value by writing a symbol, followed
by an equals sign @samp{=}, followed by an expression
(@pxref{Expressions}). This is equivalent to using the @code{.set}
@node Symbol Names, Dot, Setting Symbols, Symbols
@section Symbol Names
+
+@cindex symbol names
+@cindex names, symbol
Symbol names begin with a letter or with one of
_if__(!_H8__)
@samp{_.$}
_fi__(!_H8__)
_if__(_H8__)
_if__(_GENERIC__)
-dollar signs (unless otherwise noted in @ref{_MACH_DEP}),
+dollar signs (unless otherwise noted in @ref{_MACH_DEP__}),
_fi__(_GENERIC__)
and underscores.
_fi__(_H8__)
@subheading Local Symbol Names
+@cindex local symbol names
+@cindex symbol names, local
+@cindex temporary symbol names
+@cindex symbol names, temporary
Local symbols help compilers and programmers use names temporarily.
There are ten local symbol names, which are re-used throughout the
program. You may refer to them using the names @samp{0} @samp{1}
@node Dot, Symbol Attributes, Symbol Names, Symbols
@section The Special Dot Symbol
+@cindex dot (symbol)
+@cindex @code{.} (symbol)
+@cindex current address
+@cindex location counter
The special symbol @samp{.} refers to the current address that
@code{_AS__} is assembling into. Thus, the expression @samp{melvin:
.long .} will cause @code{melvin} to contain its own address.
@node Symbol Attributes, , Dot, Symbols
@section Symbol Attributes
+
+@cindex symbol attributes
+@cindex attributes, symbol
Every symbol has, as well as its name, the attributes ``Value'' and
-``Type''. Depending on output format, symbols also have auxiliary attributes.
+``Type''. Depending on output format, symbols can also have auxiliary
+attributes.
_if__(_INTERNALS__)
The detailed definitions are in _0__<a.out.h>_1__.
_fi__(_INTERNALS__)
@menu
* Symbol Value:: Value
* Symbol Type:: Type
+_if__(_AOUT__||_BOUT__)
_if__(_GENERIC__||!_BOUT__)
* a.out Symbols:: Symbol Attributes: @code{a.out}
_fi__(_GENERIC__||!_BOUT__)
_if__(_BOUT__&&!_GENERIC__)
* a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
_fi__(_BOUT__&&!_GENERIC__)
+_fi__(_AOUT__||_BOUT__)
_if__(_COFF__)
* COFF Symbols:: Symbol Attributes for COFF
_fi__(_COFF__)
@node Symbol Value, Symbol Type, Symbol Attributes, Symbol Attributes
@subsection Value
+
+@cindex value of a symbol
+@cindex symbol value
The value of a symbol is (usually) 32 bits. For a symbol which labels a
location in the text, data, bss or absolute sections the value is the
number of addresses from the start of that section to the label.
bytes (addresses). The symbol refers to the first address of the
allocated storage.
+_if__(!(_AOUT__||_BOUT__))
+@node Symbol Type, COFF Symbols, Symbol Value, Symbol Attributes
+_fi__(!(_AOUT__||_BOUT__))
+_if__((_AOUT__||_BOUT__))
@node Symbol Type, a.out Symbols, Symbol Value, Symbol Attributes
+_fi__((_AOUT__||_BOUT__))
@subsection Type
+
+@cindex type of a symbol
+@cindex symbol type
The type attribute of a symbol contains relocation (section)
information, any flag settings indicating that a symbol is external, and
(optionally), other information for linkers and debuggers. The exact
format depends on the object-code output format in use.
_if__(_AOUT__||_BOUT__)
-@menu
-* Symbol Desc:: Descriptor
-* Symbol Other:: Other
-@end menu
-
_if__(_COFF__)
@node a.out Symbols, COFF Symbols, Symbol Type, Symbol Attributes
_fi__(_COFF__)
_fi__(!_COFF__)
_if__(_BOUT__&&!_GENERIC__)
@subsection Symbol Attributes: @code{a.out}, @code{b.out}
+
+@cindex @code{b.out} symbol attributes
+@cindex symbol attributes, @code{b.out}
These symbol attributes appear only when @code{_AS__} is configured for
one of the Berkeley-descended object output formats.
_fi__(_BOUT__&&!_GENERIC__)
@subsection Symbol Attributes: @code{a.out}
_fi__(_GENERIC__||!_BOUT__)
+@cindex @code{a.out} symbol attributes
+@cindex symbol attributes, @code{a.out}
+
@menu
* Symbol Desc:: Descriptor
* Symbol Other:: Other
@node Symbol Desc, Symbol Other, a.out Symbols, a.out Symbols
@subsubsection Descriptor
+
+@cindex descriptor, of @code{a.out} symbol
This is an arbitrary 16-bit value. You may establish a symbol's
descriptor value by using a @code{.desc} statement
(@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
@node Symbol Other, , Symbol Desc, a.out Symbols
@subsubsection Other
+
+@cindex other attribute, of @code{a.out} symbol
This is an arbitrary 8-bit value. It means nothing to @code{_AS__}.
_fi__(_AOUT__||_BOUT__)
_if__(_COFF__)
+_if__(!(_AOUT__||_BOUT__))
+@node COFF Symbols, , Symbol Type, Symbol Attributes
+_fi__(!(_AOUT__||_BOUT__))
+_if__(_AOUT__||_BOUT__)
@node COFF Symbols, , a.out Symbols, Symbol Attributes
+_fi__(_AOUT__||_BOUT__)
@subsection Symbol Attributes for COFF
+
+@cindex COFF symbol attributes
+@cindex symbol attributes, COFF
+
The COFF format supports a multitude of auxiliary symbol attributes;
like the primary symbol attributes, they are set between @code{.def} and
@code{.endef} directives.
@subsubsection Primary Attributes
+
+@cindex primary attributes, COFF symbols
The symbol name is set with @code{.def}; the value and type,
respectively, with @code{.val} and @code{.type}.
@subsubsection Auxiliary Attributes
+
+@cindex auxiliary attributes, COFF symbols
The @code{_AS__} directives @code{.dim}, @code{.line}, @code{.scl},
@code{.size}, and @code{.tag} can generate auxiliary symbol table
information for COFF.
@node Expressions, Pseudo Ops, Symbols, Top
@chapter Expressions
+
+@cindex expressions
+@cindex addresses
+@cindex numeric values
An @dfn{expression} specifies an address or numeric value.
Whitespace may precede and/or follow an expression.
@node Empty Exprs, Integer Exprs, Expressions, Expressions
@section Empty Expressions
+
+@cindex empty expressions
+@cindex expressions, empty
An empty expression has no value: it is just whitespace or null.
Wherever an absolute expression is required, you may omit the
expression and @code{_AS__} will assume a value of (absolute) 0. This
@node Integer Exprs, , Empty Exprs, Expressions
@section Integer Expressions
+
+@cindex integer expressions
+@cindex expressions, integer
An @dfn{integer expression} is one or more @emph{arguments} delimited
by @emph{operators}.
@node Arguments, Operators, Integer Exprs, Integer Exprs
@subsection Arguments
+@cindex expression arguments
+@cindex arguments in expressions
+@cindex operands in expressions
+@cindex arithmetic operands
@dfn{Arguments} are symbols, numbers or subexpressions. In other
contexts arguments are sometimes called ``arithmetic operands''. In
this manual, to avoid confusing them with the ``instruction operands'' of
instructions that act on exotic constants, compatible with other
assemblers.
+@cindex subexpressions
Subexpressions are a left parenthesis @samp{(} followed by an integer
expression, followed by a right parenthesis @samp{)}; or a prefix
operator followed by an argument.
@node Operators, Prefix Ops, Arguments, Integer Exprs
@subsection Operators
+
+@cindex operators, in expressions
+@cindex arithmetic functions
+@cindex functions, in expressions
@dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
operators are followed by an argument. Infix operators appear
between their arguments. Operators may be preceded and/or followed by
whitespace.
@node Prefix Ops, Infix Ops, Operators, Integer Exprs
-@subsection Prefix Operators
+@subsection Prefix Operator
+
+@cindex prefix operators
@code{_AS__} has the following @dfn{prefix operators}. They each take
one argument, which must be absolute.
@node Infix Ops, , Prefix Ops, Integer Exprs
@subsection Infix Operators
+@cindex infix operators
+@cindex operators, permitted arguments
@dfn{Infix operators} take two arguments, one on either side. Operators
have precedence, but operations with equal precedence are performed left
to right. Apart from @code{+} or @code{-}, both arguments must be
absolute, and the result is absolute.
@enumerate
+@cindex operator precedence
+@cindex precedence of operators
@item
Highest Precedence
+
@table @code
@item *
@dfn{Multiplication}.
+
@item /
@dfn{Division}. Truncation is the same as the C operator @samp{/}
+
@item %
@dfn{Remainder}.
+
@item _0__<_1__
@itemx _0__<<_1__
@dfn{Shift Left}. Same as the C operator @samp{_0__<<_1__}
+
@item _0__>_1__
@itemx _0__>>_1__
@dfn{Shift Right}. Same as the C operator @samp{_0__>>_1__}
@item
Intermediate precedence
+
@table @code
@item |
+
@dfn{Bitwise Inclusive Or}.
+
@item &
@dfn{Bitwise And}.
+
@item ^
@dfn{Bitwise Exclusive Or}.
+
@item !
@dfn{Bitwise Or Not}.
@end table
@item
Lowest Precedence
+
@table @code
@item +
+@cindex addition, permitted arguments
+@cindex plus, permitted arguments
+@cindex arguments for addition
@dfn{Addition}. If either argument is absolute, the result
has the section of the other argument.
If either argument is pass1 or undefined, the result is pass1.
Otherwise @code{+} is illegal.
+
@item -
+@cindex subtraction, permitted arguments
+@cindex minus, permitted arguments
+@cindex arguments for subtraction
@dfn{Subtraction}. If the right argument is absolute, the
result has the section of the left argument.
If either argument is pass1 the result is pass1.
@node Pseudo Ops, _MACH_DEP__, Expressions, Top
@chapter Assembler Directives
+@cindex directives, machine independent
+@cindex pseudo-ops, machine independent
+@cindex machine independent directives
All assembler directives have names that begin with a period (@samp{.}).
-The rest of the name is letters: their case does not matter.
+The rest of the name is letters, usually in lower case.
This chapter discusses directives present regardless of the target
-machine configuration for the GNU assembler; @pxref{_MACH_DEP__} for
-additional directives.
+machine configuration for the GNU assembler.
+_if__(!_H8__)
+@xref{_MACH_DEP__} for additional directives.
+_fi__(!_H8__)
@menu
* Abort:: @code{.abort}
_if__(_COFF__||_BOUT__)
* Def:: @code{.def @var{name}}
_fi__(_COFF__||_BOUT__)
+_if__(_AOUT__||_BOUT__)
* Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
+_fi__(_AOUT__||_BOUT__)
_if__(_COFF__||_BOUT__)
* Dim:: @code{.dim}
_fi__(_COFF__||_BOUT__)
* Double:: @code{.double @var{flonums}}
+* Eject:: @code{.eject}
* Else:: @code{.else}
_if__(_COFF__||_BOUT__)
* Endef:: @code{.endef}
* Include:: @code{.include "@var{file}"}
* Int:: @code{.int @var{expressions}}
* Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
+* Lflags:: @code{.lflags}
_if__(_GENERIC__||!_A29K__)
* Line:: @code{.line @var{line-number}}
_fi__(_GENERIC__||!_A29K__)
* Ln:: @code{.ln @var{line-number}}
-* List:: @code{.list} and related directives
+* List:: @code{.list}
* Long:: @code{.long @var{expressions}}
* Lsym:: @code{.lsym @var{symbol}, @var{expression}}
+* Nolist:: @code{.nolist}
* Octa:: @code{.octa @var{bignums}}
* Org:: @code{.org @var{new-lc} , @var{fill}}
+* Psize:: @code{.psize @var{lines}, @var{columns}}
* Quad:: @code{.quad @var{bignums}}
+* Sbttl:: @code{.sbttl "@var{subheading}"}
_if__(_COFF__||_BOUT__)
* Scl:: @code{.scl @var{class}}
_fi__(_COFF__||_BOUT__)
_if__(_COFF__)
-* Section:: @code{.section @var{name}}
+* Section:: @code{.section @var{name}, @var{subsection}}
_fi__(_COFF__)
* Set:: @code{.set @var{symbol}, @var{expression}}
* Short:: @code{.short @var{expressions}}
* Tag:: @code{.tag @var{structname}}
_fi__(_COFF__||_BOUT__)
* Text:: @code{.text @var{subsection}}
+* Title:: @code{.title "@var{heading}"}
_if__(_COFF__||_BOUT__)
* Type:: @code{.type @var{int}}
* Val:: @code{.val @var{addr}}
@node Abort, Align, Pseudo Ops, Pseudo Ops
_fi__(! (_BOUT__ || _COFF__) )
@section @code{.abort}
+
+@cindex @code{abort} directive
+@cindex stopping the assembly
This directive stops the assembly immediately. It is for
compatibility with other assemblers. The original idea was that the
assembly language source would be piped into the assembler. If the sender
_if__(_COFF__)
@node coff-ABORT, Align, Abort, Pseudo Ops
@section @code{.ABORT}
+
+@cindex @code{ABORT} directive
When producing COFF output, @code{_AS__} accepts this directive as a
synonym for @samp{.abort}.
_fi__(_COFF__)
_if__(!_COFF__)
@node bout-ABORT, Align, Abort, Pseudo Ops
@section @code{.ABORT}
+
+@cindex @code{ABORT} directive
_fi__(!_COFF__)
When producing @code{b.out} output, @code{_AS__} accepts this directive,
@node Align, App-File, bout-ABORT, Pseudo Ops
_fi__( _BOUT__ && (! _COFF__))
@section @code{.align @var{abs-expr} , @var{abs-expr}}
+
+@cindex padding the location counter
+@cindex advancing location counter
+@cindex location counter, advancing
+@cindex @code{align} directive
Pad the location counter (in the current subsection) to a particular
storage boundary. The first expression (which must be absolute) is the
number of low-order zero bits the location counter will have after
@node App-File, Ascii, Align, Pseudo Ops
@section @code{.app-file @var{string}}
+
+@cindex logical file name
+@cindex file name, logical
+@cindex @code{app-file} directive
@code{.app-file}
_if__(!_A29K__)
(which may also be spelled @samp{.file})
@node Ascii, Asciz, App-File, Pseudo Ops
@section @code{.ascii "@var{string}"}@dots{}
+
+@cindex @code{ascii} directive
+@cindex string literals
@code{.ascii} expects zero or more string literals (@pxref{Strings})
separated by commas. It assembles each string (with no automatic
trailing zero byte) into consecutive addresses.
@node Asciz, Byte, Ascii, Pseudo Ops
@section @code{.asciz "@var{string}"}@dots{}
+
+@cindex @code{asciz} directive
+@cindex zero-terminated strings
+@cindex null-terminated strings
@code{.asciz} is just like @code{.ascii}, but each string is followed by
a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
@node Byte, Comm, Asciz, Pseudo Ops
@section @code{.byte @var{expressions}}
+@cindex @code{byte} directive
+@cindex integers, one byte
@code{.byte} expects zero or more expressions, separated by commas.
Each expression is assembled into the next byte.
@node Comm, Data, Byte, Pseudo Ops
@section @code{.comm @var{symbol} , @var{length} }
+
+@cindex @code{comm} directive
+@cindex symbol, common
@code{.comm} declares a named common area in the bss section. Normally
@code{_LD__} reserves memory addresses for it during linking, so no partial
program defines the location of the symbol. Use @code{.comm} to tell
@node Data, Double, Comm, Pseudo Ops
_fi__(! (_COFF__ || _BOUT__ || _AOUT__) )
@section @code{.data @var{subsection}}
+
+@cindex @code{data} directive
@code{.data} tells @code{_AS__} to assemble the following statements onto the
end of the data subsection numbered @var{subsection} (which is an
absolute expression). If @var{subsection} is omitted, it defaults
@node Def, Dim, Data, Pseudo Ops
_fi__(!(_AOUT__ || _BOUT__))
@section @code{.def @var{name}}
+
+@cindex @code{def} directive
+@cindex COFF symbols, debugging
+@cindex debugging COFF symbols
Begin defining debugging information for a symbol @var{name}; the
definition extends until the @code{.endef} directive is encountered.
_if__(_BOUT__)
@node Desc, Double, Data, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.desc @var{symbol}, @var{abs-expression}}
+
+@cindex @code{desc} directive
+@cindex COFF symbol descriptor
+@cindex symbol descriptor, COFF
This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
to the low 16 bits of an absolute expression.
@node Dim, Double, Def, Pseudo Ops
_fi__(!(_AOUT__ || _BOUT__))
@section @code{.dim}
+
+@cindex @code{dim} directive
+@cindex COFF auxiliary symbol information
+@cindex auxiliary symbol information, COFF
This directive is generated by compilers to include auxiliary debugging
information in the symbol table. It is only permitted inside
@code{.def}/@code{.endef} pairs.
_fi__(_COFF__ || _BOUT__)
_if__(_COFF__||_BOUT__)
-@node Double, Else, Dim, Pseudo Ops
+@node Double, Eject, Dim, Pseudo Ops
_fi__(_COFF__||_BOUT__)
_if__(!(_COFF__||_BOUT__))
-@node Double, Else, Desc, Pseudo Ops
+@node Double, Eject, Desc, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.double @var{flonums}}
+
+@cindex @code{double} directive
+@cindex floating point numbers (double)
@code{.double} expects zero or more flonums, separated by commas. It
assembles floating point numbers.
_if__(_GENERIC__)
_fi__(_GENERIC__)
_if__((!_GENERIC__) && _IEEEFLOAT__)
On the _HOST__ family @samp{.double} emits 64-bit floating-point numbers
-in IEEE format.
+in @sc{ieee} format.
_fi__((!_GENERIC__) && _IEEEFLOAT__)
+@node Eject, Else, Double, Pseudo Ops
+@section @code{.eject}
+
+@cindex @code{eject} directive
+@cindex new page, in listings
+@cindex page, in listings
+@cindex listing control: new page
+Force a page break at this point, when generating assembly listings.
+
_if__(_COFF__||_BOUT__)
-@node Else, Endef, Double, Pseudo Ops
+@node Else, Endef, Eject, Pseudo Ops
_fi__(_COFF__||_BOUT__)
_if__(!(_COFF__||_BOUT__))
-@node Else, Endif, Double, Pseudo Ops
+@node Else, Endif, Eject, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.else}
+
+@cindex @code{else} directive
@code{.else} is part of the @code{_AS__} support for conditional
assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
of code to be assembled if the condition for the preceding @code{.if}
_if__(0)
@node End, Endef, Else, Pseudo Ops
@section @code{.end}
+
+@cindex @code{end} directive
This doesn't do anything---but isn't an s_ignore, so I suspect it's
meant to do something eventually (which is why it isn't documented here
as "for compatibility with blah").
_if__(_COFF__||_BOUT__)
@node Endef, Endif, Else, Pseudo Ops
@section @code{.endef}
+
+@cindex @code{endef} directive
This directive flags the end of a symbol definition begun with
@code{.def}.
_if__(_BOUT__)
@node Endif, Equ, Else, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.endif}
+
+@cindex @code{endif} directive
@code{.endif} is part of the @code{_AS__} support for conditional assembly;
it marks the end of a block of code that is only assembled
conditionally. @xref{If,,@code{.if}}.
@node Equ, Extern, Endif, Pseudo Ops
@section @code{.equ @var{symbol}, @var{expression}}
+@cindex @code{equ} directive
+@cindex assigning values to symbols
+@cindex symbols, assigning values to
This directive sets the value of @var{symbol} to @var{expression}.
It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
@node Extern, Fill, Equ, Pseudo Ops
_fi__(_A29K__&&!_GENERIC__)
@section @code{.extern}
+
+@cindex @code{extern} directive
@code{.extern} is accepted in the source program---for compatibility
with other assemblers---but it is ignored. @code{_AS__} treats
all undefined symbols as external.
_if__(_GENERIC__||!_A29K__)
@node File, Fill, Extern, Pseudo Ops
-@section @code{.app-file @var{string}}
+@section @code{.file @var{string}}
+
+@cindex @code{file} directive
+@cindex logical file name
+@cindex file name, logical
@code{.file} (which may also be spelled @samp{.app-file}) tells
@code{_AS__} that we are about to start a new logical file.
@var{string} is the new file name. In general, the filename is
@node Fill, Float, Extern, Pseudo Ops
_fi__(_A29K__&&!_GENERIC__)
@section @code{.fill @var{repeat} , @var{size} , @var{value}}
+
+@cindex @code{fill} directive
+@cindex writing patterns in memory
+@cindex patterns, writing in memory
@var{result}, @var{size} and @var{value} are absolute expressions.
This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
may be zero or more. @var{Size} may be zero or more, but if it is
@node Float, Global, Fill, Pseudo Ops
@section @code{.float @var{flonums}}
+
+@cindex floating point numbers (single)
+@cindex @code{float} directive
This directive assembles zero or more flonums, separated by commas. It
has the same effect as @code{.single}.
_if__(_GENERIC__)
_fi__(_GENERIC__)
_if__((!_GENERIC__) && _IEEEFLOAT__)
On the _HOST__ family, @code{.float} emits 32-bit floating point numbers
-in IEEE format.
+in @sc{ieee} format.
_fi__((!_GENERIC__) && _IEEEFLOAT__)
@node Global, hword, Float, Pseudo Ops
@section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
+
+@cindex @code{global} directive
+@cindex symbol, making visible to linker
@code{.global} makes the symbol visible to @code{_LD__}. If you define
@var{symbol} in your partial program, its value is made available to
other partial programs that are linked with it. Otherwise,
@var{symbol} will take its attributes from a symbol of the same name
from another partial program it is linked with.
-_if__(!_I960__)
-@c FIXME BFD implications; this is different in COFF.
-This is done by setting the @code{N_EXT} bit of that symbol's type byte
-to 1. @xref{Symbol Attributes}.
-_fi__(!_I960__)
-
Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
compatibility with other assemblers.
@node hword, If, Global, Pseudo Ops
_fi__(!(_AOUT__||_BOUT__||_COFF__))
@section @code{.hword @var{expressions}}
+
+@cindex @code{hword} directive
+@cindex integers, 16-bit
+@cindex numbers, 16-bit
+@cindex sixteen bit integers
This expects zero or more @var{expressions}, and emits
a 16 bit number for each.
_if__(_AOUT__||_BOUT__||_COFF__)
@node Ident, If, hword, Pseudo Ops
@section @code{.ident}
+
+@cindex @code{ident} directive
This directive is used by some assemblers to place tags in object files.
@code{_AS__} simply accepts the directive for source-file
compatibility with such assemblers, but does not actually emit anything
@node If, Include, hword, Pseudo Ops
_fi__(!(_AOUT__||_BOUT__||_COFF__))
@section @code{.if @var{absolute expression}}
+
+@cindex conditional assembly
+@cindex @code{if} directive
@code{.if} marks the beginning of a section of code which is only
considered part of the source program being assembled if the argument
(which must be an @var{absolute expression}) is non-zero. The end of
The following variants of @code{.if} are also supported:
@table @code
-@item ifdef @var{symbol}
+@item .ifdef @var{symbol}
+@cindex @code{ifdef} directive
Assembles the following section of code if the specified @var{symbol}
has been defined.
_if__(0)
-@item ifeqs
+@item .ifeqs
+@cindex @code{ifeqs} directive
Not yet implemented.
_fi__(0)
-@item ifndef @var{symbol}
+@item .ifndef @var{symbol}
@itemx ifnotdef @var{symbol}
+@cindex @code{ifndef} directive
+@cindex @code{ifnotdef} directive
Assembles the following section of code if the specified @var{symbol}
has not been defined. Both spelling variants are equivalent.
@node Include, Int, If, Pseudo Ops
@section @code{.include "@var{file}"}
+
+@cindex @code{include} directive
+@cindex supporting files, including
+@cindex files, including
This directive provides a way to include supporting files at specified
points in your source program. The code from @var{file} is assembled as
if it followed the point of the @code{.include}; when the end of the
@node Int, Lcomm, Include, Pseudo Ops
@section @code{.int @var{expressions}}
+
+@cindex @code{int} directive
+_if__(_GENERIC__||!_H8__)
+@cindex integers, 32-bit
+_fi__(_GENERIC__||!_H8__)
Expect zero or more @var{expressions}, of any section, separated by
commas. For each expression, emit a
-_if__(!_H8__)
+_if__(_GENERIC__||!_H8__)
32-bit
-_fi__(!_H8__)
-_if__(_H8__)
+_fi__(_GENERIC__||!_H8__)
+_if__(_H8__&&!_GENERIC__)
16-bit
-_fi__(_H8__)
+_fi__(_H8__&&!_GENERIC__)
number that will, at run
time, be the value of that expression. The byte order of the
expression depends on what kind of computer will run the program.
-_if__(_GENERIC__||(!_A29K__))
-@node Lcomm, Line, Int, Pseudo Ops
-_fi__(_GENERIC__||(!_A29K__))
-_if__((!_GENERIC__)&& _A29K__)
-@node Lcomm, Ln, Int, Pseudo Ops
-_fi__((!_GENERIC__)&& _A29K__)
+@node Lcomm, Lflags, Int, Pseudo Ops
@section @code{.lcomm @var{symbol} , @var{length}}
+
+@cindex @code{lcomm} directive
+@cindex local common symbols
+@cindex symbols, local common
Reserve @var{length} (an absolute expression) bytes for a local common
denoted by @var{symbol}. The section and value of @var{symbol} are
those of the new local common. The addresses are allocated in the bss
is not declared global (@pxref{Global,,@code{.global}}), so is normally
not visible to @code{_LD__}.
+_if__(_GENERIC__||(!_A29K__))
+@node Lflags, Line, Lcomm, Pseudo Ops
+_fi__(_GENERIC__||(!_A29K__))
+_if__((!_GENERIC__)&& _A29K__)
+@node Lflags, Ln, Lcomm, Pseudo Ops
+_fi__((!_GENERIC__)&& _A29K__)
+@section @code{.lflags}
+
+@cindex @code{lflags} directive (ignored)
+@code{_AS__} accepts this directive, for compatibility with other
+assemblers, but ignores it.
+
_if__(_GENERIC__ || !_A29K__)
-@node Line, Ln, Lcomm, Pseudo Ops
+@node Line, Ln, Lflags, Pseudo Ops
@section @code{.line @var{line-number}}
+
+@cindex @code{line} directive
_fi__(_GENERIC__ || (!_A29K__))
_if__(_A29K__ && (!_GENERIC__))
-@node Ln, List, Lcomm, Pseudo Ops
+@node Ln, List, Lflags, Pseudo Ops
@section @code{.ln @var{line-number}}
+
+@cindex @code{ln} directive
_fi__(_A29K__ && (!_GENERIC__))
+@cindex logical line number
_if__(_AOUT__||_BOUT__)
Tell @code{_AS__} to change the logical line number. @var{line-number} must be
an absolute expression. The next line will have that logical line
_if__(_AOUT__&&(_GENERIC__||!_A29K__))
@node Ln, List, Line, Pseudo Ops
@section @code{.ln @var{line-number}}
+
+@cindex @code{ln} directive
@samp{.ln} is a synonym for @samp{.line}.
_fi__(_AOUT__&&(_GENERIC__||!_A29K__))
_if__(_COFF__&&!_AOUT__)
@node Ln, List, Line, Pseudo Ops
@section @code{.ln @var{line-number}}
+
+@cindex @code{ln} directive
Tell @code{_AS__} to change the logical line number. @var{line-number}
must be an absolute expression. The next line will have that logical
line number, so any other statements on the current line (after a
_fi__(_COFF__&&!_AOUT__)
@node List, Long, Ln, Pseudo Ops
-@section @code{.list} and related directives
-@code{_AS__} ignores the directives @code{.list}, @code{.nolist},
-@code{.eject}, @code{.lflags}, @code{.title}, @code{.sbttl}; however,
-they're accepted for compatibility with assemblers that use them.
+@section @code{.list}
+
+@cindex @code{list} directive
+@cindex listing control, turning on
+Control (in conjunction with the @code{.nolist} directive) whether or
+not assembly listings are generated. These two directives maintain an
+internal counter (which is zero initially). @code{.list} increments the
+counter, and @code{.nolist} decrements it. Assembly listings are
+generated whenever the counter is greater than zero.
+
+By default, listings are disabled. When you enable them (with the
+@samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
+the initial value of the listing counter is one.
@node Long, Lsym, List, Pseudo Ops
@section @code{.long @var{expressions}}
+
+@cindex @code{long} directive
@code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
-@node Lsym, Octa, Long, Pseudo Ops
+@node Lsym, Nolist, Long, Pseudo Ops
@section @code{.lsym @var{symbol}, @var{expression}}
+
+@cindex @code{lsym} directive
+@cindex symbol, not referenced in assembly
@code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
the hash table, ensuring it cannot be referenced by name during the
rest of the assembly. This sets the attributes of the symbol to be
@noindent
The new symbol is not flagged as external.
-@c FIXME: double size emitted for "octa" on i960, others? Or warn?
-@node Octa, Org, Lsym, Pseudo Ops
+@node Nolist, Octa, Lsym, Pseudo Ops
+@section @code{.nolist}
+
+@cindex @code{nolist} directive
+@cindex listing control, turning off
+Control (in conjunction with the @code{.list} directive) whether or
+not assembly listings are generated. These two directives maintain an
+internal counter (which is zero initially). @code{.list} increments the
+counter, and @code{.nolist} decrements it. Assembly listings are
+generated whenever the counter is greater than zero.
+
+@node Octa, Org, Nolist, Pseudo Ops
@section @code{.octa @var{bignums}}
+
+@c FIXME: double size emitted for "octa" on i960, others? Or warn?
+@cindex @code{octa} directive
+@cindex integer, 16-byte
+@cindex sixteen byte integer
This directive expects zero or more bignums, separated by commas. For each
bignum, it emits a 16-byte integer.
The term ``octa'' comes from contexts in which a ``word'' is two bytes;
hence @emph{octa}-word for 16 bytes.
-@node Org, Quad, Octa, Pseudo Ops
+@node Org, Psize, Octa, Pseudo Ops
@section @code{.org @var{new-lc} , @var{fill}}
+@cindex @code{org} directive
+@cindex location counter, advancing
+@cindex advancing location counter
+@cindex current address, advancing
@code{.org} will advance the location counter of the current section to
@var{new-lc}. @var{new-lc} is either an absolute expression or an
expression with the same section as the current subsection. That is,
absolute expression. If the comma and @var{fill} are omitted,
@var{fill} defaults to zero.
-_if__(_COFF__||_BOUT__)
-@node Quad, Scl, Org, Pseudo Ops
-_fi__(_COFF__||_BOUT__)
-_if__(!(_COFF__||_BOUT__))
-@node Quad, Set, Org, Pseudo Ops
-_fi__(!(_COFF__||_BOUT__))
+@node Psize, Quad, Org, Pseudo Ops
+@section @code{.psize @var{lines} , @var{columns}}
+
+@cindex @code{psize} directive
+@cindex listing control: paper size
+@cindex paper size, for listings
+Use this directive to declare the number of lines---and, optionally, the
+number of columns---to use for each page, when generating listings.
+
+If you don't use @code{.psize}, listings will use a default line-count
+of 60. You may omit the comma and @var{columns} specification; the
+default width is 200 columns.
+
+@code{_AS__} will generate formfeeds whenever the specified number of
+lines is exceeded (or whenever you explicitly request one, using
+@code{.eject}).
+
+If you specify @var{lines} as @code{0}, no formfeeds are generated save
+those explicitly specified with @code{.eject}.
+
+@node Quad, Sbttl, Psize, Pseudo Ops
@section @code{.quad @var{bignums}}
+
+@cindex @code{quad} directive
@code{.quad} expects zero or more bignums, separated by commas. For
each bignum, it emits
_if__(_GENERIC__||(!_I960__))
an 8-byte integer. If the bignum won't fit in 8
bytes, it prints a warning message; and just takes the lowest order 8
bytes of the bignum.@refill
+@cindex eight-byte integer
+@cindex integer, 8-byte
The term ``quad'' comes from contexts in which a ``word'' is two bytes;
hence @emph{quad}-word for 8 bytes.
a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
warning message; and just takes the lowest order 16 bytes of the
bignum.@refill
+@cindex sixteen-byte integer
+@cindex integer, 16-byte
_fi__(_I960__&&(!_GENERIC__))
+_if__(_COFF__||_BOUT__)
+@node Sbttl, Scl, Quad, Pseudo Ops
+_fi__(_COFF__||_BOUT__)
+_if__(!(_COFF__||_BOUT__))
+@node Sbttl, Set, Quad, Pseudo Ops
+_fi__(!(_COFF__||_BOUT__))
+@section @code{.sbttl "@var{subheading}"}
+
+@cindex @code{sbttl} directive
+@cindex subtitles for listings
+@cindex listing control: subtitle
+Use @var{subheading} as the title (third line, immediately after the
+title line) when generating assembly listings.
+
+This directive affects subsequent pages, as well as the current page if
+it appears within ten lines of the top of a page.
+
_if__(_COFF__||_BOUT__)
_if__(!_COFF__)
-@node Scl, Set, Quad, Pseudo Ops
+@node Scl, Set, Sbttl, Pseudo Ops
_fi__(!_COFF__)
_if__(_COFF__)
-@node Scl, Section, Quad, Pseudo Ops
+@node Scl, Section, Sbttl, Pseudo Ops
_fi__(_COFF__)
@section @code{.scl @var{class}}
+
+@cindex @code{scl} directive
+@cindex symbol storage class (COFF)
+@cindex COFF symbol storage class
Set the storage-class value for a symbol. This directive may only be
used inside a @code{.def}/@code{.endef} pair. Storage class may flag
whether a symbol is static or external, or it may record further
_if__(_COFF__)
@node Section, Set, Scl, Pseudo Ops
-@section @code{.section} @var{name}
-Assemble the following code into the COFF section @var{name}.
+@section @code{.section @var{name}, @var{subsection}}
+
+@cindex @code{section} directive
+@cindex named section (COFF)
+@cindex COFF named section
+Assemble the following code into end of subsection numbered
+@var{subsection} in the COFF named section @var{name}. If you omit
+@var{subsection}, @code{_AS__} uses subsection number zero.
@samp{.section .text} is equivalent to the @code{.text} directive;
@samp{.section .data} is equivalent to the @code{.data} directive.
_fi__(!(_COFF__||_BOUT__))
@section @code{.set @var{symbol}, @var{expression}}
+@cindex @code{set} directive
+@cindex symbol value, setting
This directive sets the value of @var{symbol} to @var{expression}. This
will change @var{symbol}'s value and type to conform to
@var{expression}. If @var{symbol} was flagged as external, it remains
@node Short, Single, Set, Pseudo Ops
@section @code{.short @var{expressions}}
+
+@cindex @code{short} directive
_if__(_GENERIC__ || _W16__)
@code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
_if__(_W32__)
@node Single, Space, Short, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.single @var{flonums}}
+
+@cindex @code{single} directive
+@cindex floating point numbers (single)
This directive assembles zero or more flonums, separated by commas. It
has the same effect as @code{.float}.
_if__(_GENERIC__)
_fi__(_GENERIC__)
_if__((!_GENERIC__) && _IEEEFLOAT__)
On the _HOST__ family, @code{.single} emits 32-bit floating point
-numbers in IEEE format.
+numbers in @sc{ieee} format.
_fi__((!_GENERIC__) && _IEEEFLOAT__)
_if__(_COFF__||_BOUT__)
@node Size, Space, Single, Pseudo Ops
@section @code{.size}
+
+@cindex @code{size} directive
This directive is generated by compilers to include auxiliary debugging
information in the symbol table. It is only permitted inside
@code{.def}/@code{.endef} pairs.
_fi__(!_H8__)
_if__(_GENERIC__ || !_A29K__)
@section @code{.space @var{size} , @var{fill}}
+
+@cindex @code{space} directive
+@cindex filling memory
This directive emits @var{size} bytes, each of value @var{fill}. Both
@var{size} and @var{fill} are absolute expressions. If the comma
and @var{fill} are omitted, @var{fill} is assumed to be zero.
_if__(_A29K__)
@section @code{.space}
+
+@cindex @code{space} directive
On the AMD 29K, this directive is ignored; it is accepted for
compatibility with other AMD 29K assemblers.
@node Stab, Text, Space, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.stabd, .stabn, .stabs}
+
+@cindex symbolic debuggers, information for
+@cindex @code{stab@var{x}} directives
There are three directives that begin @samp{.stab}.
All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
The symbols are not entered in the @code{_AS__} hash table: they
compatible with earlier assemblers!
@table @code
+@cindex @code{stabd} directive
@item .stabd @var{type} , @var{other} , @var{desc}
The ``name'' of the symbol generated is not even an empty string.
assembled.
@item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
-
+@cindex @code{stabn} directive
The name of the symbol is set to the empty string @code{""}.
@item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
-
+@cindex @code{stabs} directive
All five fields are specified.
@end table
_fi__(_AOUT__||_BOUT__||_COFF__)
@node Tag, Text, Space, Pseudo Ops
_fi__(_H8__)
@section @code{.tag @var{structname}}
+
+@cindex COFF structure debugging
+@cindex structure debugging, COFF
+@cindex @code{tag} directive
This directive is generated by compilers to include auxiliary debugging
information in the symbol table. It is only permitted inside
@code{.def}/@code{.endef} pairs. Tags are used to link structure
_fi__(_COFF__||_BOUT__)
_if__(_COFF__||_BOUT__)
-@node Text, Type, Tag, Pseudo Ops
+@node Text, Title, Tag, Pseudo Ops
_fi__(_COFF__||_BOUT__)
_if__(!(_COFF__||_BOUT__))
-@node Text, Word, Stab, Pseudo Ops
+@node Text, Title, Stab, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.text @var{subsection}}
+
+@cindex @code{text} directive
Tells @code{_AS__} to assemble the following statements onto the end of
the text subsection numbered @var{subsection}, which is an absolute
expression. If @var{subsection} is omitted, subsection number zero
is used.
_if__(_COFF__||_BOUT__)
-@node Type, Val, Text, Pseudo Ops
+@node Title, Type, Text, Pseudo Ops
+_fi__(_COFF__||_BOUT__)
+_if__(!(_COFF__||_BOUT__))
+@node Title, Word, Text, Pseudo Ops
+_fi__(!(_COFF__||_BOUT__))
+@section @code{.title "@var{heading}"}
+
+@cindex @code{title} directive
+@cindex listing control: title line
+Use @var{heading} as the title (second line, immediately after the
+source file name and pagenumber) when generating assembly listings.
+
+This directive affects subsequent pages, as well as the current page if
+it appears within ten lines of the top of a page.
+
+_if__(_COFF__||_BOUT__)
+@node Type, Val, Title, Pseudo Ops
@section @code{.type @var{int}}
+
+@cindex COFF symbol type
+@cindex symbol type, COFF
+@cindex @code{type} directive
This directive, permitted only within @code{.def}/@code{.endef} pairs,
records the integer @var{int} as the type attribute of a symbol table entry.
_if__(_BOUT__)
_if__(_COFF__||_BOUT__)
@node Val, Word, Type, Pseudo Ops
@section @code{.val @var{addr}}
+
+@cindex @code{val} directive
+@cindex COFF value attribute
+@cindex value attribute, COFF
This directive, permitted only within @code{.def}/@code{.endef} pairs,
records the address @var{addr} as the value attribute of a symbol table
entry.
@node Word, Deprecated, Text, Pseudo Ops
_fi__(!(_COFF__||_BOUT__))
@section @code{.word @var{expressions}}
+
+@cindex @code{word} directive
This directive expects zero or more @var{expressions}, of any section,
separated by commas.
_if__((!_GENERIC__) && _W32__)
@c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
@c happen---32-bit addressability, period; no long/short jumps.
_if__(_GENERIC__ || _DIFFTABKLUG__)
+@cindex difference tables altered
+@cindex altered difference tables
@quotation
@emph{Warning: Special Treatment to support Compilers}
@end quotation
@node Deprecated, , Word, Pseudo Ops
@section Deprecated Directives
+
+@cindex deprecated directives
+@cindex obsolescent directives
One day these directives won't work.
They are included for compatibility with older assemblers.
@table @t
@node _MACH_DEP__, Copying, Pseudo Ops, Top
_if__(_GENERIC__)
@chapter Machine Dependent Features
+
+@cindex machine dependencies
+The machine instruction sets are (almost by definition) different on
+each machine where @code{_AS__} runs. Floating point representations
+vary as well, and @code{_AS__} often supports a few additional
+directives or command-line options for compatibility with other
+assemblers on a particular platform. Finally, some versions of
+@code{_AS__} support special pseudo-instructions for branch
+optimization.
+
+This chapter discusses most of these differences, though it does not
+include details on any machine's instruction set. For details on that
+subject, see the hardware manufacturer's manual.
+
@menu
_if__(_VAX__)
* Vax-Dependent:: VAX Dependent Features
* AMD29K-Dependent:: AMD 29K Dependent Features
_fi__(_A29K__)
_if__(_H8__)
-* H8-300-Dependent:: AMD 29K Dependent Features
+* H8/300-Dependent:: AMD 29K Dependent Features
_fi__(_H8__)
_if__(_I960__)
* i960-Dependent:: Intel 80960 Dependent Features
@node Vax-Dependent, AMD29K-Dependent, Machine Dependent, Machine Dependent
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) VAX Dependent Features
+
+@cindex VAX support
@menu
* Vax-Opts:: VAX Command-Line Options
* VAX-float:: VAX Floating Point
@node Vax-Opts, VAX-float, Vax-Dependent, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) VAX Command-Line Options
+@cindex command-line options ignored, VAX
+@cindex VAX command-line options ignored
The Vax version of @code{_AS__} accepts any of the following options,
gives a warning message that the option was ignored and proceeds.
These options are for compatibility with scripts designed for other
@item @kbd{-D} (Debug)
@itemx @kbd{-S} (Symbol Table)
@itemx @kbd{-T} (Token Trace)
+@cindex @code{-D}, ignored on VAX
+@cindex @code{-S}, ignored on VAX
+@cindex @code{-T}, ignored on VAX
These are obsolete options used to debug old assemblers.
@item @kbd{-d} (Displacement size for JUMPs)
+@cindex @code{-d}, VAX option
This option expects a number following the @kbd{-d}. Like options
that expect filenames, the number may immediately follow the
@kbd{-d} (old standard) or constitute the whole of the command line
argument that follows @kbd{-d} (GNU standard).
@item @kbd{-V} (Virtualize Interpass Temporary File)
+@cindex @code{-V}, redundant on VAX
Some other assemblers use a temporary file. This option
commanded them to keep the information in active memory rather
than in a disk file. @code{_AS__} always does this, so this
option is redundant.
@item @kbd{-J} (JUMPify Longer Branches)
+@cindex @code{-J}, ignored on VAX
Many 32-bit computers permit a variety of branch instructions
to do the same job. Some of these instructions are short (and
fast) but have a limited range; others are long (and slow) but
this option to emit short and long branches.
@item @kbd{-t} (Temporary File Directory)
+@cindex @code{-t}, ignored on VAX
Some other assemblers may use a temporary file, and this option
takes a filename being the directory to site the temporary
file. @code{_AS__} does not use a temporary disk file, so this
filename.
@end table
+@cindex VMS (VAX) options
+@cindex options for VAX/VMS
+@cindex VAX/VMS options
+@cindex @code{-h} option, VAX/VMS
+@cindex @code{-+} option, VAX/VMS
+@cindex Vax-11 C compatibility
+@cindex symbols with lowercase, VAX/VMS
+@c FIXME! look into "I think" below, correct if needed, delete.
The Vax version of the assembler accepts two options when
compiled for VMS. They are @kbd{-h}, and @kbd{-+}. The
@kbd{-h} option prevents @code{_AS__} from modifying the
@node VAX-float, VAX-directives, Vax-Opts, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) VAX Floating Point
+
+@cindex VAX floating point
+@cindex floating point, VAX
Conversion of flonums to floating point is correct, and
compatible with previous assemblers. Rounding is
towards zero if the remainder is exactly half the least significant bit.
are rendered correctly. Again, rounding is towards zero in the
boundary case.
+@cindex @code{float} directive, VAX
+@cindex @code{double} directive, VAX
The @code{.float} directive produces @code{f} format numbers.
The @code{.double} directive produces @code{d} format numbers.
@node VAX-directives, VAX-opcodes, VAX-float, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) Vax Machine Directives
+
+@cindex machine directives, VAX
+@cindex VAX machine directives
The Vax version of the assembler supports four directives for
generating Vax floating point constants. They are described in the
table below.
+@cindex wide floating point directives, VAX
@table @code
@item .dfloat
+@cindex @code{dfloat} directive, VAX
This expects zero or more flonums, separated by commas, and
assembles Vax @code{d} format 64-bit floating point constants.
@item .ffloat
+@cindex @code{ffloat} directive, VAX
This expects zero or more flonums, separated by commas, and
assembles Vax @code{f} format 32-bit floating point constants.
@item .gfloat
+@cindex @code{gfloat} directive, VAX
This expects zero or more flonums, separated by commas, and
assembles Vax @code{g} format 64-bit floating point constants.
@item .hfloat
+@cindex @code{hfloat} directive, VAX
This expects zero or more flonums, separated by commas, and
assembles Vax @code{h} format 128-bit floating point constants.
@node VAX-opcodes, VAX-branch, VAX-directives, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) VAX Opcodes
+
+@cindex VAX opcode mnemonics
+@cindex opcode mnemonics, VAX
+@cindex mnemonics for opcodes, VAX
All DEC mnemonics are supported. Beware that @code{case@dots{}}
instructions have exactly 3 operands. The dispatch table that
follows the @code{case@dots{}} instruction should be made with
@node VAX-branch, VAX-operands, VAX-opcodes, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) VAX Branch Improvement
+
+@cindex VAX branch improvement
+@cindex branch improvement, VAX
+@cindex pseudo-ops for branch, VAX
Certain pseudo opcodes are permitted. They are for branch
instructions. They expand to the shortest branch instruction that
will reach the target. Generally these mnemonics are made by
@node VAX-operands, VAX-no, VAX-branch, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) VAX Operands
+
+@cindex VAX operand notation
+@cindex operand notation, VAX
+@cindex immediate character, VAX
+@cindex VAX immediate character
The immediate character is @samp{$} for Unix compatibility, not
@samp{#} as DEC writes it.
+@cindex indirect character, VAX
+@cindex VAX indirect character
The indirect character is @samp{*} for Unix compatibility, not
@samp{@@} as DEC writes it.
+@cindex displacement sizing character, VAX
+@cindex VAX displacement sizing character
The displacement sizing character is @samp{`} (an accent grave) for
Unix compatibility, not @samp{^} as DEC writes it. The letter
preceding @samp{`} may have either case. @samp{G} is not
understood, but all other letters (@code{b i l s w}) are understood.
+@cindex register names, VAX
+@cindex VAX register names
Register names understood are @code{r0 r1 r2 @dots{} r15 ap fp sp
pc}. Any case of letters will do.
@node VAX-no, , VAX-operands, Vax-Dependent
_CHAPSEC__(1+_GENERIC__) Not Supported on VAX
+
+@cindex VAX bitfields not supported
+@cindex bitfields, not supported on VAX
Vax bit fields can not be assembled with @code{_AS__}. Someone
can add the required code if they really need it.
_fi__(_VAX__)
_if__(_A29K__)
_if__(_GENERIC__)
-@node AMD29K-Dependent, H8-300-Dependent, Vax-Dependent, Machine Dependent
+@node AMD29K-Dependent, H8/300-Dependent, Vax-Dependent, Machine Dependent
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) AMD 29K Dependent Features
+
+@cindex AMD 29K support
+@cindex 29K support
@menu
* AMD29K Options:: Options
* AMD29K Syntax:: Syntax
@node AMD29K Options, AMD29K Syntax, AMD29K-Dependent, AMD29K-Dependent
_CHAPSEC__(1+_GENERIC__) Options
+@cindex AMD 29K options (none)
+@cindex options for AMD29K (none)
@code{_AS__} has no additional command-line options for the AMD
29K family.
@node AMD29K-Chars, AMD29K-Regs, AMD29K Syntax, AMD29K Syntax
_CHAPSEC__(2+_GENERIC__) Special Characters
+
+@cindex line comment character, AMD 29K
+@cindex AMD 29K line comment character
@samp{;} is the line comment character.
+@cindex line separator, AMD 29K
+@cindex AMD 29K line separator
+@cindex statement separator, AMD 29K
+@cindex AMD 29K statement separator
@samp{@@} can be used instead of a newline to separate statements.
+@cindex identifiers, AMD 29K
+@cindex AMD 29K identifiers
The character @samp{?} is permitted in identifiers (but may not begin
an identifier).
@node AMD29K-Regs, , AMD29K-Chars, AMD29K Syntax
_CHAPSEC__(2+_GENERIC__) Register Names
+
+@cindex AMD 29K register names
+@cindex register names, AMD 29K
General-purpose registers are represented by predefined symbols of the
form @samp{GR@var{nnn}} (for global registers) or @samp{LR@var{nnn}}
(for local registers), where @var{nnn} represents a number between
number between @code{0} and @code{255}. The range [0, 127] refers to
global registers, and the range [128, 255] to local registers.
+@cindex special purpose registers, AMD 29K
+@cindex AMD 29K special purpose registers
+@cindex protected registers, AMD 29K
+@cindex AMD 29K protected registers
In addition, @code{_AS__} understands the following protected
special-purpose register names for the AMD 29K family:
@node AMD29K Floating Point, AMD29K Directives, AMD29K Syntax, AMD29K-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
-The AMD 29K family uses IEEE floating-point numbers.
+
+@cindex floating point, AMD 29K (@sc{ieee})
+@cindex AMD 29K floating point (@sc{ieee})
+The AMD 29K family uses @sc{ieee} floating-point numbers.
@node AMD29K Directives, AMD29K Opcodes, AMD29K Floating Point, AMD29K-Dependent
_CHAPSEC__(1+_GENERIC__) AMD 29K Machine Directives
+@cindex machine directives, AMD 29K
+@cindex AMD 29K machine directives
@table @code
@item .block @var{size} , @var{fill}
+@cindex @code{block} directive, AMD 29K
This directive emits @var{size} bytes, each of value @var{fill}. Both
@var{size} and @var{fill} are absolute expressions. If the comma
and @var{fill} are omitted, @var{fill} is assumed to be zero.
@table @code
@item .cputype
+@cindex @code{cputype} directive, AMD 29K
This directive is ignored; it is accepted for compatibility with other
AMD 29K assemblers.
@item .file
+@cindex @code{file} directive, AMD 29K
This directive is ignored; it is accepted for compatibility with other
AMD 29K assemblers.
@end quotation
@item .line
+@cindex @code{line} directive, AMD 29K
This directive is ignored; it is accepted for compatibility with other
AMD 29K assemblers.
@item .reg @var{symbol}, @var{expression}
+@cindex @code{reg} directive, AMD 29K
@code{.reg} has the same effect as @code{.lsym}; @pxref{Lsym,,@code{.lsym}}.
@item .sect
+@cindex @code{sect} directive, AMD 29K
This directive is ignored; it is accepted for compatibility with other
AMD 29K assemblers.
@item .use @var{section name}
+@cindex @code{use} directive, AMD 29K
Establishes the section and subsection for the following code;
@var{section name} may be one of @code{.text}, @code{.data},
@code{.data1}, or @code{.lit}. With one of the first three @var{section
@node AMD29K Opcodes, , AMD29K Directives, AMD29K-Dependent
_CHAPSEC__(1+_GENERIC__) Opcodes
+
+@cindex AMD 29K opcodes
+@cindex opcodes for AMD 29K
@code{_AS__} implements all the standard AMD 29K opcodes. No
additional pseudo-instructions are needed on this family.
_fi__(_A29K__)
_if__(_H8__)
_if__(_GENERIC__)
-@node H8-300-Dependent, i960-Dependent, H8-300-Dependent, Machine Dependent
+@node H8/300-Dependent, i960-Dependent, AMD29K-Dependent, Machine Dependent
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) H8/300 Dependent Features
+
+@cindex H8/300 support
@menu
-* H8-300 Options:: Options
-* H8-300 Syntax:: Syntax
-* H8-300 Floating Point:: Floating Point
-* H8-300 Directives:: H8/300 Machine Directives
-* H8-300 Opcodes:: Opcodes
+* H8/300 Options:: Options
+* H8/300 Syntax:: Syntax
+* H8/300 Floating Point:: Floating Point
+* H8/300 Directives:: H8/300 Machine Directives
+* H8/300 Opcodes:: Opcodes
@end menu
-@node H8-300 Options, H8-300 Syntax, H8-300-Dependent, H8-300-Dependent
+@node H8/300 Options, H8/300 Syntax, H8/300-Dependent, H8/300-Dependent
_CHAPSEC__(1+_GENERIC__) Options
+
+@cindex H8/300 options (none)
+@cindex options, H8/300 (none)
@code{_AS__} has no additional command-line options for the Hitachi
H8/300 family.
-@node H8-300 Syntax, H8-300 Floating Point, H8-300 Options, H8-300-Dependent
+@node H8/300 Syntax, H8/300 Floating Point, H8/300 Options, H8/300-Dependent
_CHAPSEC__(1+_GENERIC__) Syntax
@menu
-* H8-300-Chars:: Special Characters
-* H8-300-Regs:: Register Names
-* H8-300-Addressing:: Addressing Modes
+* H8/300-Chars:: Special Characters
+* H8/300-Regs:: Register Names
+* H8/300-Addressing:: Addressing Modes
@end menu
-@node H8-300-Chars, H8-300-Regs, H8-300 Syntax, H8-300 Syntax
+@node H8/300-Chars, H8/300-Regs, H8/300 Syntax, H8/300 Syntax
_CHAPSEC__(2+_GENERIC__) Special Characters
+
+@cindex line comment character, H8/300
+@cindex H8/300 line comment character
@samp{;} is the line comment character.
+@cindex line separator, H8/300
+@cindex statement separator, H8/300
+@cindex H8/300 line separator
@samp{$} can be used instead of a newline to separate statements.
Therefore @emph{you may not use @samp{$} in symbol names} on the H8/300.
-@node H8-300-Regs, H8-300-Addressing, H8-300-Chars, H8-300 Syntax
+@node H8/300-Regs, H8/300-Addressing, H8/300-Chars, H8/300 Syntax
_CHAPSEC__(2+_GENERIC__) Register Names
+
+@cindex H8/300 registers
+@cindex registers, H8/300
You can use predefined symbols of the form @samp{r@var{n}h} and
@samp{r@var{n}l} to refer to the H8/300 registers as sixteen 8-bit
general-purpose registers. @var{n} is a digit from @samp{0} to
register). @code{r7} is used as the stack pointer, and can also be
called @code{sp}.
-@node H8-300-Addressing, , H8-300-Regs, H8-300 Syntax
+@node H8/300-Addressing, , H8/300-Regs, H8/300 Syntax
+_CHAPSEC__(2+_GENERIC__) Addressing Modes
+
+@cindex addressing modes, H8/300
+@cindex H8/300 addressing modes
_AS__ understands the following addressing modes for the H8/300:
@table @code
-@c FIXME! verify metavars, descriptions in H8/300 addressing table
-
@item r@var{n}
Register direct
@item @@r@var{n}
-@c MISSING METAVAR ABOVE??
Register indirect
-@item @@(@var{d}:16, r@var{n})
+@item @@(@var{d}, r@var{n})
+@itemx @@(@var{d}:16, r@var{n})
Register indirect: 16-bit displacement @var{d} from register @var{n}.
-@code{_AS__} understands this notation but does not require it; if you don't
-specify the displacement size, @code{_AS__} supplies it from context.
+(You may specify the @samp{:16} for clarity if you wish, but it is not
+required and has no effect.)
@item @@r@var{n}+
-@c MISSING METAVAR ABOVE??
Register indirect with post-increment
@item @@-r@var{n}
-@c MISSING METAVAR ABOVE??
Register indirect with pre-decrement
@item @code{@@}@var{aa}
@itemx @code{@@}@var{aa}:8
@itemx @code{@@}@var{aa}:16
-Absolute address @code{aa}. @code{_AS__} understands the @samp{:8} or
-@samp{:16} notation (specifying 8-bit or 16-bit addresses) but does not
-require it; if you don't specify the address size, @code{_AS__}
-supplies it from context.
+Absolute address @code{aa}. You may specify the @samp{:8} or @samp{:16}
+for clarity, if you wish; but @code{_AS__} neither requires this nor
+uses it---the address size required is taken from context.
@item #@var{xx}
@itemx #@var{xx}:8
@itemx #@var{xx}:16
-Immediate data @var{xx}. @code{_AS__} understands the @samp{:8} or
-@samp{:16} notation (specifying 8-bit or 16-bit data) but does not
-require it; if you don't specify the data size, @code{_AS__}
-supplies it from context.
+Immediate data @var{xx}. You may specify the @samp{:8} or @samp{:16}
+for clarity, if you wish; but @code{_AS__} neither requires this nor
+uses it---the data size required is taken from context.
@item @code{@@}@code{@@}@var{aa}
@itemx @code{@@}@code{@@}@var{aa}:8
-Memory indirect.
-
-@c FIXME are these just examples of an H8/300 addressing language?
-@c ...what about:
-@c @(d:8,Rn) 8-bit reg indirect?
-@c @(d:16, PC) 16-bit pc-rel?
-@c @#xx:8 immediate indirect?
+Memory indirect. You may specify the @samp{:8} for clarity, if you
+wish; but @code{_AS__} neither requires this nor uses it.
@end table
-@node H8-300 Floating Point, H8-300 Directives, H8-300 Syntax, H8-300-Dependent
+@node H8/300 Floating Point, H8/300 Directives, H8/300 Syntax, H8/300-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
-The H8/300 family uses IEEE floating-point numbers.
-@node H8-300 Directives, H8-300 Opcodes, H8-300 Floating Point, H8-300-Dependent
+@cindex floating point, H8/300 (@sc{ieee})
+@cindex H8/300 floating point (@sc{ieee})
+The H8/300 family uses @sc{ieee} floating-point numbers.
+
+@node H8/300 Directives, H8/300 Opcodes, H8/300 Floating Point, H8/300-Dependent
_CHAPSEC__(1+_GENERIC__) H8/300 Machine Directives
+
+@cindex H8/300 machine directives (none)
+@cindex machine directives, H8/300 (none)
+@cindex @code{word} directive, H8/300
+@cindex @code{int} directive, H8/300
@code{_AS__} has no machine-dependent directives for the H8/300.
+However, on this platform the @samp{.int} and @samp{.word} directives
+generate 16-bit numbers.
-@node H8-300 Opcodes, , H8-300 Directives, H8-300-Dependent
+@node H8/300 Opcodes, , H8/300 Directives, H8/300-Dependent
_CHAPSEC__(1+_GENERIC__) Opcodes
-@code{_AS__} implements all the standard H8/300 opcodes. No
-additional pseudo-instructions are needed on this family.
-For information on the H8/300 machine instruction set, see @cite{H8/300
-Series Programming Manual} (Hitachi ADE--602--025).
+@cindex H8/300 opcode summary
+@cindex opcode summary, H8/300
+@cindex mnemonics, H8/300
+@cindex instruction summary, H8/300
+For detailed information on the H8/300 machine instruction set, see
+@cite{H8/300 Series Programming Manual} (Hitachi ADE--602--025).
+
+@code{_AS__} implements all the standard H8/300 opcodes. No additional
+pseudo-instructions are needed on this family.
+
+The following table summarizes the opcodes and their arguments:
+@c kluge due to lack of group outside example
+@page
+@smallexample
+@group
+ Rs @r{source register}
+ Rd @r{destination register}
+ imm @r{immediate data}
+ x:3 @r{a bit (as a number between 0 and 7)}
+ d:8 @r{eight bit displacement from @code{pc}}
+ d:16 @r{sixteen bit displacement from @code{Rs}}
+
+add.b Rs,Rd biand #x:3,Rd
+add.b #imm:8,Rd biand #x:3,@@Rd
+add.w Rs,Rd biand #x:3,@@aa:8
+adds #1,Rd bild #x:3,Rd
+adds #2,Rd bild #x:3,@@Rd
+addx #imm:8,Rd bild #x:3,@@aa:8
+addx Rs,Rd bior #x:3,Rd
+and #imm:8,Rd bior #x:3,@@Rd
+and Rs,Rd bior #x:3,@@aa:8
+andc #imm:8,ccr bist #x:3,Rd
+band #x:3,Rd bist #x:3,@@Rd
+band #x:3,@@Rd bist #x:3,@@aa:8
+bra d:8 bixor #x:3,Rd
+bt d:8 bixor #x:3,@@Rd
+brn d:8 bixor #x:3,@@aa:8
+bf d:8 bld #x:3,Rd
+bhi d:8 bld #x:3,@@Rd
+bls d:8 bld #x:3,@@aa:8
+bcc d:8 bnot #x:3,Rd
+bhs d:8 bnot #x:3,@@Rd
+bcs d:8 bnot #x:3,@@aa:8
+blo d:8 bnot Rs,Rd
+bne d:8 bnot Rs,@@Rd
+beq d:8 bnot Rs,@@aa:8
+bvc d:8 bor #x:3,Rd
+bvs d:8 bor #x:3,@@Rd
+bpl d:8 bor #x:3,@@aa:8
+bmi d:8 bset #x:3,@@Rd
+bge d:8 bset #x:3,@@aa:8
+blt d:8 bset Rs,Rd
+bgt d:8 bset Rs,@@Rd
+ble d:8 bset Rs,@@aa:8
+bclr #x:3,Rd bsr d:8
+bclr #x:3,@@Rd bst #x:3,Rd
+bclr #x:3,@@aa:8 bst #x:3,@@Rd
+bclr Rs,Rd bst #x:3,@@aa:8
+bclr Rs,@@Rd btst #x:3,Rd
+@end group
+@group
+btst #x:3,@@Rd mov.w @@(d:16, Rs),Rd
+btst #x:3,@@aa:8 mov.w @@Rs+,Rd
+btst Rs,Rd mov.w @@aa:16,Rd
+btst Rs,@@Rd mov.w Rs,@@Rd
+btst Rs,@@aa:8 mov.w Rs,@@(d:16, Rd)
+bxor #x:3,Rd mov.w Rs,@@-Rd
+bxor #x:3,@@Rd mov.w Rs,@@aa:16
+bxor #x:3,@@aa:8 movfpe @@aa:16,Rd
+cmp.b #imm:8,Rd movtpe Rs,@@aa:16
+cmp.b Rs,Rd mulxu Rs,Rd
+cmp.w Rs,Rd neg Rs
+daa Rs nop
+das Rs not Rs
+dec Rs or #imm:8,Rd
+divxu Rs,Rd or Rs,Rd
+eepmov orc #imm:8,ccr
+inc Rs pop Rs
+jmp @@Rs push Rs
+jmp @@aa:16 rotl Rs
+jmp @@@@aa rotr Rs
+jsr @@Rs rotxl Rs
+jsr @@aa:16 rotxr Rs
+jsr @@@@aa:8 rte
+ldc #imm:8,ccr rts
+ldc Rs,ccr shal Rs
+mov.b Rs,Rd shar Rs
+mov.b #imm:8,Rd shll Rs
+mov.b @@Rs,Rd shlr Rs
+mov.b @@(d:16, Rs),Rd sleep
+mov.b @@Rs+,Rd stc ccr,Rd
+mov.b @@aa:16,Rd sub.b Rs,Rd
+mov.b @@aa:8,Rd sub.w Rs,Rd
+mov.b Rs,@@Rd subs #1,Rd
+mov.b Rs,@@(d:16, Rd) subs #2,Rd
+mov.b Rs,@@-Rd subx #imm:8,Rd
+mov.b Rs,@@aa:16 subx Rs,Rd
+mov.b Rs,@@aa:8 xor #imm:8,Rd
+mov.w Rs,Rd xor Rs,Rd
+mov.w #imm:16,Rd xorc #imm:8,ccr
+mov.w @@Rs,Rd
+@end group
+@end smallexample
+
+@cindex size suffixes, H8/300
+@cindex H8/300 size suffixes
+Four H8/300 instructions (@code{add}, @code{cmp}, @code{mov},
+@code{sub}) are defined with variants using the suffixes @samp{.b} and
+@samp{.w} to specify the size of a memory operand. @code{_AS__}
+supports these suffixes, but does not require them; since one of the
+operands is always a register, @code{_AS__} can deduce the correct size.
+
+For example, since @code{r0} refers to a 16-bit register,
+@example
+mov r0,@@foo
+@exdent is equivalent to
+mov.w r0,@@foo
+@end example
+
+If you use the size suffixes, @code{_AS__} will issue a warning if
+there's a mismatch between the suffix and the register size.
_fi__(_H8__)
_if__(_I960__)
_if__(_GENERIC__)
-@node i960-Dependent, M68K-Dependent, H8-300-Dependent, Machine Dependent
+@node i960-Dependent, M68K-Dependent, H8/300-Dependent, Machine Dependent
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) Intel 80960 Dependent Features
+
+@cindex i960 support
@menu
* Options-i960:: i960 Command-line Options
* Floating Point-i960:: Floating Point
@c FIXME! Add Syntax sec with discussion of bitfields here, at least so
@c long as they're not turned on for other machines than 960.
@node Options-i960, Floating Point-i960, i960-Dependent, i960-Dependent
+
_CHAPSEC__(1+_GENERIC__) i960 Command-line Options
+
+@cindex i960 options
+@cindex options, i960
@table @code
@item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
+@cindex i960 architecture options
+@cindex architecture options, i960
+@cindex @code{-A} options, i960
Select the 80960 architecture. Instructions or features not supported
by the selected architecture cause fatal errors.
that the @code{_AS__} output match a specific architecture, specify that
architecture explicitly.
-
@item -b
+@cindex @code{-b} option, i960
+@cindex branch recording, i960
+@cindex i960 branch recording
Add code to collect information about conditional branches taken, for
later optimization using branch prediction bits. (The conditional branch
instructions have branch prediction bits in the CA, CB, and CC
was @emph{not} taken; the differenc between the two counters is the
number of times the branch @emph{was} taken.
-A table of all such @code{Label}s is also generated, so that the
-external postprocessor @samp{gbr960} (supplied by Intel) can locate all
+@cindex @code{gbr960}, i960 postprocessor
+@cindex branch statistics table, i960
+A table of every such @code{Label} is also generated, so that the
+external postprocessor @code{gbr960} (supplied by Intel) can locate all
the counters. This table is always labelled @samp{__BRANCH_TABLE__};
this is a local symbol to permit collecting statistics for many separate
object files. The table is word aligned, and begins with a two-word
For further details, see the documentation of @samp{gbr960}.
@item -norelax
+@cindex @code{-norelax} option, i960
Normally, Compare-and-Branch instructions with targets that require
displacements greater than 13 bits (or that have external targets) are
replaced with the corresponding compare (or @samp{chkbit}) and branch
@node Floating Point-i960, Directives-i960, Options-i960, i960-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
-@code{_AS__} generates IEEE floating-point numbers for the directives
-@samp{.float}, @samp{.double}, @samp{extended}, and @samp{.single}.
+
+@cindex floating point, i960 (@sc{ieee})
+@cindex i960 floating point (@sc{ieee})
+@code{_AS__} generates @sc{ieee} floating-point numbers for the directives
+@samp{.float}, @samp{.double}, @samp{.extended}, and @samp{.single}.
@node Directives-i960, Opcodes for i960, Floating Point-i960, i960-Dependent
_CHAPSEC__(1+_GENERIC__) i960 Machine Directives
+@cindex machine directives, i960
+@cindex i960 machine directives
+
@table @code
+@cindex @code{bss} directive, i960
@item .bss @var{symbol}, @var{length}, @var{align}
Reserve @var{length} bytes in the bss section for a local @var{symbol},
aligned to the power of two specified by @var{align}. @var{length} and
@table @code
@item .extended @var{flonums}
+@cindex @code{extended} directive, i960
@code{.extended} expects zero or more flonums, separated by commas; for
-each flonum, @samp{.extended} emits an IEEE extended-format (80-bit)
+each flonum, @samp{.extended} emits an @sc{ieee} extended-format (80-bit)
floating-point number.
@item .leafproc @var{call-lab}, @var{bal-lab}
+@cindex @code{leafproc} directive, i960
You can use the @samp{.leafproc} directive in conjunction with the
optimized @code{callj} instruction to enable faster calls of leaf
procedures. If a procedure is known to call no other procedures, you
@code{bal} entry point.
@item .sysproc @var{name}, @var{index}
+@cindex @code{sysproc} directive, i960
The @samp{.sysproc} directive defines a name for a system procedure.
After you define it using @samp{.sysproc}, you can use @var{name} to
refer to the system procedure identified by @var{index} when calling
@node Opcodes for i960, , Directives-i960, i960-Dependent
_CHAPSEC__(1+_GENERIC__) i960 Opcodes
+
+@cindex opcodes, i960
+@cindex i960 opcodes
All Intel 960 machine instructions are supported;
@pxref{Options-i960,,i960 Command-line Options} for a discussion of
selecting the instruction subset for a particular 960
@node callj-i960, Compare-and-branch-i960, Opcodes for i960, Opcodes for i960
_CHAPSEC__(2+_GENERIC__) @code{callj}
+
+@cindex @code{callj}, i960 pseudo-opcode
+@cindex i960 @code{callj} pseudo-opcode
You can write @code{callj} to have the assembler or the linker determine
the most appropriate form of subroutine call: @samp{call},
@samp{bal}, or @samp{calls}. If the assembly source contains
@node Compare-and-branch-i960, , callj-i960, Opcodes for i960
_CHAPSEC__(2+_GENERIC__) Compare-and-Branch
+@cindex i960 compare and branch instructions
+@cindex compare and branch instructions, i960
The 960 architectures provide combined Compare-and-Branch instructions
that permit you to store the branch target in the lower 13 bits of the
instruction word itself. However, if you specify a branch target far
either issue an error, or convert your Compare-and-Branch instruction
into separate instructions to do the compare and the branch.
+@cindex compare and jump expansions, i960
+@cindex i960 compare and jump expansions
Whether @code{_AS__} gives an error or expands the instruction depends
on two choices you can make: whether you use the @samp{-norelax} option,
and whether you use a ``Compare and Branch'' instruction or a ``Compare
_if__(!_I960__)
@node M68K-Dependent, Sparc-Dependent, Machine Dependent, Machine Dependent
_fi__(!_I960__)
-_CHAPSEC__(0+_GENERIC__) M680x0 Dependent Features
_fi__(_GENERIC__)
+_CHAPSEC__(0+_GENERIC__) M680x0 Dependent Features
+
+@cindex M680x0 support
@menu
* M68K-Opts:: M680x0 Options
* M68K-Syntax:: Syntax
@node M68K-Opts, M68K-Syntax, M68K-Dependent, M68K-Dependent
_CHAPSEC__(1+_GENERIC__) M680x0 Options
+
+@cindex options, M680x0
+@cindex M680x0 options
The Motorola 680x0 version of @code{_AS__} has two machine dependent options.
One shortens undefined references from 32 to 16 bits, while the
other is used to tell @code{_AS__} what kind of machine it is
assembling for.
+@cindex @code{-l} option, M680x0
You can use the @kbd{-l} option to shorten the size of references to
undefined symbols. If the @kbd{-l} option is not given, references to
undefined symbols will be a full long (32 bits) wide. (Since @code{_AS__}
possible, and you know that the relevant symbols will be less than 17
bits away.
+@cindex @code{-m68000} and related options, M680x0
+@cindex architecture options, M680x0
+@cindex M680x0 architecture options
The 680x0 version of @code{_AS__} is most frequently used to assemble
programs for the Motorola MC68020 microprocessor. Occasionally it is
used to assemble programs for the mostly similar, but slightly different
@node M68K-Syntax, M68K-Float, M68K-Opts, M68K-Dependent
_CHAPSEC__(1+_GENERIC__) Syntax
+@cindex M680x0 syntax
+@cindex syntax, M680x0
+@cindex M680x0 size modifiers
+@cindex size modifiers, M680x0
The 680x0 version of @code{_AS__} uses syntax similar to the Sun assembler.
Size modifiers are appended directly to the end of the opcode without an
intervening period. For example, write @samp{movl} rather than
Program Counter (@samp{pc}), or the zero-address relative to the
program counter (@samp{zpc}).
+@cindex M680x0 addressing modes
+@cindex addressing modes, M680x0
The following addressing modes are understood:
@table @dfn
@item Immediate
@node M68K-Float, M68K-Directives, M68K-Syntax, M68K-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
+
+@cindex floating point, M680x0
+@cindex M680x0 floating point
+@c FIXME is this "not too well tested" crud STILL true?
The floating point code is not too well tested, and may have
subtle bugs in it.
Feel free to add the code!
The floating point formats generated by directives are these.
+
@table @code
@item .float
+@cindex @code{float} directive, M680x0
@code{Single} precision floating point constants.
+
@item .double
+@cindex @code{double} directive, M680x0
@code{Double} precision floating point constants.
@end table
@node M68K-Directives, M68K-opcodes, M68K-Float, M68K-Dependent
_CHAPSEC__(1+_GENERIC__) 680x0 Machine Directives
+
+@cindex M680x0 directives
+@cindex directives, M680x0
In order to be compatible with the Sun assembler the 680x0 assembler
understands the following directives.
+
@table @code
@item .data1
+@cindex @code{data1} directive, M680x0
This directive is identical to a @code{.data 1} directive.
+
@item .data2
+@cindex @code{data2} directive, M680x0
This directive is identical to a @code{.data 2} directive.
+
@item .even
+@cindex @code{even} directive, M680x0
This directive is identical to a @code{.align 1} directive.
@c Is this true? does it work???
+
@item .skip
+@cindex @code{skip} directive, M680x0
This directive is identical to a @code{.space} directive.
@end table
@node M68K-opcodes, , M68K-Directives, M68K-Dependent
_CHAPSEC__(1+_GENERIC__) Opcodes
+
+@cindex M680x0 opcodes
+@cindex opcodes, M680x0
+@cindex instruction set, M680x0
@c pesch@cygnus.com: I don't see any point in the following
@c paragraph. Bugs are bugs; how does saying this
@c help anyone?
@node M68K-Branch, M68K-Chars, M68K-opcodes, M68K-opcodes
_CHAPSEC__(2+_GENERIC__) Branch Improvement
+@cindex pseudo-opcodes, M680x0
+@cindex M680x0 pseudo-opcodes
+@cindex branch improvement, M680x0
+@cindex M680x0 branch improvement
Certain pseudo opcodes are permitted for branch instructions.
They expand to the shortest branch instruction that will reach the
target. Generally these mnemonics are made by substituting @samp{j} for
@node M68K-Chars, , M68K-Branch, M68K-opcodes
_CHAPSEC__(2+_GENERIC__) Special Characters
+
+@cindex special characters, M680x0
+@cindex M680x0 immediate character
+@cindex immediate character, M680x0
+@cindex M680x0 line comment character
+@cindex line comment character, M680x0
+@cindex comments, M680x0
The immediate character is @samp{#} for Sun compatibility. The
line-comment character is @samp{|}. If a @samp{#} appears at the
beginning of a line, it is treated as a comment unless it looks like
one) and the possible syntaxes should write this section.
@subsection Floating Point
-The 32x32 uses IEEE floating point numbers, but @code{_AS__} will only
+The 32x32 uses @sc{ieee} floating point numbers, but @code{_AS__} will only
create single or double precision values. I don't know if the 32x32
understands extended precision numbers.
_fi__((!_I80386__)&&(!_VAX__)&&(!_A29K__)&&(!_I960__)&&!_M680X0__)
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) SPARC Dependent Features
+
+@cindex SPARC support
@menu
* Sparc-Opts:: Options
* Sparc-Float:: Floating Point
@node Sparc-Opts, Sparc-Float, Sparc-Dependent, Sparc-Dependent
_CHAPSEC__(1+_GENERIC__) Options
+
+@cindex options for SPARC (none)
+@cindex SPARC options (none)
The Sparc has no machine dependent options.
@ignore
@node Sparc-Float, Sparc-Directives, Sparc-Opts, Sparc-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
+
+@cindex floating point, SPARC (@sc{ieee})
+@cindex SPARC floating point (@sc{ieee})
The Sparc uses @sc{ieee} floating-point numbers.
@node Sparc-Directives, , Sparc-Float, Sparc-Dependent
_CHAPSEC__(1+_GENERIC__) Sparc Machine Directives
+
+@cindex SPARC machine directives
+@cindex machine directives, SPARC
The Sparc version of @code{_AS__} supports the following additional
machine directives:
@table @code
@item .common
+@cindex @code{common} directive, SPARC
This must be followed by a symbol name, a positive number, and
@code{"bss"}. This behaves somewhat like @code{.comm}, but the
syntax is different.
-@item .global
-This is functionally identical to @code{.globl}.
-@c FIXME: is this still really SPARC specific? (vintage/devo)
-
@item .half
+@cindex @code{half} directive, SPARC
This is functionally identical to @code{.short}.
@item .proc
+@cindex @code{proc} directive, SPARC
This directive is ignored. Any text following it on the same
line is also ignored.
@item .reserve
+@cindex @code{reserve} directive, SPARC
This must be followed by a symbol name, a positive number, and
@code{"bss"}. This behaves somewhat like @code{.lcomm}, but the
syntax is different.
@item .seg
+@cindex @code{seg} directive, SPARC
This must be followed by @code{"text"}, @code{"data"}, or
@code{"data1"}. It behaves like @code{.text}, @code{.data}, or
@code{.data 1}.
@item .skip
+@cindex @code{skip} directive, SPARC
This is functionally identical to the @code{.space} directive.
@item .word
+@cindex @code{word} directive, SPARC
On the Sparc, the .word directive produces 32 bit values,
instead of the 16 bit values it produces on many other machines.
-
@end table
_fi__(_SPARC__)
_fi__(_GENERIC__)
_CHAPSEC__(0+_GENERIC__) 80386 Dependent Features
+@cindex i386 support
+@cindex i80306 support
@menu
* i386-Options:: Options
* i386-Syntax:: AT&T Syntax versus Intel Syntax
@node i386-Options, i386-Syntax, i386-Dependent, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Options
+
+@cindex options for i386 (none)
+@cindex i386 options (none)
The 80386 has no machine dependent options.
@node i386-Syntax, i386-Opcodes, i386-Options, i386-Dependent
_CHAPSEC__(1+_GENERIC__) AT&T Syntax versus Intel Syntax
+
+@cindex i386 syntax compatibility
+@cindex syntax compatibility, i386
In order to maintain compatibility with the output of @code{_GCC__},
@code{_AS__} supports AT&T System V/386 assembler syntax. This is quite
different from Intel syntax. We mention these differences because
almost all 80386 documents used only Intel syntax. Notable differences
between the two syntaxes are:
+
@itemize @bullet
@item
+@cindex immediate operands, i386
+@cindex i386 immediate operands
+@cindex register operands, i386
+@cindex i386 register operands
+@cindex jump/call operands, i386
+@cindex i386 jump/call operands
+@cindex operand delimiters, i386
AT&T immediate operands are preceded by @samp{$}; Intel immediate
operands are undelimited (Intel @samp{push 4} is AT&T @samp{pushl $4}).
AT&T register operands are preceded by @samp{%}; Intel register operands
operands are prefixed by @samp{*}; they are undelimited in Intel syntax.
@item
+@cindex i386 source, destination operands
+@cindex source, destination operands; i386
AT&T and Intel syntax use the opposite order for source and destination
operands. Intel @samp{add eax, 4} is @samp{addl $4, %eax}. The
@samp{source, dest} convention is maintained for compatibility with
previous Unix assemblers.
@item
+@cindex opcode suffixes, i386
+@cindex sizes operands, i386
+@cindex i386 size suffixes
In AT&T syntax the size of memory operands is determined from the last
character of the opcode name. Opcode suffixes of @samp{b}, @samp{w},
and @samp{l} specify byte (8-bit), word (16-bit), and long (32-bit)
ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T syntax.
@item
+@cindex return instructions, i386
+@cindex i386 jump, call, return
Immediate form long jumps and calls are
@samp{lcall/ljmp $@var{section}, $@var{offset}} in AT&T syntax; the
Intel syntax is
@samp{ret far @var{stack-adjust}}.
@item
+@cindex sections, i386
+@cindex i386 sections
The AT&T assembler does not provide support for multiple section
programs. Unix style systems expect all programs to be single sections.
@end itemize
@node i386-Opcodes, i386-Regs, i386-Syntax, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Opcode Naming
+
+@cindex i386 opcode naming
+@cindex opcode naming, i386
Opcode names are suffixed with one character modifiers which specify the
size of operands. The letters @samp{b}, @samp{w}, and @samp{l} specify
byte, word, and long operands. If no suffix is specified by an
thus, are @samp{bl} (from byte to long), @samp{bw} (from byte to word),
and @samp{wl} (from word to long).
-The Intel syntax conversion instructions
+@cindex conversion instructions, i386
+@cindex i386 conversion instructions
+The Intel-syntax conversion instructions
+
@itemize @bullet
@item
@samp{cbw} --- sign-extend byte in @samp{%al} to word in @samp{%ax},
+
@item
@samp{cwde} --- sign-extend word in @samp{%ax} to long in @samp{%eax},
+
@item
@samp{cwd} --- sign-extend word in @samp{%ax} to long in @samp{%dx:%ax},
+
@item
@samp{cdq} --- sign-extend dword in @samp{%eax} to quad in @samp{%edx:%eax},
@end itemize
+
+@noindent
are called @samp{cbtw}, @samp{cwtl}, @samp{cwtd}, and @samp{cltd} in
AT&T naming. @code{_AS__} accepts either naming for these instructions.
+@cindex jump instructions, i386
+@cindex call instructions, i386
Far call/jump instructions are @samp{lcall} and @samp{ljmp} in
AT&T syntax, but are @samp{call far} and @samp{jump far} in Intel
convention.
@node i386-Regs, i386-prefixes, i386-Opcodes, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Register Naming
+
+@cindex i386 registers
+@cindex registers, i386
Register operands are always prefixes with @samp{%}. The 80386 registers
consist of
+
@itemize @bullet
@item
the 8 32-bit registers @samp{%eax} (the accumulator), @samp{%ebx},
@node i386-prefixes, i386-Memory, i386-Regs, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Opcode Prefixes
+
+@cindex i386 opcode prefixes
+@cindex opcode prefixes, i386
+@cindex prefixes, i386
Opcode prefixes are used to modify the following opcode. They are used
to repeat string instructions, to provide section overrides, to perform
bus lock operations, and to give operand and address size (16-bit
@end smallexample
Here is a list of opcode prefixes:
+
@itemize @bullet
@item
+@cindex section override prefixes, i386
Section override prefixes @samp{cs}, @samp{ds}, @samp{ss}, @samp{es},
@samp{fs}, @samp{gs}. These are automatically added by specifying
using the @var{section}:@var{memory-operand} form for memory references.
@item
+@cindex size prefixes, i386
Operand/Address size prefixes @samp{data16} and @samp{addr16}
change 32-bit operands/addresses into 16-bit operands/addresses. Note
that 16-bit addressing modes (i.e. 8086 and 80286 addressing modes)
are not supported (yet).
@item
+@cindex bus lock prefixes, i386
+@cindex inhibiting interrupts, i386
The bus lock prefix @samp{lock} inhibits interrupts during
execution of the instruction it precedes. (This is only valid with
certain instructions; see a 80386 manual for details).
@item
+@cindex coprocessor wait, i386
The wait for coprocessor prefix @samp{wait} waits for the
coprocessor to complete the current instruction. This should never be
needed for the 80386/80387 combination.
@item
+@cindex repeat prefixes, i386
The @samp{rep}, @samp{repe}, and @samp{repne} prefixes are added
to string instructions to make them repeat @samp{%ecx} times.
@end itemize
@node i386-Memory, i386-jumps, i386-prefixes, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Memory References
+
+@cindex i386 memory references
+@cindex memory references, i386
An Intel syntax indirect memory reference of the form
+
@smallexample
@var{section}:[@var{base} + @var{index}*@var{scale} + @var{disp}]
@end smallexample
+
+@noindent
is translated into the AT&T syntax
+
@smallexample
@var{section}:@var{disp}(@var{base}, @var{index}, @var{scale})
@end smallexample
+
+@noindent
where @var{base} and @var{index} are the optional 32-bit base and
index registers, @var{disp} is the optional displacement, and
@var{scale}, taking the values 1, 2, 4, and 8, multiplies @var{index}
section register is used for a given memory operand.
Here are some examples of Intel and AT&T style memory references:
-@table @asis
+@table @asis
@item AT&T: @samp{-4(%ebp)}, Intel: @samp{[ebp - 4]}
@var{base} is @samp{%ebp}; @var{disp} is @samp{-4}. @var{section} is
missing, and the default section is used (@samp{%ss} for addressing with
@item AT&T: @samp{%gs:foo}; Intel @samp{gs:foo}
This selects the contents of the variable @samp{foo} with section
register @var{section} being @samp{%gs}.
-
@end table
Absolute (as opposed to PC relative) call and jump operands must be
@node i386-jumps, i386-Float, i386-Memory, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Handling of Jump Instructions
+
+@cindex jump optimization, i386
+@cindex i386 jump optimization
Jump instructions are always optimized to use the smallest possible
displacements. This is accomplished by using byte (8-bit) displacement
jumps whenever the target is sufficiently close. If a byte displacement
@node i386-Float, i386-Notes, i386-jumps, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Floating Point
+
+@cindex i386 floating point
+@cindex floating point, i386
All 80387 floating point types except packed BCD are supported.
(BCD support may be added without much difficulty). These data
types are 16-, 32-, and 64- bit integers, and single (32-bit),
@itemize @bullet
@item
+@cindex @code{float} directive, i386
+@cindex @code{single} directive, i386
+@cindex @code{double} directive, i386
+@cindex @code{tfloat} directive, i386
Floating point constructors are @samp{.float} or @samp{.single},
@samp{.double}, and @samp{.tfloat} for 32-, 64-, and 80-bit formats.
These correspond to opcode suffixes @samp{s}, @samp{l}, and @samp{t}.
@samp{fstpt} (store temporary real and pop stack) instructions.
@item
+@cindex @code{word} directive, i386
+@cindex @code{long} directive, i386
+@cindex @code{int} directive, i386
+@cindex @code{quad} directive, i386
Integer constructors are @samp{.word}, @samp{.long} or @samp{.int}, and
@samp{.quad} for the 16-, 32-, and 64-bit integer formats. The corresponding
opcode suffixes are @samp{s} (single), @samp{l} (long), and @samp{q}
Register to register operations do not require opcode suffixes,
so that @samp{fst %st, %st(1)} is equivalent to @samp{fstl %st, %st(1)}.
+@cindex i386 @code{fwait} instruction
+@cindex @code{fwait instruction}, i386
Since the 80387 automatically synchronizes with the 80386 @samp{fwait}
instructions are almost never needed (this is not the case for the
80286/80287 and 8086/8087 combinations). Therefore, @code{_AS__} suppresses
@node i386-Notes, , i386-Float, i386-Dependent
_CHAPSEC__(1+_GENERIC__) Notes
+
+@cindex i386 @code{mul}, @code{imul} instructions
+@cindex @code{mul} instruction, i386
+@cindex @code{imul} instruction, i386
There is some trickery concerning the @samp{mul} and @samp{imul}
instructions that deserves mention. The 16-, 32-, and 64-bit expanding
multiplies (base opcode @samp{0xf6}; extension 4 for @samp{mul} and 5
@end table
_fi__(0)
-@node Copying, , Machine Dependent, Top
+@node Copying, Index, _MACH_DEP__, Top
@unnumbered GNU GENERAL PUBLIC LICENSE
+
+@cindex license
+@cindex GPL
+@cindex copying @code{_AS__}
@center Version 2, June 1991
@display
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:
-@alphaenumerate
+@enumerate a
@item
You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.
License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
-@end alphaenumerate
+@end enumerate
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:
-@alphaenumerate
+@enumerate a
@item
Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
-@end alphaenumerate
+@end enumerate
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.
+@node Index, , Copying, Top
+@unnumbered Index
+
+@printindex cp
+
@summarycontents
@contents
@bye
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