2 @c Copyright (c) 1990 1991 1992 1993 Free Software Foundation, Inc.
3 @c This file is part of the source for the GDB manual.
4 @c This text diverted to "Remote Debugging" section in general case;
5 @c however, if we're doing a manual specifically for one of these, it
6 @c belongs up front (in "Getting In and Out" chapter).
10 @subsection The @value{GDBN} remote serial protocol
12 @cindex remote serial debugging, overview
13 To debug a program running on another machine (the debugging
14 @dfn{target} machine), you must first arrange for all the usual
15 prerequisites for the program to run by itself. For example, for a C
20 A startup routine to set up the C runtime environment; these usually
21 have a name like @file{crt0}. The startup routine may be supplied by
22 your hardware supplier, or you may have to write your own.
25 You probably need a C subroutine library to support your program's
26 subroutine calls, notably managing input and output.
29 A way of getting your program to the other machine---for example, a
30 download program. These are often supplied by the hardware
31 manufacturer, but you may have to write your own from hardware
35 The next step is to arrange for your program to use a serial port to
36 communicate with the machine where @value{GDBN} is running (the @dfn{host}
37 machine). In general terms, the scheme looks like this:
41 @value{GDBN} already understands how to use this protocol; when everything
42 else is set up, you can simply use the @samp{target remote} command
43 (@pxref{Targets,,Specifying a Debugging Target}).
46 you must link with your program a few special-purpose subroutines that
47 implement the @value{GDBN} remote serial protocol. The file containing these
48 subroutines is called a @dfn{debugging stub}.
51 On certain remote targets, you can use an auxiliary program
52 @code{gdbserver} instead of linking a stub into your program.
53 @xref{Server,,Using the @code{gdbserver} program}, for details.
57 The debugging stub is specific to the architecture of the remote
58 machine; for example, use @file{sparc-stub.c} to debug programs on
61 @cindex remote serial stub list
62 These working remote stubs are distributed with @value{GDBN}:
67 For @sc{sparc} architectures.
71 @cindex Motorola 680x0
73 For Motorola 680x0 architectures.
79 For Intel 386 and compatible architectures.
82 The @file{README} file in the @value{GDBN} distribution may list other
86 * Stub Contents:: What the stub can do for you
87 * Bootstrapping:: What you must do for the stub
88 * Debug Session:: Putting it all together
89 * Protocol:: Outline of the communication protocol
91 * Server:: Using the `gdbserver' program
96 @subsubsection What the stub can do for you
98 @cindex remote serial stub
99 The debugging stub for your architecture supplies these three
103 @item set_debug_traps
104 @kindex set_debug_traps
105 @cindex remote serial stub, initialization
106 This routine arranges for @code{handle_exception} to run when your
107 program stops. You must call this subroutine explicitly near the
108 beginning of your program.
110 @item handle_exception
111 @kindex handle_exception
112 @cindex remote serial stub, main routine
113 This is the central workhorse, but your program never calls it
114 explicitly---the setup code arranges for @code{handle_exception} to
115 run when a trap is triggered.
117 @code{handle_exception} takes control when your program stops during
118 execution (for example, on a breakpoint), and mediates communications
119 with @value{GDBN} on the host machine. This is where the communications
120 protocol is implemented; @code{handle_exception} acts as the @value{GDBN}
121 representative on the target machine; it begins by sending summary
122 information on the state of your program, then continues to execute,
123 retrieving and transmitting any information @value{GDBN} needs, until you
124 execute a @value{GDBN} command that makes your program resume; at that point,
125 @code{handle_exception} returns control to your own code on the target
129 @cindex @code{breakpoint} subroutine, remote
130 Use this auxiliary subroutine to make your program contain a
131 breakpoint. Depending on the particular situation, this may be the only
132 way for @value{GDBN} to get control. For instance, if your target
133 machine has some sort of interrupt button, you won't need to call this;
134 pressing the interrupt button will transfer control to
135 @code{handle_exception}---in effect, to @value{GDBN}. On some machines,
136 simply receiving characters on the serial port may also trigger a trap;
137 again, in that situation, you don't need to call @code{breakpoint} from
138 your own program---simply running @samp{target remote} from the host
139 @value{GDBN} session will get control.
141 Call @code{breakpoint} if none of these is true, or if you simply want
142 to make certain your program stops at a predetermined point for the
143 start of your debugging session.
147 @subsubsection What you must do for the stub
149 @cindex remote stub, support routines
150 The debugging stubs that come with @value{GDBN} are set up for a particular
151 chip architecture, but they have no information about the rest of your
152 debugging target machine. To allow the stub to work, you must supply
153 these special low-level subroutines:
156 @item int getDebugChar()
158 Write this subroutine to read a single character from the serial port.
159 It may be identical to @code{getchar} for your target system; a
160 different name is used to allow you to distinguish the two if you wish.
162 @item void putDebugChar(int)
164 Write this subroutine to write a single character to the serial port.
165 It may be identical to @code{putchar} for your target system; a
166 different name is used to allow you to distinguish the two if you wish.
168 @item void exceptionHandler (int @var{exception_number}, void *@var{exception_address})
169 @kindex exceptionHandler
170 Write this function to install @var{exception_address} in the exception
171 handling tables. You need to do this because the stub does not have any
172 way of knowing what the exception handling tables on your target system
173 are like (for example, the processor's table might be in @sc{rom},
174 containing entries which point to a table in @sc{ram}).
175 @var{exception_number} is the exception number which should be changed;
176 its meaning is architecture-dependent (for example, different numbers
177 might represent divide by zero, misaligned access, etc). When this
178 exception occurs, control should be transferred directly to
179 @var{exception_address}, and the processor state (stack, registers,
180 etc.) should be just as it is when a processor exception occurs. So if
181 you want to use a jump instruction to reach @var{exception_address}, it
182 should be a simple jump, not a jump to subroutine.
184 For the 386, @var{exception_address} should be installed as an interrupt
185 gate so that interrupts are masked while the handler runs. The gate
186 should be at privilege level 0 (the most privileged level). The
187 @sc{sparc} and 68k stubs are able to mask interrupts themself without
188 help from @code{exceptionHandler}.
190 @item void flush_i_cache()
191 @kindex flush_i_cache
192 Write this subroutine to flush the instruction cache, if any, on your
193 target machine. If there is no instruction cache, this subroutine may
196 On target machines that have instruction caches, @value{GDBN} requires this
197 function to make certain that the state of your program is stable.
201 You must also make sure this library routine is available:
204 @item void *memset(void *, int, int)
206 This is the standard library function @code{memset} that sets an area of
207 memory to a known value. If you have one of the free versions of
208 @code{libc.a}, @code{memset} can be found there; otherwise, you must
209 either obtain it from your hardware manufacturer, or write your own.
212 If you do not use the GNU C compiler, you may need other standard
213 library subroutines as well; this will vary from one stub to another,
214 but in general the stubs are likely to use any of the common library
215 subroutines which @code{gcc} generates as inline code.
219 @subsubsection Putting it all together
221 @cindex remote serial debugging summary
222 In summary, when your program is ready to debug, you must follow these
227 Make sure you have the supporting low-level routines
228 (@pxref{Bootstrapping,,What you must do for the stub}):
230 @code{getDebugChar}, @code{putDebugChar},
231 @code{flush_i_cache}, @code{memset}, @code{exceptionHandler}.
235 Insert these lines near the top of your program:
243 For the 680x0 stub only, you need to provide a variable called
244 @code{exceptionHook}. Normally you just use
247 void (*exceptionHook)() = 0;
250 but if before calling @code{set_debug_traps}, you set it to point to a
251 function in your program, that function is called when
252 @code{@value{GDBN}} continues after stopping on a trap (for example, bus
253 error). The function indicated by @code{exceptionHook} is called with
254 one parameter: an @code{int} which is the exception number.
257 Compile and link together: your program, the @value{GDBN} debugging stub for
258 your target architecture, and the supporting subroutines.
261 Make sure you have a serial connection between your target machine and
262 the @value{GDBN} host, and identify the serial port used for this on the host.
265 @c The "remote" target now provides a `load' command, so we should
266 @c document that. FIXME.
267 Download your program to your target machine (or get it there by
268 whatever means the manufacturer provides), and start it.
271 To start remote debugging, run @value{GDBN} on the host machine, and specify
272 as an executable file the program that is running in the remote machine.
273 This tells @value{GDBN} how to find your program's symbols and the contents
276 @cindex serial line, @code{target remote}
277 Then establish communication using the @code{target remote} command.
278 Its argument specifies how to communicate with the target
279 machine---either via a devicename attached to a direct serial line, or a
280 TCP port (usually to a terminal server which in turn has a serial line
281 to the target). For example, to use a serial line connected to the
282 device named @file{/dev/ttyb}:
285 target remote /dev/ttyb
288 @cindex TCP port, @code{target remote}
289 To use a TCP connection, use an argument of the form
290 @code{@var{host}:port}. For example, to connect to port 2828 on a
291 terminal server named @code{manyfarms}:
294 target remote manyfarms:2828
298 Now you can use all the usual commands to examine and change data and to
299 step and continue the remote program.
301 To resume the remote program and stop debugging it, use the @code{detach}
304 @cindex interrupting remote programs
305 @cindex remote programs, interrupting
306 Whenever @value{GDBN} is waiting for the remote program, if you type the
307 interrupt character (often @key{C-C}), @value{GDBN} attempts to stop the
308 program. This may or may not succeed, depending in part on the hardware
309 and the serial drivers the remote system uses. If you type the
310 interrupt character once again, @value{GDBN} displays this prompt:
313 Interrupted while waiting for the program.
314 Give up (and stop debugging it)? (y or n)
317 If you type @kbd{y}, @value{GDBN} abandons the remote debugging session.
318 (If you decide you want to try again later, you can use @samp{target
319 remote} again to connect once more.) If you type @kbd{n}, @value{GDBN}
320 goes back to waiting.
323 @subsubsection Outline of the communication protocol
325 @cindex debugging stub, example
326 @cindex remote stub, example
327 @cindex stub example, remote debugging
328 The stub files provided with @value{GDBN} implement the target side of the
329 communication protocol, and the @value{GDBN} side is implemented in the
330 @value{GDBN} source file @file{remote.c}. Normally, you can simply allow
331 these subroutines to communicate, and ignore the details. (If you're
332 implementing your own stub file, you can still ignore the details: start
333 with one of the existing stub files. @file{sparc-stub.c} is the best
334 organized, and therefore the easiest to read.)
336 However, there may be occasions when you need to know something about
337 the protocol---for example, if there is only one serial port to your
338 target machine, you might want your program to do something special if
339 it recognizes a packet meant for @value{GDBN}.
341 @cindex protocol, @value{GDBN} remote serial
342 @cindex serial protocol, @value{GDBN} remote
343 @cindex remote serial protocol
344 All @value{GDBN} commands and responses (other than acknowledgements, which
345 are single characters) are sent as a packet which includes a
346 checksum. A packet is introduced with the character @samp{$}, and ends
347 with the character @samp{#} followed by a two-digit checksum:
350 $@var{packet info}#@var{checksum}
353 @cindex checksum, for @value{GDBN} remote
355 @var{checksum} is computed as the modulo 256 sum of the @var{packet
358 When either the host or the target machine receives a packet, the first
359 response expected is an acknowledgement: a single character, either
360 @samp{+} (to indicate the package was received correctly) or @samp{-}
361 (to request retransmission).
363 The host (@value{GDBN}) sends commands, and the target (the debugging stub
364 incorporated in your program) sends data in response. The target also
365 sends data when your program stops.
367 Command packets are distinguished by their first character, which
368 identifies the kind of command.
370 These are the commands currently supported:
374 Requests the values of CPU registers.
377 Sets the values of CPU registers.
379 @item m@var{addr},@var{count}
380 Read @var{count} bytes at location @var{addr}.
382 @item M@var{addr},@var{count}:@dots{}
383 Write @var{count} bytes at location @var{addr}.
387 Resume execution at the current address (or at @var{addr} if supplied).
391 Step the target program for one instruction, from either the current
392 program counter or from @var{addr} if supplied.
395 Kill the target program.
398 Report the most recent signal. To allow you to take advantage of the
399 @value{GDBN} signal handling commands, one of the functions of the debugging
400 stub is to report CPU traps as the corresponding POSIX signal values.
403 @kindex set remotedebug
404 @kindex show remotedebug
405 @cindex packets, reporting on stdout
406 @cindex serial connections, debugging
407 If you have trouble with the serial connection, you can use the command
408 @code{set remotedebug}. This makes @value{GDBN} report on all packets sent
409 back and forth across the serial line to the remote machine. The
410 packet-debugging information is printed on the @value{GDBN} standard output
411 stream. @code{set remotedebug off} turns it off, and @code{show
412 remotedebug} will show you its current state.
416 @subsubsection Using the @code{gdbserver} program
419 @cindex remote connection without stubs
420 @code{gdbserver} is a control program for Unix-like systems, which
421 allows you to connect your program with a remote @value{GDBN} via
422 @code{target remote}---but without linking in the usual debugging stub.
424 @code{gdbserver} is not a complete replacement for the debugging stubs,
425 because it requires essentially the same operating-system facilities
426 that @value{GDBN} itself does. In fact, a system that can run
427 @code{gdbserver} to connect to a remote @value{GDBN} could also run
428 @var{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless,
429 because it is a much smaller program than @value{GDBN} itself. It is
430 also easier to port than all of @var{GDBN}, so you may be able to get
431 started more quickly on a new system by using @code{gdbserver}.
433 @value{GDBN} and @code{gdbserver} communicate via either a serial line
434 or a TCP connection, using the standard @value{GDBN} remote serial
439 you need to have a copy of the program you want to debug.
440 @code{gdbserver} does not need your program's symbol table, so you can
441 strip the program if necessary to save space. @value{GDBN} on the host
442 system does all the symbol handling.
444 To use the server, you must tell it how to communicate with @value{GDB};
445 the name of your program; and the arguments for your program. The
449 target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ]
452 @var{comm} is either a device name (to use a serial line) or a TCP
453 hostname and portnumber. For example, to debug emacs with the argument
454 @samp{foo.txt} and communicate with @value{GDBN} over the serial port
458 target> gdbserver /dev/com1 emacs foo.txt
461 @code{gdbserver} waits passively for the host @value{GDBN} to communicate
464 To use a TCP connection instead of a serial line:
467 target> gdbserver host:2345 emacs foo.txt
470 The only difference from the previous example is the first argument,
471 specifying that you are communicating with the host @value{GDBN} via
472 TCP. The @samp{host:2345} argument means that @code{gdbserver} is to
473 expect a TCP connection from machine @samp{host} to local TCP port 2345.
474 (Currently, the @samp{host} part is ignored.) You can choose any number
475 you want for the port number as long as it does not conflict with any
476 TCP ports already in use on the target system.@footnote{If you choose a
477 port number that conflicts with another service, @code{gdbserver} prints
478 an error message and exits.} You must use the same port number with the
479 host @value{GDBN} @code{target remote} command.
482 you need an unstripped copy of your program, since
483 @value{GDBN} needs symbols and debugging information. Start up
484 @value{GDBN} as usual, using the name of the local copy of your program
485 as the first argument. (You may also need the
486 @samp{--baud} option if the serial line is running at anything other than 9600 bps.)
487 After that, use @code{target remote} to establish communications with @code{gdbserver}. Its argument is either
488 a device name (usually a serial device, like @file{/dev/ttyb}), or a TCP
489 port descriptof in the form @code{@var{host}:@var{PORT}}. For example:
492 (@value{GDBP}) target remote /dev/ttyb
496 communicates with the server via serial line @file{/dev/ttyb}, and
499 (@value{GDBP}) target remote the-target:2345
503 communicates via a TCP connection to port 2345 on host @file{the-target}.
504 For TCP connections, you must start up @code{gdbserver} prior to using
505 the @code{target remote} command. Otherwise you may get an error whose
506 text depends on the host system, but which usually looks something like
507 @samp{Connection refused}.
514 @node i960-Nindy Remote
515 @subsection @value{GDBN} with a remote i960 (Nindy)
519 @dfn{Nindy} is a ROM Monitor program for Intel 960 target systems. When
520 @value{GDBN} is configured to control a remote Intel 960 using Nindy, you can
521 tell @value{GDBN} how to connect to the 960 in several ways:
525 Through command line options specifying serial port, version of the
526 Nindy protocol, and communications speed;
529 By responding to a prompt on startup;
532 By using the @code{target} command at any point during your @value{GDBN}
533 session. @xref{Target Commands, ,Commands for managing targets}.
538 * Nindy Startup:: Startup with Nindy
539 * Nindy Options:: Options for Nindy
540 * Nindy Reset:: Nindy reset command
544 @subsubsection Startup with Nindy
546 If you simply start @code{@value{GDBP}} without using any command-line
547 options, you are prompted for what serial port to use, @emph{before} you
548 reach the ordinary @value{GDBN} prompt:
551 Attach /dev/ttyNN -- specify NN, or "quit" to quit:
555 Respond to the prompt with whatever suffix (after @samp{/dev/tty})
556 identifies the serial port you want to use. You can, if you choose,
557 simply start up with no Nindy connection by responding to the prompt
558 with an empty line. If you do this and later wish to attach to Nindy,
559 use @code{target} (@pxref{Target Commands, ,Commands for managing targets}).
562 @subsubsection Options for Nindy
564 These are the startup options for beginning your @value{GDBN} session with a
565 Nindy-960 board attached:
569 Specify the serial port name of a serial interface to be used to connect
570 to the target system. This option is only available when @value{GDBN} is
571 configured for the Intel 960 target architecture. You may specify
572 @var{port} as any of: a full pathname (e.g. @samp{-r /dev/ttya}), a
573 device name in @file{/dev} (e.g. @samp{-r ttya}), or simply the unique
574 suffix for a specific @code{tty} (e.g. @samp{-r a}).
577 (An uppercase letter ``O'', not a zero.) Specify that @value{GDBN} should use
578 the ``old'' Nindy monitor protocol to connect to the target system.
579 This option is only available when @value{GDBN} is configured for the Intel 960
583 @emph{Warning:} if you specify @samp{-O}, but are actually trying to
584 connect to a target system that expects the newer protocol, the connection
585 fails, appearing to be a speed mismatch. @value{GDBN} repeatedly
586 attempts to reconnect at several different line speeds. You can abort
587 this process with an interrupt.
591 Specify that @value{GDBN} should first send a @code{BREAK} signal to the target
592 system, in an attempt to reset it, before connecting to a Nindy target.
595 @emph{Warning:} Many target systems do not have the hardware that this
596 requires; it only works with a few boards.
600 The standard @samp{-b} option controls the line speed used on the serial
605 @subsubsection Nindy reset command
610 For a Nindy target, this command sends a ``break'' to the remote target
611 system; this is only useful if the target has been equipped with a
612 circuit to perform a hard reset (or some other interesting action) when
620 @subsection @value{GDBN} and the UDI protocol for AMD29K
623 @cindex AMD29K via UDI
624 @value{GDBN} supports AMD's UDI (``Universal Debugger Interface'')
625 protocol for debugging the a29k processor family. To use this
626 configuration with AMD targets running the MiniMON monitor, you need the
627 program @code{MONTIP}, available from AMD at no charge. You can also
628 use @value{GDBN} with the UDI conformant a29k simulator program
629 @code{ISSTIP}, also available from AMD.
632 @item target udi @var{keyword}
634 Select the UDI interface to a remote a29k board or simulator, where
635 @var{keyword} is an entry in the AMD configuration file @file{udi_soc}.
636 This file contains keyword entries which specify parameters used to
637 connect to a29k targets. If the @file{udi_soc} file is not in your
638 working directory, you must set the environment variable @samp{UDICONF}
643 @subsection @value{GDBN} and the EBMON protocol for AMD29K
646 @cindex running 29K programs
648 AMD distributes a 29K development board meant to fit in a PC, together
649 with a DOS-hosted monitor program called @code{EBMON}. As a shorthand
650 term, this development system is called the ``EB29K''. To use
651 @value{GDBN} from a Unix system to run programs on the EB29K board, you
652 must first connect a serial cable between the PC (which hosts the EB29K
653 board) and a serial port on the Unix system. In the following, we
654 assume you've hooked the cable between the PC's @file{COM1} port and
655 @file{/dev/ttya} on the Unix system.
658 * Comms (EB29K):: Communications setup
659 * gdb-EB29K:: EB29K cross-debugging
660 * Remote Log:: Remote log
664 @subsubsection Communications setup
666 The next step is to set up the PC's port, by doing something like this
670 C:\> MODE com1:9600,n,8,1,none
674 This example---run on an MS DOS 4.0 system---sets the PC port to 9600
675 bps, no parity, eight data bits, one stop bit, and no ``retry'' action;
676 you must match the communications parameters when establishing the Unix
677 end of the connection as well.
678 @c FIXME: Who knows what this "no retry action" crud from the DOS manual may
679 @c mean? It's optional; leave it out? ---pesch@cygnus.com, 25feb91
681 To give control of the PC to the Unix side of the serial line, type
682 the following at the DOS console:
689 (Later, if you wish to return control to the DOS console, you can use
690 the command @code{CTTY con}---but you must send it over the device that
691 had control, in our example over the @file{COM1} serial line).
693 From the Unix host, use a communications program such as @code{tip} or
694 @code{cu} to communicate with the PC; for example,
697 cu -s 9600 -l /dev/ttya
701 The @code{cu} options shown specify, respectively, the linespeed and the
702 serial port to use. If you use @code{tip} instead, your command line
703 may look something like the following:
710 Your system may require a different name where we show
711 @file{/dev/ttya} as the argument to @code{tip}. The communications
712 parameters, including which port to use, are associated with the
713 @code{tip} argument in the ``remote'' descriptions file---normally the
714 system table @file{/etc/remote}.
715 @c FIXME: What if anything needs doing to match the "n,8,1,none" part of
716 @c the DOS side's comms setup? cu can support -o (odd
717 @c parity), -e (even parity)---apparently no settings for no parity or
718 @c for character size. Taken from stty maybe...? John points out tip
719 @c can set these as internal variables, eg ~s parity=none; man stty
720 @c suggests that it *might* work to stty these options with stdin or
721 @c stdout redirected... ---pesch@cygnus.com, 25feb91
724 Using the @code{tip} or @code{cu} connection, change the DOS working
725 directory to the directory containing a copy of your 29K program, then
726 start the PC program @code{EBMON} (an EB29K control program supplied
727 with your board by AMD). You should see an initial display from
728 @code{EBMON} similar to the one that follows, ending with the
729 @code{EBMON} prompt @samp{#}---
734 G:\> CD \usr\joe\work29k
736 G:\USR\JOE\WORK29K> EBMON
737 Am29000 PC Coprocessor Board Monitor, version 3.0-18
738 Copyright 1990 Advanced Micro Devices, Inc.
739 Written by Gibbons and Associates, Inc.
741 Enter '?' or 'H' for help
743 PC Coprocessor Type = EB29K
745 Memory Base = 0xd0000
747 Data Memory Size = 2048KB
748 Available I-RAM Range = 0x8000 to 0x1fffff
749 Available D-RAM Range = 0x80002000 to 0x801fffff
752 Register Stack Size = 0x800
753 Memory Stack Size = 0x1800
756 Am29027 Available = No
757 Byte Write Available = Yes
762 Then exit the @code{cu} or @code{tip} program (done in the example by
763 typing @code{~.} at the @code{EBMON} prompt). @code{EBMON} will keep
764 running, ready for @value{GDBN} to take over.
766 For this example, we've assumed what is probably the most convenient
767 way to make sure the same 29K program is on both the PC and the Unix
768 system: a PC/NFS connection that establishes ``drive @code{G:}'' on the
769 PC as a file system on the Unix host. If you do not have PC/NFS or
770 something similar connecting the two systems, you must arrange some
771 other way---perhaps floppy-disk transfer---of getting the 29K program
772 from the Unix system to the PC; @value{GDBN} will @emph{not} download it over the
776 @subsubsection EB29K cross-debugging
778 Finally, @code{cd} to the directory containing an image of your 29K
779 program on the Unix system, and start @value{GDBN}---specifying as argument the
780 name of your 29K program:
787 Now you can use the @code{target} command:
790 target amd-eb /dev/ttya 9600 MYFOO
791 @c FIXME: test above 'target amd-eb' as spelled, with caps! caps are meant to
792 @c emphasize that this is the name as seen by DOS (since I think DOS is
793 @c single-minded about case of letters). ---pesch@cygnus.com, 25feb91
797 In this example, we've assumed your program is in a file called
798 @file{myfoo}. Note that the filename given as the last argument to
799 @code{target amd-eb} should be the name of the program as it appears to DOS.
800 In our example this is simply @code{MYFOO}, but in general it can include
801 a DOS path, and depending on your transfer mechanism may not resemble
802 the name on the Unix side.
804 At this point, you can set any breakpoints you wish; when you are ready
805 to see your program run on the 29K board, use the @value{GDBN} command
808 To stop debugging the remote program, use the @value{GDBN} @code{detach}
811 To return control of the PC to its console, use @code{tip} or @code{cu}
812 once again, after your @value{GDBN} session has concluded, to attach to
813 @code{EBMON}. You can then type the command @code{q} to shut down
814 @code{EBMON}, returning control to the DOS command-line interpreter.
815 Type @code{CTTY con} to return command input to the main DOS console,
816 and type @kbd{~.} to leave @code{tip} or @code{cu}.
819 @subsubsection Remote log
821 @cindex log file for EB29K
823 The @code{target amd-eb} command creates a file @file{eb.log} in the
824 current working directory, to help debug problems with the connection.
825 @file{eb.log} records all the output from @code{EBMON}, including echoes
826 of the commands sent to it. Running @samp{tail -f} on this file in
827 another window often helps to understand trouble with @code{EBMON}, or
828 unexpected events on the PC side of the connection.
834 @subsection @value{GDBN} with a Tandem ST2000
836 To connect your ST2000 to the host system, see the manufacturer's
837 manual. Once the ST2000 is physically attached, you can run
840 target st2000 @var{dev} @var{speed}
844 to establish it as your debugging environment. @var{dev} is normally
845 the name of a serial device, such as @file{/dev/ttya}, connected to the
846 ST2000 via a serial line. You can instead specify @var{dev} as a TCP
847 connection (for example, to a serial line attached via a terminal
848 concentrator) using the syntax @code{@var{hostname}:@var{portnumber}}.
850 The @code{load} and @code{attach} commands are @emph{not} defined for
851 this target; you must load your program into the ST2000 as you normally
852 would for standalone operation. @value{GDBN} will read debugging information
853 (such as symbols) from a separate, debugging version of the program
854 available on your host computer.
855 @c FIXME!! This is terribly vague; what little content is here is
856 @c basically hearsay.
858 @cindex ST2000 auxiliary commands
859 These auxiliary @value{GDBN} commands are available to help you with the ST2000
863 @item st2000 @var{command}
864 @kindex st2000 @var{cmd}
865 @cindex STDBUG commands (ST2000)
866 @cindex commands to STDBUG (ST2000)
867 Send a @var{command} to the STDBUG monitor. See the manufacturer's
868 manual for available commands.
871 @cindex connect (to STDBUG)
872 Connect the controlling terminal to the STDBUG command monitor. When
873 you are done interacting with STDBUG, typing either of two character
874 sequences will get you back to the @value{GDBN} command prompt:
875 @kbd{@key{RET}~.} (Return, followed by tilde and period) or
876 @kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D).
882 @subsection @value{GDBN} and VxWorks
885 @value{GDBN} enables developers to spawn and debug tasks running on networked
886 VxWorks targets from a Unix host. Already-running tasks spawned from
887 the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on
888 both the Unix host and on the VxWorks target. The program
889 @code{gdb} is installed and executed on the Unix host. (It may be
890 installed with the name @code{vxgdb}, to distinguish it from a
891 @value{GDBN} for debugging programs on the host itself.)
893 The following information on connecting to VxWorks was current when
894 this manual was produced; newer releases of VxWorks may use revised
897 The remote debugging interface (RDB) routines are installed and executed
898 on the VxWorks target. These routines are included in the VxWorks library
899 @file{rdb.a} and are incorporated into the system image when source-level
900 debugging is enabled in the VxWorks configuration.
903 If you wish, you can define @code{INCLUDE_RDB} in the VxWorks
904 configuration file @file{configAll.h} to include the RDB interface
905 routines and spawn the source debugging task @code{tRdbTask} when
906 VxWorks is booted. For more information on configuring and remaking
907 VxWorks, see the manufacturer's manual.
908 @c VxWorks, see the @cite{VxWorks Programmer's Guide}.
910 Once you have included the RDB interface in your VxWorks system image
911 and set your Unix execution search path to find @value{GDBN}, you are ready
912 to run @value{GDBN}. From your Unix host, run @code{gdb} (or
913 @code{vxgdb}, depending on your installation).
915 @value{GDBN} comes up showing the prompt:
922 * VxWorks Connection:: Connecting to VxWorks
923 * VxWorks Download:: VxWorks download
924 * VxWorks Attach:: Running tasks
927 @node VxWorks Connection
928 @subsubsection Connecting to VxWorks
930 The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the
931 network. To connect to a target whose host name is ``@code{tt}'', type:
934 (vxgdb) target vxworks tt
937 @value{GDBN} displays messages like these:
940 Attaching remote machine across net...
944 @value{GDBN} then attempts to read the symbol tables of any object modules
945 loaded into the VxWorks target since it was last booted. @value{GDBN} locates
946 these files by searching the directories listed in the command search
947 path (@pxref{Environment, ,Your program's environment}); if it fails
948 to find an object file, it displays a message such as:
951 prog.o: No such file or directory.
954 When this happens, add the appropriate directory to the search path with
955 the @value{GDBN} command @code{path}, and execute the @code{target}
958 @node VxWorks Download
959 @subsubsection VxWorks download
961 @cindex download to VxWorks
962 If you have connected to the VxWorks target and you want to debug an
963 object that has not yet been loaded, you can use the @value{GDBN}
964 @code{load} command to download a file from Unix to VxWorks
965 incrementally. The object file given as an argument to the @code{load}
966 command is actually opened twice: first by the VxWorks target in order
967 to download the code, then by @value{GDBN} in order to read the symbol
968 table. This can lead to problems if the current working directories on
969 the two systems differ. If both systems have NFS mounted the same
970 filesystems, you can avoid these problems by using absolute paths.
971 Otherwise, it is simplest to set the working directory on both systems
972 to the directory in which the object file resides, and then to reference
973 the file by its name, without any path. For instance, a program
974 @file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks
975 and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this
976 program, type this on VxWorks:
979 -> cd "@var{vxpath}/vw/demo/rdb"
982 Then, in @value{GDBN}, type:
985 (vxgdb) cd @var{hostpath}/vw/demo/rdb
989 @value{GDBN} displays a response similar to this:
992 Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
995 You can also use the @code{load} command to reload an object module
996 after editing and recompiling the corresponding source file. Note that
997 this will cause @value{GDBN} to delete all currently-defined breakpoints,
998 auto-displays, and convenience variables, and to clear the value
999 history. (This is necessary in order to preserve the integrity of
1000 debugger data structures that reference the target system's symbol
1003 @node VxWorks Attach
1004 @subsubsection Running tasks
1006 @cindex running VxWorks tasks
1007 You can also attach to an existing task using the @code{attach} command as
1011 (vxgdb) attach @var{task}
1015 where @var{task} is the VxWorks hexadecimal task ID. The task can be running
1016 or suspended when you attach to it. If running, it will be suspended at
1017 the time of attachment.
1021 @node Hitachi Remote
1022 @subsection @value{GDBN} and Hitachi Microprocessors
1023 @value{GDBN} needs to know these things to talk to your
1024 Hitachi SH, H8/300, or H8/500:
1028 that you want to use @samp{target hms}, the remote debugging interface
1029 for Hitachi microprocessors (this is the default when GDB is configured
1030 specifically for the Hitachi SH, H8/300, or H8/500);
1033 what serial device connects your host to your Hitachi board (the first
1034 serial device available on your host is the default);
1037 @c this is only for Unix hosts, not currently of interest.
1039 what speed to use over the serial device.
1043 @ifclear H8EXCLUSIVE
1044 @c only for Unix hosts
1046 @cindex serial device, Hitachi micros
1047 Use the special @code{@value{GDBP}} command @samp{device @var{port}} if you
1048 need to explicitly set the serial device. The default @var{port} is the
1049 first available port on your host. This is only necessary on Unix
1050 hosts, where it is typically something like @file{/dev/ttya}.
1053 @cindex serial line speed, Hitachi micros
1054 @code{@value{GDBP}} has another special command to set the communications
1055 speed: @samp{speed @var{bps}}. This command also is only used from Unix
1056 hosts; on DOS hosts, set the line speed as usual from outside GDB with
1057 the DOS @kbd{mode} command (for instance, @w{@samp{mode
1058 com2:9600,n,8,1,p}} for a 9600 bps connection).
1060 The @samp{device} and @samp{speed} commands are available only when you
1061 use a Unix host to debug your Hitachi microprocessor programs. If you
1064 @value{GDBN} depends on an auxiliary terminate-and-stay-resident program
1065 called @code{asynctsr} to communicate with the development board
1066 through a PC serial port. You must also use the DOS @code{mode} command
1067 to set up the serial port on the DOS side.
1070 The following sample session illustrates the steps needed to start a
1071 program under @value{GDBN} control on an H8/300. The example uses a
1072 sample H8/300 program called @file{t.x}. The procedure is the same for
1073 the Hitachi SH and the H8/500.
1075 First hook up your development board. In this example, we use a
1076 board attached to serial port @code{COM2}; if you use a different serial
1077 port, substitute its name in the argument of the @code{mode} command.
1078 When you call @code{asynctsr}, the auxiliary comms program used by the
1079 degugger, you give it just the numeric part of the serial port's name;
1080 for example, @samp{asyncstr 2} below runs @code{asyncstr} on
1084 (eg-C:\H8300\TEST) mode com2:9600,n,8,1,p
1086 Resident portion of MODE loaded
1088 COM2: 9600, n, 8, 1, p
1090 (eg-C:\H8300\TEST) asynctsr 2
1094 @emph{Warning:} We have noticed a bug in PC-NFS that conflicts with
1095 @code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to
1096 disable it, or even boot without it, to use @code{asynctsr} to control
1097 your development board.
1101 Now that serial communications are set up, and the development board is
1102 connected, you can start up @value{GDBN}. Call @code{@value{GDBP}} with
1103 the name of your program as the argument. @code{@value{GDBP}} prompts
1104 you, as usual, with the prompt @samp{(@value{GDBP})}. Use two special
1105 commands to begin your debugging session: @samp{target hms} to specify
1106 cross-debugging to the Hitachi board, and the @code{load} command to
1107 download your program to the board. @code{load} displays the names of
1108 the program's sections, and a @samp{*} for each 2K of data downloaded.
1109 (If you want to refresh @value{GDBN} data on symbols or on the
1110 executable file without downloading, use the @value{GDBN} commands
1111 @code{file} or @code{symbol-file}. These commands, and @code{load}
1112 itself, are described in @ref{Files,,Commands to specify files}.)
1115 (eg-C:\H8300\TEST) @value{GDBP} t.x
1116 GDB is free software and you are welcome to distribute copies
1117 of it under certain conditions; type "show copying" to see
1119 There is absolutely no warranty for GDB; type "show warranty"
1121 GDB @value{GDBVN}, Copyright 1992 Free Software Foundation, Inc...
1123 Connected to remote H8/300 HMS system.
1125 .text : 0x8000 .. 0xabde ***********
1126 .data : 0xabde .. 0xad30 *
1127 .stack : 0xf000 .. 0xf014 *
1130 At this point, you're ready to run or debug your program. From here on,
1131 you can use all the usual @value{GDBN} commands. The @code{break} command
1132 sets breakpoints; the @code{run} command starts your program;
1133 @code{print} or @code{x} display data; the @code{continue} command
1134 resumes execution after stopping at a breakpoint. You can use the
1135 @code{help} command at any time to find out more about @value{GDBN} commands.
1137 Remember, however, that @emph{operating system} facilities aren't
1138 available on your development board; for example, if your program hangs,
1139 you can't send an interrupt---but you can press the @sc{reset} switch!
1141 Use the @sc{reset} button on the development board
1144 to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has
1145 no way to pass an interrupt signal to the development board); and
1148 to return to the @value{GDBN} command prompt after your program finishes
1149 normally. The communications protocol provides no other way for @value{GDBN}
1150 to detect program completion.
1153 In either case, @value{GDBN} will see the effect of a @sc{reset} on the
1154 development board as a ``normal exit'' of your program.
1160 @subsection @value{GDBN} and remote MIPS boards
1163 @value{GDBN} can use the MIPS remote debugging protocol to talk to a
1164 MIPS board attached to a serial line. This is available when
1165 you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}.
1167 @kindex target mips @var{port}
1168 To run a program on the board, start up @code{@value{GDBP}} with the
1169 name of your program as the argument. To connect to the board, use the
1170 command @samp{target mips @var{port}}, where @var{port} is the name of
1171 the serial port connected to the board. If the program has not already
1172 been downloaded to the board, you may use the @code{load} command to
1173 download it. You can then use all the usual @value{GDBN} commands.
1175 You can also specify @var{port} as a TCP connection (for instance, to a
1176 serial line managed by a terminal concentrator), using the syntax
1177 @code{@var{hostname}:@var{portnumber}}.
1179 @cindex @code{remotedebug}, MIPS protocol
1180 @c FIXME! For this to be useful, you must know something about the MIPS
1181 @c FIXME...protocol. Where is it described?
1182 You can see some debugging information about communications with the board
1183 by setting the @code{remotedebug} variable. If you set it to 1 using
1184 @samp{set remotedebug 1} every packet will be displayed. If you set it
1185 to 2 every character will be displayed. You can check the current value
1186 at any time with the command @samp{show remotedebug}.
1188 @cindex @code{timeout}, MIPS protocol
1189 @cindex @code{retransmit-timeout}, MIPS protocol
1191 @kindex show timeout
1192 @kindex set retransmit-timeout
1193 @kindex show retransmit-timeout
1194 You can control the timeout used while waiting for a packet, in the MIPS
1195 remote protocol, with the @code{set timeout @var{seconds}} command. The
1196 default is 5 seconds. Similarly, you can control the timeout used while
1197 waiting for an acknowledgement of a packet with the @code{set
1198 retransmit-timeout @var{seconds}} command. The default is 3 seconds.
1199 You can inspect both values with @code{show timeout} and @code{show
1200 retransmit-timeout}. (These commands are @emph{only} available when
1201 @value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.)
1203 @kindex set mipsfpu off
1204 @cindex MIPS remote floating point
1205 @cindex floating point, MIPS remote
1206 If your target board does not support the MIPS floating point
1207 coprocessor, you should use the command @samp{set mipsfpu off} (you may
1208 wish to put this in your @value{GDBINIT} file). This tells @value{GDBN}
1209 how to find the return value of functions which return floating point
1210 values. It also allows @value{GDBN} to avoid saving the floating point
1211 registers when calling functions on the board.
1216 @subsection Simulated CPU target
1220 @cindex simulator, Z8000
1221 @cindex Z8000 simulator
1222 @cindex simulator, H8/300 or H8/500
1223 @cindex H8/300 or H8/500 simulator
1224 @cindex simulator, Hitachi SH
1225 @cindex Hitachi SH simulator
1226 @cindex CPU simulator
1227 For some configurations, @value{GDBN} includes a CPU simulator that you
1228 can use instead of a hardware CPU to debug your programs. Currently,
1229 a simulator is available when @value{GDBN} is configured to debug Zilog
1230 Z8000 or Hitachi microprocessor targets.
1235 @cindex simulator, H8/300 or H8/500
1236 @cindex Hitachi H8/300 or H8/500 simulator
1237 @cindex simulator, Hitachi SH
1238 @cindex Hitachi SH simulator
1239 When configured for debugging Hitachi microprocessor targets,
1240 @value{GDBN} includes a CPU simulator for the target chip (a Hitachi SH,
1245 @cindex simulator, Z8000
1246 @cindex Zilog Z8000 simulator
1247 When configured for debugging Zilog Z8000 targets, @value{GDBN} includes
1253 For the Z8000 family, @samp{target sim} simulates either the Z8002 (the
1254 unsegmented variant of the Z8000 architecture) or the Z8001 (the
1255 segmented variant). The simulator recognizes which architecture is
1256 appropriate by inspecting the object code.
1263 Debug programs on a simulated CPU
1265 (which CPU depends on the @value{GDBN} configuration)
1270 After specifying this target, you can debug programs for the simulated
1271 CPU in the same style as programs for your host computer; use the
1272 @code{file} command to load a new program image, the @code{run} command
1273 to run your program, and so on.
1275 As well as making available all the usual machine registers (see
1276 @code{info reg}), this debugging target provides three additional items
1277 of information as specially named registers:
1281 Counts clock-ticks in the simulator.
1284 Counts instructions run in the simulator.
1287 Execution time in 60ths of a second.
1290 You can refer to these values in @value{GDBN} expressions with the usual
1291 conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a
1292 conditional breakpoint that will suspend only after at least 5000
1293 simulated clock ticks.