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 The debugging stub is specific to the architecture of the remote
52 machine; for example, use @file{sparc-stub.c} to debug programs on
55 @cindex remote serial stub list
56 These working remote stubs are distributed with @value{GDBN}:
61 For @sc{sparc} architectures.
65 @kindex Motorola 680x0
67 For Motorola 680x0 architectures.
73 For Intel 386 and compatible architectures.
76 The @file{README} file in the @value{GDBN} distribution may list other
80 * Stub Contents:: What the stub can do for you
81 * Bootstrapping:: What you must do for the stub
82 * Debug Session:: Putting it all together
83 * Protocol:: Outline of the communication protocol
87 @subsubsection What the stub can do for you
89 @cindex remote serial stub
90 The debugging stub for your architecture supplies these three
95 @kindex set_debug_traps
96 @cindex remote serial stub, initialization
97 This routine arranges for @code{handle_exception} to run when your
98 program stops. You must call this subroutine explicitly near the
99 beginning of your program.
101 @item handle_exception
102 @kindex handle_exception
103 @cindex remote serial stub, main routine
104 This is the central workhorse, but your program never calls it
105 explicitly---the setup code arranges for @code{handle_exception} to
106 run when a trap is triggered.
108 @code{handle_exception} takes control when your program stops during
109 execution (for example, on a breakpoint), and mediates communications
110 with @value{GDBN} on the host machine. This is where the communications
111 protocol is implemented; @code{handle_exception} acts as the @value{GDBN}
112 representative on the target machine; it begins by sending summary
113 information on the state of your program, then continues to execute,
114 retrieving and transmitting any information @value{GDBN} needs, until you
115 execute a @value{GDBN} command that makes your program resume; at that point,
116 @code{handle_exception} returns control to your own code on the target
120 @cindex @code{breakpoint} subroutine, remote
121 Use this auxiliary subroutine to make your program contain a
122 breakpoint. Depending on the particular situation, this may be the only
123 way for @value{GDBN} to get control. For instance, if your target
124 machine has some sort of interrupt button, you won't need to call this;
125 pressing the interrupt button will transfer control to
126 @code{handle_exception}---in efect, to @value{GDBN}. On some machines,
127 simply receiving characters on the serial port may also trigger a trap;
128 again, in that situation, you don't need to call @code{breakpoint} from
129 your own program---simply running @samp{target remote} from the host
130 @value{GDBN} session will get control.
132 Call @code{breakpoint} if none of these is true, or if you simply want
133 to make certain your program stops at a predetermined point for the
134 start of your debugging session.
138 @subsubsection What you must do for the stub
140 @cindex remote stub, support routines
141 The debugging stubs that come with @value{GDBN} are set up for a particular
142 chip architecture, but they have no information about the rest of your
143 debugging target machine. To allow the stub to work, you must supply
144 these special low-level subroutines:
147 @item int getDebugChar()
149 Write this subroutine to read a single character from the serial port.
150 It may be identical to @code{getchar} for your target system; a
151 different name is used to allow you to distinguish the two if you wish.
153 @item void putDebugChar(int)
155 Write this subroutine to write a single character to the serial port.
156 It may be identical to @code{putchar} for your target system; a
157 different name is used to allow you to distinguish the two if you wish.
159 @item void flush_i_cache()
160 @kindex flush_i_cache
161 Write this subroutine to flush the instruction cache, if any, on your
162 target machine. If there is no instruction cache, this subroutine may
165 On target machines that have instruction caches, @value{GDBN} requires this
166 function to make certain that the state of your program is stable.
170 You must also make sure this library routine is available:
173 @item void *memset(void *, int, int)
175 This is the standard library function @code{memset} that sets an area of
176 memory to a known value. If you have one of the free versions of
177 @code{libc.a}, @code{memset} can be found there; otherwise, you must
178 either obtain it from your hardware manufacturer, or write your own.
181 If you do not use the GNU C compiler, you may need other standard
182 library subroutines as well; this will vary from one stub to another,
183 but in general the stubs are likely to use any of the common library
184 subroutines which @code{gcc} generates as inline code.
188 @subsubsection Putting it all together
190 @cindex remote serial debugging summary
191 In summary, when your program is ready to debug, you must follow these
196 Make sure you have the supporting low-level routines:
198 @code{getDebugChar}, @code{putDebugChar},
199 @code{flush_i_cache}, @code{memset}.
203 Insert these lines near the top of your program:
211 For the 680x0 stub only, you need to provide a variable called
212 exceptionHook. Normally you just use
215 void (*exceptionHook)() = 0;
218 but if you, before calling @code{set_debug_traps}, set it to point to
219 a function, that function will be called when the debugger continues
220 from a trap (for example, bus error) which causes the debugger to be
221 entered. It is passed one parameter---an @code{int} which is the
225 Compile and link together: your program, the @value{GDBN} debugging stub for
226 your target architecture, and the supporting subroutines.
229 Make sure you have a serial connection between your target machine and
230 the @value{GDBN} host, and identify the serial port used for this on the host.
233 Download your program to your target machine (or get it there by
234 whatever means the manufacturer provides), and start it.
237 To start remote debugging, run @value{GDBN} on the host machine, and specify
238 as an executable file the program that is running in the remote machine.
239 This tells @value{GDBN} how to find your program's symbols and the contents
242 Then establish communication using the @code{target remote} command.
243 Its argument is the name of the device you're using to control the
244 target machine. For example:
247 target remote /dev/ttyb
251 if the serial line is connected to the device named @file{/dev/ttyb}.
253 @c this is from the old text, but it doesn't seem to make sense now that I've
254 @c seen an example... pesch 4sep1992
255 This will stop the remote machine if it is not already stopped.
259 Now you can use all the usual commands to examine and change data and to
260 step and continue the remote program.
262 To resume the remote program and stop debugging it, use the @code{detach}
265 @cindex interrupting remote programs
266 @cindex remote programs, interrupting
267 Whenever @value{GDBN} is waiting for the remote program, if you type the
268 interrupt character (often @key{C-C}), @value{GDBN} attempts to stop the
269 program. This may or may not succeed, depending in part on the hardware
270 and the serial drivers the remote system uses. If you type the
271 interrupt character once again, @value{GDBN} displays this prompt:
274 Interrupted while waiting for the program.
275 Give up (and stop debugging it)? (y or n)
278 If you type @kbd{y}, @value{GDBN} abandons the remote debugging session.
279 (If you decide you want to try again later, you can use @samp{target
280 remote} again to connect once more.) If you type @kbd{n}, @value{GDBN}
281 goes back to waiting.
284 @subsubsection Outline of the communication protocol
286 @cindex debugging stub, example
287 @cindex remote stub, example
288 @cindex stub example, remote debugging
289 The stub files provided with @value{GDBN} implement the target side of the
290 communication protocol, and the @value{GDBN} side is implemented in the
291 @value{GDBN} source file @file{remote.c}. Normally, you can simply allow
292 these subroutines to communicate, and ignore the details. (If you're
293 implementing your own stub file, you can still ignore the details: start
294 with one of the existing stub files. @file{sparc-stub.c} is the best
295 organized, and therefore the easiest to read.)
297 However, there may be occasions when you need to know something about
298 the protocol---for example, if there is only one serial port to your
299 target machine, you might want your program to do something special if
300 it recognizes a packet meant for @value{GDBN}.
302 @cindex protocol, @value{GDBN} remote serial
303 @cindex serial protocol, @value{GDBN} remote
304 @cindex remote serial protocol
305 All @value{GDBN} commands and responses (other than acknowledgements, which
306 are single characters) are sent as a packet which includes a
307 checksum. A packet is introduced with the character @samp{$}, and ends
308 with the character @samp{#} followed by a two-digit checksum:
311 $@var{packet info}#@var{checksum}
314 @cindex checksum, for @value{GDBN} remote
316 @var{checksum} is computed as the modulo 256 sum of the @var{packet
319 When either the host or the target machine receives a packet, the first
320 response expected is an acknowledgement: a single character, either
321 @samp{+} (to indicate the package was received correctly) or @samp{-}
322 (to request retransmission).
324 The host (@value{GDBN}) sends commands, and the target (the debugging stub
325 incorporated in your program) sends data in response. The target also
326 sends data when your program stops.
328 Command packets are distinguished by their first character, which
329 identifies the kind of command.
331 These are the commands currently supported:
335 Requests the values of CPU registers.
338 Sets the values of CPU registers.
340 @item m@var{addr},@var{count}
341 Read @var{count} bytes at location @var{addr}.
343 @item M@var{addr},@var{count}:@dots{}
344 Write @var{count} bytes at location @var{addr}.
348 Resume execution at the current address (or at @var{addr} if supplied).
352 Step the target program for one instruction, from either the current
353 program counter or from @var{addr} if supplied.
356 Kill the target program.
359 Report the most recent signal. To allow you to take advantage of the
360 @value{GDBN} signal handling commands, one of the functions of the debugging
361 stub is to report CPU traps as the corresponding POSIX signal values.
364 @kindex set remotedebug
365 @kindex show remotedebug
366 @cindex packets, reporting on stdout
367 @cindex serial connections, debugging
368 If you have trouble with the serial connection, you can use the command
369 @code{set remotedebug}. This makes @value{GDBN} report on all packets sent
370 back and forth across the serial line to the remote machine. The
371 packet-debugging information is printed on the @value{GDBN} standard output
372 stream. @code{set remotedebug off} turns it off, and @code{show
373 remotedebug} will show you its current state.
377 @node i960-Nindy Remote
378 @subsection @value{GDBN} with a remote i960 (Nindy)
382 @dfn{Nindy} is a ROM Monitor program for Intel 960 target systems. When
383 @value{GDBN} is configured to control a remote Intel 960 using Nindy, you can
384 tell @value{GDBN} how to connect to the 960 in several ways:
388 Through command line options specifying serial port, version of the
389 Nindy protocol, and communications speed;
392 By responding to a prompt on startup;
395 By using the @code{target} command at any point during your @value{GDBN}
396 session. @xref{Target Commands, ,Commands for managing targets}.
401 * Nindy Startup:: Startup with Nindy
402 * Nindy Options:: Options for Nindy
403 * Nindy Reset:: Nindy reset command
407 @subsubsection Startup with Nindy
409 If you simply start @code{@value{GDBP}} without using any command-line
410 options, you are prompted for what serial port to use, @emph{before} you
411 reach the ordinary @value{GDBN} prompt:
414 Attach /dev/ttyNN -- specify NN, or "quit" to quit:
418 Respond to the prompt with whatever suffix (after @samp{/dev/tty})
419 identifies the serial port you want to use. You can, if you choose,
420 simply start up with no Nindy connection by responding to the prompt
421 with an empty line. If you do this and later wish to attach to Nindy,
422 use @code{target} (@pxref{Target Commands, ,Commands for managing targets}).
425 @subsubsection Options for Nindy
427 These are the startup options for beginning your @value{GDBN} session with a
428 Nindy-960 board attached:
432 Specify the serial port name of a serial interface to be used to connect
433 to the target system. This option is only available when @value{GDBN} is
434 configured for the Intel 960 target architecture. You may specify
435 @var{port} as any of: a full pathname (e.g. @samp{-r /dev/ttya}), a
436 device name in @file{/dev} (e.g. @samp{-r ttya}), or simply the unique
437 suffix for a specific @code{tty} (e.g. @samp{-r a}).
440 (An uppercase letter ``O'', not a zero.) Specify that @value{GDBN} should use
441 the ``old'' Nindy monitor protocol to connect to the target system.
442 This option is only available when @value{GDBN} is configured for the Intel 960
446 @emph{Warning:} if you specify @samp{-O}, but are actually trying to
447 connect to a target system that expects the newer protocol, the connection
448 fails, appearing to be a speed mismatch. @value{GDBN} repeatedly
449 attempts to reconnect at several different line speeds. You can abort
450 this process with an interrupt.
454 Specify that @value{GDBN} should first send a @code{BREAK} signal to the target
455 system, in an attempt to reset it, before connecting to a Nindy target.
458 @emph{Warning:} Many target systems do not have the hardware that this
459 requires; it only works with a few boards.
463 The standard @samp{-b} option controls the line speed used on the serial
468 @subsubsection Nindy reset command
473 For a Nindy target, this command sends a ``break'' to the remote target
474 system; this is only useful if the target has been equipped with a
475 circuit to perform a hard reset (or some other interesting action) when
483 @subsection @value{GDBN} and the UDI protocol for AMD29K
486 @cindex AMD29K via UDI
487 @value{GDBN} supports AMD's UDI (``Universal Debugger Interface'')
488 protocol for debugging the a29k processor family. To use this
489 configuration with AMD targets running the MiniMON monitor, you need the
490 program @code{MONTIP}, available from AMD at no charge. You can also
491 use @value{GDBN} with the UDI conformant a29k simulator program
492 @code{ISSTIP}, also available from AMD.
495 @item target udi @var{keyword}
497 Select the UDI interface to a remote a29k board or simulator, where
498 @var{keyword} is an entry in the AMD configuration file @file{udi_soc}.
499 This file contains keyword entries which specify parameters used to
500 connect to a29k targets. If the @file{udi_soc} file is not in your
501 working directory, you must set the environment variable @samp{UDICONF}
506 @subsection @value{GDBN} with a remote EB29K
509 @cindex running 29K programs
511 To use @value{GDBN} from a Unix system to run programs on AMD's EB29K
512 board in a PC, you must first connect a serial cable between the PC
513 and a serial port on the Unix system. In the following, we assume
514 you've hooked the cable between the PC's @file{COM1} port and
515 @file{/dev/ttya} on the Unix system.
518 * Comms (EB29K):: Communications setup
519 * gdb-EB29K:: EB29K cross-debugging
520 * Remote Log:: Remote log
524 @subsubsection Communications setup
526 The next step is to set up the PC's port, by doing something like this
530 C:\> MODE com1:9600,n,8,1,none
534 This example---run on an MS DOS 4.0 system---sets the PC port to 9600
535 bps, no parity, eight data bits, one stop bit, and no ``retry'' action;
536 you must match the communications parameters when establishing the Unix
537 end of the connection as well.
538 @c FIXME: Who knows what this "no retry action" crud from the DOS manual may
539 @c mean? It's optional; leave it out? ---pesch@cygnus.com, 25feb91
541 To give control of the PC to the Unix side of the serial line, type
542 the following at the DOS console:
549 (Later, if you wish to return control to the DOS console, you can use
550 the command @code{CTTY con}---but you must send it over the device that
551 had control, in our example over the @file{COM1} serial line).
553 From the Unix host, use a communications program such as @code{tip} or
554 @code{cu} to communicate with the PC; for example,
557 cu -s 9600 -l /dev/ttya
561 The @code{cu} options shown specify, respectively, the linespeed and the
562 serial port to use. If you use @code{tip} instead, your command line
563 may look something like the following:
570 Your system may require a different name where we show
571 @file{/dev/ttya} as the argument to @code{tip}. The communications
572 parameters, including which port to use, are associated with the
573 @code{tip} argument in the ``remote'' descriptions file---normally the
574 system table @file{/etc/remote}.
575 @c FIXME: What if anything needs doing to match the "n,8,1,none" part of
576 @c the DOS side's comms setup? cu can support -o (odd
577 @c parity), -e (even parity)---apparently no settings for no parity or
578 @c for character size. Taken from stty maybe...? John points out tip
579 @c can set these as internal variables, eg ~s parity=none; man stty
580 @c suggests that it *might* work to stty these options with stdin or
581 @c stdout redirected... ---pesch@cygnus.com, 25feb91
584 Using the @code{tip} or @code{cu} connection, change the DOS working
585 directory to the directory containing a copy of your 29K program, then
586 start the PC program @code{EBMON} (an EB29K control program supplied
587 with your board by AMD). You should see an initial display from
588 @code{EBMON} similar to the one that follows, ending with the
589 @code{EBMON} prompt @samp{#}---
594 G:\> CD \usr\joe\work29k
596 G:\USR\JOE\WORK29K> EBMON
597 Am29000 PC Coprocessor Board Monitor, version 3.0-18
598 Copyright 1990 Advanced Micro Devices, Inc.
599 Written by Gibbons and Associates, Inc.
601 Enter '?' or 'H' for help
603 PC Coprocessor Type = EB29K
605 Memory Base = 0xd0000
607 Data Memory Size = 2048KB
608 Available I-RAM Range = 0x8000 to 0x1fffff
609 Available D-RAM Range = 0x80002000 to 0x801fffff
612 Register Stack Size = 0x800
613 Memory Stack Size = 0x1800
616 Am29027 Available = No
617 Byte Write Available = Yes
622 Then exit the @code{cu} or @code{tip} program (done in the example by
623 typing @code{~.} at the @code{EBMON} prompt). @code{EBMON} will keep
624 running, ready for @value{GDBN} to take over.
626 For this example, we've assumed what is probably the most convenient
627 way to make sure the same 29K program is on both the PC and the Unix
628 system: a PC/NFS connection that establishes ``drive @code{G:}'' on the
629 PC as a file system on the Unix host. If you do not have PC/NFS or
630 something similar connecting the two systems, you must arrange some
631 other way---perhaps floppy-disk transfer---of getting the 29K program
632 from the Unix system to the PC; @value{GDBN} will @emph{not} download it over the
636 @subsubsection EB29K cross-debugging
638 Finally, @code{cd} to the directory containing an image of your 29K
639 program on the Unix system, and start @value{GDBN}---specifying as argument the
640 name of your 29K program:
647 Now you can use the @code{target} command:
650 target amd-eb /dev/ttya 9600 MYFOO
651 @c FIXME: test above 'target amd-eb' as spelled, with caps! caps are meant to
652 @c emphasize that this is the name as seen by DOS (since I think DOS is
653 @c single-minded about case of letters). ---pesch@cygnus.com, 25feb91
657 In this example, we've assumed your program is in a file called
658 @file{myfoo}. Note that the filename given as the last argument to
659 @code{target amd-eb} should be the name of the program as it appears to DOS.
660 In our example this is simply @code{MYFOO}, but in general it can include
661 a DOS path, and depending on your transfer mechanism may not resemble
662 the name on the Unix side.
664 At this point, you can set any breakpoints you wish; when you are ready
665 to see your program run on the 29K board, use the @value{GDBN} command
668 To stop debugging the remote program, use the @value{GDBN} @code{detach}
671 To return control of the PC to its console, use @code{tip} or @code{cu}
672 once again, after your @value{GDBN} session has concluded, to attach to
673 @code{EBMON}. You can then type the command @code{q} to shut down
674 @code{EBMON}, returning control to the DOS command-line interpreter.
675 Type @code{CTTY con} to return command input to the main DOS console,
676 and type @kbd{~.} to leave @code{tip} or @code{cu}.
679 @subsubsection Remote log
681 @cindex log file for EB29K
683 The @code{target amd-eb} command creates a file @file{eb.log} in the
684 current working directory, to help debug problems with the connection.
685 @file{eb.log} records all the output from @code{EBMON}, including echoes
686 of the commands sent to it. Running @samp{tail -f} on this file in
687 another window often helps to understand trouble with @code{EBMON}, or
688 unexpected events on the PC side of the connection.
694 @subsection @value{GDBN} with a Tandem ST2000
696 To connect your ST2000 to the host system, see the manufacturer's
697 manual. Once the ST2000 is physically attached, you can run
700 target st2000 @var{dev} @var{speed}
704 to establish it as your debugging environment.
706 The @code{load} and @code{attach} commands are @emph{not} defined for
707 this target; you must load your program into the ST2000 as you normally
708 would for standalone operation. @value{GDBN} will read debugging information
709 (such as symbols) from a separate, debugging version of the program
710 available on your host computer.
711 @c FIXME!! This is terribly vague; what little content is here is
712 @c basically hearsay.
714 @cindex ST2000 auxiliary commands
715 These auxiliary @value{GDBN} commands are available to help you with the ST2000
719 @item st2000 @var{command}
720 @kindex st2000 @var{cmd}
721 @cindex STDBUG commands (ST2000)
722 @cindex commands to STDBUG (ST2000)
723 Send a @var{command} to the STDBUG monitor. See the manufacturer's
724 manual for available commands.
727 @cindex connect (to STDBUG)
728 Connect the controlling terminal to the STDBUG command monitor. When
729 you are done interacting with STDBUG, typing either of two character
730 sequences will get you back to the @value{GDBN} command prompt:
731 @kbd{@key{RET}~.} (Return, followed by tilde and period) or
732 @kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D).
738 @subsection @value{GDBN} and VxWorks
741 @value{GDBN} enables developers to spawn and debug tasks running on networked
742 VxWorks targets from a Unix host. Already-running tasks spawned from
743 the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on
744 both the UNIX host and on the VxWorks target. The program
745 @code{@value{GDBP}} is installed and executed on the UNIX host.
747 The following information on connecting to VxWorks was current when
748 this manual was produced; newer releases of VxWorks may use revised
751 The remote debugging interface (RDB) routines are installed and executed
752 on the VxWorks target. These routines are included in the VxWorks library
753 @file{rdb.a} and are incorporated into the system image when source-level
754 debugging is enabled in the VxWorks configuration.
757 If you wish, you can define @code{INCLUDE_RDB} in the VxWorks
758 configuration file @file{configAll.h} to include the RDB interface
759 routines and spawn the source debugging task @code{tRdbTask} when
760 VxWorks is booted. For more information on configuring and remaking
761 VxWorks, see the manufacturer's manual.
762 @c VxWorks, see the @cite{VxWorks Programmer's Guide}.
764 Once you have included the RDB interface in your VxWorks system image
765 and set your Unix execution search path to find @value{GDBN}, you are ready
766 to run @value{GDBN}. From your UNIX host, type:
772 @value{GDBN} will come up showing the prompt:
779 * VxWorks Connection:: Connecting to VxWorks
780 * VxWorks Download:: VxWorks download
781 * VxWorks Attach:: Running tasks
784 @node VxWorks Connection
785 @subsubsection Connecting to VxWorks
787 The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the
788 network. To connect to a target whose host name is ``@code{tt}'', type:
791 (@value{GDBP}) target vxworks tt
794 @value{GDBN} will display a message similar to the following:
797 Attaching remote machine across net... Success!
800 @value{GDBN} will then attempt to read the symbol tables of any object modules
801 loaded into the VxWorks target since it was last booted. @value{GDBN} locates
802 these files by searching the directories listed in the command search
803 path (@pxref{Environment, ,Your program's environment}); if it fails
804 to find an object file, it will display a message such as:
807 prog.o: No such file or directory.
810 This will cause the @code{target} command to abort. When this happens,
811 you should add the appropriate directory to the search path, with the
812 @value{GDBN} command @code{path}, and execute the @code{target} command
815 @node VxWorks Download
816 @subsubsection VxWorks download
818 @cindex download to VxWorks
819 If you have connected to the VxWorks target and you want to debug an
820 object that has not yet been loaded, you can use the @value{GDBN} @code{load}
821 command to download a file from UNIX to VxWorks incrementally. The
822 object file given as an argument to the @code{load} command is actually
823 opened twice: first by the VxWorks target in order to download the code,
824 then by @value{GDBN} in order to read the symbol table. This can lead to
825 problems if the current working directories on the two systems differ.
826 It is simplest to set the working directory on both systems to the
827 directory in which the object file resides, and then to reference the
828 file by its name, without any path. Thus, to load a program
829 @file{prog.o}, residing in @file{wherever/vw/demo/rdb}, on VxWorks type:
832 -> cd "wherever/vw/demo/rdb"
835 On @value{GDBN} type:
838 (@value{GDBP}) cd wherever/vw/demo/rdb
839 (@value{GDBP}) load prog.o
842 @value{GDBN} will display a response similar to the following:
845 Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
848 You can also use the @code{load} command to reload an object module
849 after editing and recompiling the corresponding source file. Note that
850 this will cause @value{GDBN} to delete all currently-defined breakpoints,
851 auto-displays, and convenience variables, and to clear the value
852 history. (This is necessary in order to preserve the integrity of
853 debugger data structures that reference the target system's symbol
857 @subsubsection Running tasks
859 @cindex running VxWorks tasks
860 You can also attach to an existing task using the @code{attach} command as
864 (@value{GDBP}) attach @var{task}
868 where @var{task} is the VxWorks hexadecimal task ID. The task can be running
869 or suspended when you attach to it. If running, it will be suspended at
870 the time of attachment.
875 @subsection @value{GDBN} and Hitachi Microprocessors
876 @value{GDBN} needs to know these things to talk to your
877 Hitachi SH, H8/300, or H8/500:
881 that you want to use @samp{target hms}, the remote debugging interface
882 for Hitachi microprocessors (this is the default when GDB is configured
883 specifically for the Hitachi SH, H8/300, or H8/500);
886 what serial device connects your host to your Hitachi board (the first
887 serial device available on your host is the default);
890 @c this is only for Unix hosts, not currently of interest.
892 what speed to use over the serial device.
897 @c only for Unix hosts
899 @cindex serial device, Hitachi micros
900 Use the special @code{@value{GDBP}} command @samp{device @var{port}} if you
901 need to explicitly set the serial device. The default @var{port} is the
902 first available port on your host. This is only necessary on Unix
903 hosts, where it is typically something like @file{/dev/ttya}.
906 @cindex serial line speed, Hitachi micros
907 @code{@value{GDBP}} has another special command to set the communications
908 speed: @samp{speed @var{bps}}. This command also is only used from Unix
909 hosts; on DOS hosts, set the line speed as usual from outside GDB with
910 the DOS @kbd{mode} command (for instance, @w{@samp{mode
911 com2:9600,n,8,1,p}} for a 9600 bps connection).
913 The @samp{device} and @samp{speed} commands are available only when you
914 use a Unix host to debug your Hitachi microprocessor programs. If you
917 @value{GDBN} depends on an auxiliary terminate-and-stay-resident program
918 called @code{asynctsr} to communicate with the development board
919 through a PC serial port. You must also use the DOS @code{mode} command
920 to set up the serial port on the DOS side.
923 The following sample session illustrates the steps needed to start a
924 program under @value{GDBN} control on an H8/300. The example uses a
925 sample H8/300 program called @file{t.x}. The procedure is the same for
926 the Hitachi SH and the H8/500.
928 First hook up your development board. In this example, we use a
929 board attached to serial port @code{COM2}; if you use a different serial
930 port, substitute its name in the argument of the @code{mode} command.
931 When you call @code{asynctsr}, the auxiliary comms program used by the
932 degugger, you give it just the numeric part of the serial port's name;
933 for example, @samp{asyncstr 2} below runs @code{asyncstr} on
937 (eg-C:\H8300\TEST) mode com2:9600,n,8,1,p
939 Resident portion of MODE loaded
941 COM2: 9600, n, 8, 1, p
943 (eg-C:\H8300\TEST) asynctsr 2
947 @emph{Warning:} We have noticed a bug in PC-NFS that conflicts with
948 @code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to
949 disable it, or even boot without it, to use @code{asynctsr} to control
950 your development board.
954 Now that serial communications are set up, and the development board is
955 connected, you can start up @value{GDBN}. Call @code{@value{GDBP}} with
956 the name of your program as the argument. @code{@value{GDBP}} prompts
957 you, as usual, with the prompt @samp{(@value{GDBP})}. Use two special
958 commands to begin your debugging session: @samp{target hms} to specify
959 cross-debugging to the Hitachi board, and the @code{load} command to
960 download your program to the board. @code{load} displays the names of
961 the program's sections, and a @samp{*} for each 2K of data downloaded.
962 (If you want to refresh @value{GDBN} data on symbols or on the
963 executable file without downloading, use the @value{GDBN} commands
964 @code{file} or @code{symbol-file}. These commands, and @code{load}
965 itself, are described in @ref{Files,,Commands to specify files}.)
968 (eg-C:\H8300\TEST) @value{GDBP} t.x
969 GDB is free software and you are welcome to distribute copies
970 of it under certain conditions; type "show copying" to see
972 There is absolutely no warranty for GDB; type "show warranty"
974 GDB @value{GDBVN}, Copyright 1992 Free Software Foundation, Inc...
976 Connected to remote H8/300 HMS system.
978 .text : 0x8000 .. 0xabde ***********
979 .data : 0xabde .. 0xad30 *
980 .stack : 0xf000 .. 0xf014 *
983 At this point, you're ready to run or debug your program. From here on,
984 you can use all the usual @value{GDBN} commands. The @code{break} command
985 sets breakpoints; the @code{run} command starts your program;
986 @code{print} or @code{x} display data; the @code{continue} command
987 resumes execution after stopping at a breakpoint. You can use the
988 @code{help} command at any time to find out more about @value{GDBN} commands.
990 Remember, however, that @emph{operating system} facilities aren't
991 available on your development board; for example, if your program hangs,
992 you can't send an interrupt---but you can press the @sc{reset} switch!
994 Use the @sc{reset} button on the development board
997 to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has
998 no way to pass an interrupt signal to the development board); and
1001 to return to the @value{GDBN} command prompt after your program finishes
1002 normally. The communications protocol provides no other way for @value{GDBN}
1003 to detect program completion.
1006 In either case, @value{GDBN} will see the effect of a @sc{reset} on the
1007 development board as a ``normal exit'' of your program.
1013 @subsection @value{GDBN} and remote MIPS boards
1016 @value{GDBN} can use the MIPS remote debugging protocol to talk to a
1017 MIPS board attached to a serial line. This is available when
1018 you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}.
1020 @kindex target mips @var{port}
1021 To run a program on the board, start up @code{@value{GDBP}} with the
1022 name of your program as the argument. To connect to the board, use the
1023 command @samp{target mips @var{port}}, where @var{port} is the name of
1024 the serial port connected to the board. If the program has not already
1025 been downloaded to the board, you may use the @code{load} command to
1026 download it. You can then use all the usual @value{GDBN} commands.
1028 @cindex @code{remotedebug}, MIPS protocol
1029 @c FIXME! For this to be useful, you must know something about the MIPS
1030 @c FIXME...protocol. Where is it described?
1031 You can see some debugging information about communications with the board
1032 by setting the @code{remotedebug} variable. If you set it to 1 using
1033 @samp{set remotedebug 1} every packet will be displayed. If you set it
1034 to 2 every character will be displayed. You can check the current value
1035 at any time with the command @samp{show remotedebug}.
1037 @kindex set mipsfpu off
1038 @cindex MIPS remote floating point
1039 @cindex floating point, MIPS remote
1040 If your target board does not support the MIPS floating point
1041 coprocessor, you should use the command @samp{set mipsfpu off} (you may
1042 wish to put this in your @value{GDBINIT} file). This will tell
1043 @value{GDBN} how to find the return value of functions which return
1044 floating point values, and tell it to call functions on the board
1045 without saving the floating point registers.
1050 @subsection Simulated CPU target
1054 @cindex simulator, Z8000
1055 @cindex Z8000 simulator
1056 @cindex simulator, H8/300 or H8/500
1057 @cindex H8/300 or H8/500 simulator
1058 @cindex simulator, Hitachi SH
1059 @cindex Hitachi SH simulator
1060 @cindex CPU simulator
1061 For some configurations, @value{GDBN} includes a CPU simulator that you
1062 can use instead of a hardware CPU to debug your programs. Currently,
1063 a simulator is available when @value{GDBN} is configured to debug Zilog
1064 Z8000 or Hitachi microprocessor targets.
1069 @cindex simulator, H8/300 or H8/500
1070 @cindex Hitachi H8/300 or H8/500 simulator
1071 @cindex simulator, Hitachi SH
1072 @cindex Hitachi SH simulator
1073 When configured for debugging Hitachi microprocessor targets,
1074 @value{GDBN} includes a CPU simulator for the target chip (a Hitachi SH,
1079 @cindex simulator, Z8000
1080 @cindex Zilog Z8000 simulator
1081 When configured for debugging Zilog Z8000 targets, @value{GDBN} includes
1087 For the Z8000 family, @samp{target sim} simulates either the Z8002 (the
1088 unsegmented variant of the Z8000 architecture) or the Z8001 (the
1089 segmented variant). The simulator recognizes which architecture is
1090 appropriate by inspecting the object code.
1097 Debug programs on a simulated CPU
1099 (which CPU depends on the @value{GDBN} configuration)
1104 After specifying this target, you can debug programs for the simulated
1105 CPU in the same style as programs for your host computer; use the
1106 @code{file} command to load a new program image, the @code{run} command
1107 to run your program, and so on.
1109 As well as making available all the usual machine registers (see
1110 @code{info reg}), this debugging target provides three additional items
1111 of information as specially named registers:
1115 Counts clock-ticks in the simulator.
1118 Counts instructions run in the simulator.
1121 Execution time in 60ths of a second.
1124 You can refer to these values in @value{GDBN} expressions with the usual
1125 conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a
1126 conditional breakpoint that will suspend only after at least 5000
1127 simulated clock ticks.