2 _dnl__ Copyright (c) 1990 1991 1992 Free Software Foundation, Inc.
3 _dnl__ This file is part of the source for the GDB manual.
4 _dnl__ M4 FRAGMENT $Id$
5 _dnl__ This text diverted to "Remote Debugging" section in general case;
6 _dnl__ however, if we're doing a manual specifically for one of these, it
7 _dnl__ belongs up front (in "Getting In and Out" chapter).
9 @subsection The _GDBN__ remote serial protocol
11 @cindex remote serial debugging, overview
12 To debug a program running on another machine (the debugging
13 @dfn{target} machine), you must first arrange for all the usual
14 prerequisites for the program to run by itself. For example, for a C
19 A startup routine to set up the C runtime environment; these usually
20 have a name like @file{crt0}. The startup routine may be supplied by
21 your hardware supplier, or you may have to write your own.
24 You probably need a C subroutine library to support your program's
25 subroutine calls, notably managing input and output.
28 A way of getting your program to the other machine---for example, a
29 download program. These are often supplied by the hardware
30 manufacturer, but you may have to write your own from hardware
34 The next step is to arrange for your program to use a serial port to
35 communicate with the machine where _GDBN__ is running (the @dfn{host}
36 machine). In general terms, the scheme looks like this:
40 _GDBN__ already understands how to use this protocol; when everything
41 else is set up, you can simply use the @samp{target remote} command
42 (@pxref{Targets,,Specifying a Debugging Target}).
45 you must link with your program a few special-purpose subroutines that
46 implement the _GDBN__ remote serial protocol. The file containing these
47 subroutines is called a @dfn{debugging stub}.
50 The debugging stub is specific to the architecture of the remote
51 machine; for example, use @file{sparc-stub.c} to debug programs on
54 @cindex remote serial stub list
55 These working remote stubs are distributed with _GDBN__:
57 @c FIXME! verify these...
61 For @sc{sparc} architectures.
65 For Motorola 680x0 architectures.
69 For Intel 386 and compatible architectures.
72 The @file{README} file in the _GDBN__ distribution may list other
76 * stub contents:: What the stub can do for you
77 * bootstrapping:: What you must do for the stub
78 * debug session:: Putting it all together
79 * protocol:: Outline of the communication protocol
83 @subsubsection What the stub can do for you
85 @cindex remote serial stub
86 The debugging stub for your architecture supplies these three
91 @kindex set_debug_traps
92 @cindex remote serial stub, initialization
93 This routine arranges to transfer control to @code{handle_exception}
94 when your program stops. You must call this subroutine explicitly near
95 the beginning of your program.
97 @item handle_exception
98 @kindex handle_exception
99 @cindex remote serial stub, main routine
100 This is the central workhorse, but your program never calls it
101 explicitly---the setup code arranges for @code{handle_exception} to
102 run when a trap is triggered.
104 @code{handle_exception} takes control when your program stops during
105 execution (for example, on a breakpoint), and mediates communications
106 with _GDBN__ on the host machine. This is where the communications
107 protocol is implemented; @code{handle_exception} acts as the _GDBN__
108 representative on the target machine; it begins by sending summary
109 information on the state of your program, then continues to execute,
110 retrieving and transmitting any information _GDBN__ needs, until you
111 execute a _GDBN__ command that makes your program resume; at that point,
112 @code{handle_exception} returns control to your own code on the target
116 @cindex @code{breakpoint} subroutine, remote
117 Use this auxiliary subroutine to make your program contain a
118 breakpoint. Depending on the particular situation, this may be the only
119 way for _GDBN__ to get control. For instance, if your target
120 machine has some sort of interrupt button, you won't need to call this;
121 pressing the interrupt button will transfer control to
122 @code{handle_exception}---in efect, to _GDBN__. On some machines,
123 simply receiving characters on the serial port may also trigger a trap;
124 again, in that situation, you don't need to call @code{breakpoint} from
125 your own program---simply running @samp{target remote} from the host
126 _GDBN__ session will get control.
128 Call @code{breakpoint} if none of these is true, or if you simply want
129 to make certain your program stops at a predetermined point for the
130 start of your debugging session.
134 @subsubsection What you must do for the stub
136 @cindex remote stub, support routines
137 The debugging stubs that come with _GDBN__ are set up for a particular
138 chip architecture, but they have no information about the rest of your
139 debugging target machine. To allow the stub to work, you must supply
140 these special low-level subroutines:
143 @item int getDebugChar()
145 Write this subroutine to read a single character from the serial port.
146 It may be identical to @code{getchar} for your target system; a
147 different name is used to allow you to distinguish the two if you wish.
149 @item void putDebugChar(int)
151 Write this subroutine to write a single character to the serial port.
152 It may be identical to @code{putchar} for your target system; a
153 different name is used to allow you to distinguish the two if you wish.
155 @item void flush_i_cache()
156 @kindex flush_i_cache
157 Write this subroutine to flush the instruction cache, if any, on your
158 target machine. If there is no instruction cache, this subroutine may
161 On target machines that have instruction caches, _GDBN__ requires this
162 function to make certain that the state of your program is stable.
166 You must also make sure this library routine is available:
169 @item void *memset(void *, int, int)
171 This is the standard library function @code{memset} that sets an area of
172 memory to a known value. If you have one of the free versions of
173 @code{libc.a}, @code{memset} can be found there; otherwise, you must
174 either obtain it from your hardware manufacturer, or write your own.
177 If you do not use the GNU C compiler, you may need other standard
178 library subroutines as well; this will vary from one stub to another,
179 but in general the stubs are likely to use any of the common library
180 subroutines which @code{gcc} generates as inline code.
184 @subsubsection Putting it all together
186 @cindex remote serial debugging summary
187 In summary, when your program is ready to debug, you must follow these
192 Make sure you have the supporting low-level routines:
193 @code{getDebugChar}, @code{putDebugChar}, @code{flush_i_cache},
197 Insert these lines near the top of your program:
205 Compile and link together: your program, the _GDBN__ debugging stub for
206 your target architecture, and the supporting subroutines.
209 Make sure you have a serial connection between your target machine and
210 the _GDBN__ host, and identify the serial port used for this on the host.
213 Download your program to your target machine (or get it there by
214 whatever means the manufacturer provides), and start it.
217 To start remote debugging, run _GDBN__ on the host machine, and specify
218 as an executable file the program that is running in the remote machine.
219 This tells _GDBN__ how to find your program's symbols and the contents
222 Then establish communication using the @code{target remote} command.
223 Its argument is the name of the device you're using to control the
224 target machine. For example:
227 target remote /dev/ttyb
231 if the serial line is connected to the device named @file{/dev/ttyb}.
233 @c this is from the old text, but it doesn't seem to make sense now that I've
234 @c seen an example... pesch 4sep1992
235 This will stop the remote machine if it is not already stopped.
240 Now you can use all the usual commands to examine and change data and to
241 step and continue the remote program.
243 To resume the remote program and stop debugging it, use the @code{detach}
247 @subsubsection Outline of the communication protocol
249 @cindex debugging stub, example
250 @cindex remote stub, example
251 @cindex stub example, remote debugging
252 The stub files provided with _GDBN__ implement the target side of the
253 communication protocol, and the _GDBN__ side is implemented in the
254 _GDBN__ source file @file{remote.c}. Normally, you can simply allow
255 these subroutines to communicate, and ignore the details. (If you're
256 implementing your own stub file, you can still ignore the details: start
257 with one of the existing stub files. @file{sparc-stub.c} is the best
258 organized, and therefore the easiest to read.)
260 However, there may be occasions when you need to know something about
261 the protocol---for example, if there is only one serial port to your
262 target machine, you might want your program to do something special if
263 it recognizes a packet meant for _GDBN__.
265 @cindex protocol, _GDBN__ remote serial
266 @cindex serial protocol, _GDBN__ remote
267 @cindex remote serial protocol
268 All _GDBN__ commands and responses (other than acknowledgements, which
269 are single characters) are sent as a packet which includes a
270 checksum. A packet is introduced with the character @samp{$}, and ends
271 with the character @samp{#} followed by a two-digit checksum:
274 $@var{packet info}#@var{checksum}
277 @cindex checksum, for _GDBN__ remote
279 @var{checksum} is computed as the modulo 256 sum of the @var{packet
282 When either the host or the target machine receives a packet, the first
283 response expected is an acknowledgement: a single character, either
284 @samp{+} (to indicate the package was received correctly) or @samp{-}
285 (to request retransmission).
287 The host (_GDBN__) sends commands, and the target (the debugging stub
288 incorporated in your program) sends data in response. The target also
289 sends data when your program stops.
291 Command packets are distinguished by their first character, which
292 identifies the kind of command.
294 These are the commands currently supported:
298 Requests the values of CPU registers.
301 Sets the values of CPU registers.
303 @item m@var{addr},@var{count}
304 Read @var{count} bytes at location @var{addr}.
306 @item M@var{addr},@var{count}:@dots{}
307 Write @var{count} bytes at location @var{addr}.
311 Resume execution at the current address (or at @var{addr} if supplied).
315 Step the target program for one instruction, from either the current
316 program counter or from @var{addr} if supplied.
319 Kill the target program.
322 Report the most recent signal. To allow you to take advantage of the
323 _GDBN__ signal handling commands, one of the functions of the debugging
324 stub is to report CPU traps as the corresponding POSIX signal values.
327 @kindex set remotedebug
328 @kindex show remotedebug
329 @cindex packets, reporting on stdout
330 @cindex serial connections, debugging
331 If you have trouble with the serial connection, you can use the command
332 @code{set remotedebug}. This makes _GDBN__ report on all packets sent
333 back and forth across the serial line to the remote machine. The
334 packet-debugging information is printed on the _GDBN__ standard output
335 stream. @code{set remotedebug off} turns it off, and @code{show
336 remotedebug} will show you its current state.
340 @node i960-Nindy Remote
341 @subsection _GDBN__ with a Remote i960 (Nindy)
345 @dfn{Nindy} is a ROM Monitor program for Intel 960 target systems. When
346 _GDBN__ is configured to control a remote Intel 960 using Nindy, you can
347 tell _GDBN__ how to connect to the 960 in several ways:
351 Through command line options specifying serial port, version of the
352 Nindy protocol, and communications speed;
355 By responding to a prompt on startup;
358 By using the @code{target} command at any point during your _GDBN__
359 session. @xref{Target Commands, ,Commands for Managing Targets}.
364 * Nindy Startup:: Startup with Nindy
365 * Nindy Options:: Options for Nindy
366 * Nindy reset:: Nindy Reset Command
370 @subsubsection Startup with Nindy
372 If you simply start @code{_GDBP__} without using any command-line
373 options, you are prompted for what serial port to use, @emph{before} you
374 reach the ordinary _GDBN__ prompt:
377 Attach /dev/ttyNN -- specify NN, or "quit" to quit:
381 Respond to the prompt with whatever suffix (after @samp{/dev/tty})
382 identifies the serial port you want to use. You can, if you choose,
383 simply start up with no Nindy connection by responding to the prompt
384 with an empty line. If you do this, and later wish to attach to Nindy,
385 use @code{target} (@pxref{Target Commands, ,Commands for Managing Targets}).
388 @subsubsection Options for Nindy
390 These are the startup options for beginning your _GDBN__ session with a
391 Nindy-960 board attached:
395 Specify the serial port name of a serial interface to be used to connect
396 to the target system. This option is only available when _GDBN__ is
397 configured for the Intel 960 target architecture. You may specify
398 @var{port} as any of: a full pathname (e.g. @samp{-r /dev/ttya}), a
399 device name in @file{/dev} (e.g. @samp{-r ttya}), or simply the unique
400 suffix for a specific @code{tty} (e.g. @samp{-r a}).
403 (An uppercase letter ``O'', not a zero.) Specify that _GDBN__ should use
404 the ``old'' Nindy monitor protocol to connect to the target system.
405 This option is only available when _GDBN__ is configured for the Intel 960
409 @emph{Warning:} if you specify @samp{-O}, but are actually trying to
410 connect to a target system that expects the newer protocol, the connection
411 will fail, appearing to be a speed mismatch. _GDBN__ will repeatedly
412 attempt to reconnect at several different line speeds. You can abort
413 this process with an interrupt.
417 Specify that _GDBN__ should first send a @code{BREAK} signal to the target
418 system, in an attempt to reset it, before connecting to a Nindy target.
421 @emph{Warning:} Many target systems do not have the hardware that this
422 requires; it only works with a few boards.
426 The standard @samp{-b} option controls the line speed used on the serial
431 @subsubsection Nindy Reset Command
436 For a Nindy target, this command sends a ``break'' to the remote target
437 system; this is only useful if the target has been equipped with a
438 circuit to perform a hard reset (or some other interesting action) when
446 @subsection _GDBN__ with a Remote EB29K
449 @cindex running 29K programs
451 To use _GDBN__ from a Unix system to run programs on AMD's EB29K
452 board in a PC, you must first connect a serial cable between the PC
453 and a serial port on the Unix system. In the following, we assume
454 you've hooked the cable between the PC's @file{COM1} port and
455 @file{/dev/ttya} on the Unix system.
458 * Comms (EB29K):: Communications Setup
459 * _GDBP__-EB29K:: EB29K cross-debugging
460 * Remote Log:: Remote Log
464 @subsubsection Communications Setup
466 The next step is to set up the PC's port, by doing something like the
467 following in DOS on the PC:
470 C:\> MODE com1:9600,n,8,1,none
474 This example---run on an MS DOS 4.0 system---sets the PC port to 9600
475 bps, no parity, eight data bits, one stop bit, and no ``retry'' action;
476 you must match the communications parameters when establishing the Unix
477 end of the connection as well.
478 @c FIXME: Who knows what this "no retry action" crud from the DOS manual may
479 @c mean? It's optional; leave it out? ---pesch@cygnus.com, 25feb91
481 To give control of the PC to the Unix side of the serial line, type
482 the following at the DOS console:
489 (Later, if you wish to return control to the DOS console, you can use
490 the command @code{CTTY con}---but you must send it over the device that
491 had control, in our example over the @file{COM1} serial line).
493 From the Unix host, use a communications program such as @code{tip} or
494 @code{cu} to communicate with the PC; for example,
497 cu -s 9600 -l /dev/ttya
501 The @code{cu} options shown specify, respectively, the linespeed and the
502 serial port to use. If you use @code{tip} instead, your command line
503 may look something like the following:
510 Your system may define a different name where our example uses
511 @file{/dev/ttya} as the argument to @code{tip}. The communications
512 parameters, including which port to use, are associated with the
513 @code{tip} argument in the ``remote'' descriptions file---normally the
514 system table @file{/etc/remote}.
515 @c FIXME: What if anything needs doing to match the "n,8,1,none" part of
516 @c the DOS side's comms setup? cu can support -o (odd
517 @c parity), -e (even parity)---apparently no settings for no parity or
518 @c for character size. Taken from stty maybe...? John points out tip
519 @c can set these as internal variables, eg ~s parity=none; man stty
520 @c suggests that it *might* work to stty these options with stdin or
521 @c stdout redirected... ---pesch@cygnus.com, 25feb91
524 Using the @code{tip} or @code{cu} connection, change the DOS working
525 directory to the directory containing a copy of your 29K program, then
526 start the PC program @code{EBMON} (an EB29K control program supplied
527 with your board by AMD). You should see an initial display from
528 @code{EBMON} similar to the one that follows, ending with the
529 @code{EBMON} prompt @samp{#}---
534 G:\> CD \usr\joe\work29k
536 G:\USR\JOE\WORK29K> EBMON
537 Am29000 PC Coprocessor Board Monitor, version 3.0-18
538 Copyright 1990 Advanced Micro Devices, Inc.
539 Written by Gibbons and Associates, Inc.
541 Enter '?' or 'H' for help
543 PC Coprocessor Type = EB29K
545 Memory Base = 0xd0000
547 Data Memory Size = 2048KB
548 Available I-RAM Range = 0x8000 to 0x1fffff
549 Available D-RAM Range = 0x80002000 to 0x801fffff
552 Register Stack Size = 0x800
553 Memory Stack Size = 0x1800
556 Am29027 Available = No
557 Byte Write Available = Yes
562 Then exit the @code{cu} or @code{tip} program (done in the example by
563 typing @code{~.} at the @code{EBMON} prompt). @code{EBMON} will keep
564 running, ready for _GDBN__ to take over.
566 For this example, we've assumed what is probably the most convenient
567 way to make sure the same 29K program is on both the PC and the Unix
568 system: a PC/NFS connection that establishes ``drive @code{G:}'' on the
569 PC as a file system on the Unix host. If you do not have PC/NFS or
570 something similar connecting the two systems, you must arrange some
571 other way---perhaps floppy-disk transfer---of getting the 29K program
572 from the Unix system to the PC; _GDBN__ will @emph{not} download it over the
576 @subsubsection EB29K cross-debugging
578 Finally, @code{cd} to the directory containing an image of your 29K
579 program on the Unix system, and start _GDBN__---specifying as argument the
580 name of your 29K program:
587 Now you can use the @code{target} command:
590 target amd-eb /dev/ttya 9600 MYFOO
591 @c FIXME: test above 'target amd-eb' as spelled, with caps! caps are meant to
592 @c emphasize that this is the name as seen by DOS (since I think DOS is
593 @c single-minded about case of letters). ---pesch@cygnus.com, 25feb91
597 In this example, we've assumed your program is in a file called
598 @file{myfoo}. Note that the filename given as the last argument to
599 @code{target amd-eb} should be the name of the program as it appears to DOS.
600 In our example this is simply @code{MYFOO}, but in general it can include
601 a DOS path, and depending on your transfer mechanism may not resemble
602 the name on the Unix side.
604 At this point, you can set any breakpoints you wish; when you are ready
605 to see your program run on the 29K board, use the _GDBN__ command
608 To stop debugging the remote program, use the _GDBN__ @code{detach}
611 To return control of the PC to its console, use @code{tip} or @code{cu}
612 once again, after your _GDBN__ session has concluded, to attach to
613 @code{EBMON}. You can then type the command @code{q} to shut down
614 @code{EBMON}, returning control to the DOS command-line interpreter.
615 Type @code{CTTY con} to return command input to the main DOS console,
616 and type @kbd{~.} to leave @code{tip} or @code{cu}.
619 @subsubsection Remote Log
621 @cindex log file for EB29K
623 The @code{target amd-eb} command creates a file @file{eb.log} in the
624 current working directory, to help debug problems with the connection.
625 @file{eb.log} records all the output from @code{EBMON}, including echoes
626 of the commands sent to it. Running @samp{tail -f} on this file in
627 another window often helps to understand trouble with @code{EBMON}, or
628 unexpected events on the PC side of the connection.
631 @subsection _GDBN__ and the UDI 29K protocol
633 If your 29K development system supports the UDI (``Universal Debug
634 Interface'') protocol, using _GDBN__ is almost transparent. UDI is a
635 TCP/IP based protocol. On some 29K development systens that do not
636 support TCP/IP directly, however, the manufacturer supplies an interface
637 adapter daemon, which translates UDI to whatever communications
638 interface---typically a serial port---is available.
640 Please see the manufacturer's documentation for your 29K system for how
641 to set up the UDI connection for your hardware.
643 Once the UDI connection is established, use @samp{target udi} from _GDBN__
644 to start using it. All the usual facilities of _GDBN__ are immediately
645 available: use @code{load} to get your program to the board,
646 @code{breakpoint} to say where to stop, @code{run} to start the program,
652 @subsection _GDBN__ with a Tandem ST2000
654 To connect your ST2000 to the host system, see the manufacturer's
655 manual. Once the ST2000 is physically attached, you can run
658 target st2000 @var{dev} @var{speed}
662 to establish it as your debugging environment.
664 The @code{load} and @code{attach} commands are @emph{not} defined for
665 this target; you must load your program into the ST2000 as you normally
666 would for standalone operation. _GDBN__ will read debugging information
667 (such as symbols) from a separate, debugging version of the program
668 available on your host computer.
669 @c FIXME!! This is terribly vague; what little content is here is
670 @c basically hearsay.
672 @cindex ST2000 auxiliary commands
673 These auxiliary _GDBN__ commands are available to help you with the ST2000
677 @item st2000 @var{command}
678 @kindex st2000 @var{cmd}
679 @cindex STDBUG commands (ST2000)
680 @cindex commands to STDBUG (ST2000)
681 Send a @var{command} to the STDBUG monitor. See the manufacturer's
682 manual for available commands.
685 @cindex connect (to STDBUG)
686 Connect the controlling terminal to the STDBUG command monitor. When
687 you are done interacting with STDBUG, typing either of two character
688 sequences will get you back to the _GDBN__ command prompt:
689 @kbd{@key{RET}~.} (Return, followed by tilde and period) or
690 @kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D).
696 @subsection _GDBN__ and VxWorks
699 _GDBN__ enables developers to spawn and debug tasks running on networked
700 VxWorks targets from a Unix host. Already-running tasks spawned from
701 the VxWorks shell can also be debugged. _GDBN__ uses code that runs on
702 both the UNIX host and on the VxWorks target. The program
703 @code{_GDBP__} is installed and executed on the UNIX host.
705 The following information on connecting to VxWorks was current when
706 this manual was produced; newer releases of VxWorks may use revised
709 The remote debugging interface (RDB) routines are installed and executed
710 on the VxWorks target. These routines are included in the VxWorks library
711 @file{rdb.a} and are incorporated into the system image when source-level
712 debugging is enabled in the VxWorks configuration.
715 If you wish, you can define @code{INCLUDE_RDB} in the VxWorks
716 configuration file @file{configAll.h} to include the RDB interface
717 routines and spawn the source debugging task @code{tRdbTask} when
718 VxWorks is booted. For more information on configuring and remaking
720 VxWorks, see the manufacturer's manual.
723 VxWorks, see the @cite{VxWorks Programmer's Guide}.
726 Once you have included the RDB interface in your VxWorks system image
727 and set your Unix execution search path to find _GDBN__, you are ready
728 to run _GDBN__. From your UNIX host, type:
734 _GDBN__ will come up showing the prompt:
741 * VxWorks connection:: Connecting to VxWorks
742 * VxWorks download:: VxWorks Download
743 * VxWorks attach:: Running Tasks
746 @node VxWorks connection
747 @subsubsection Connecting to VxWorks
749 The _GDBN__ command @code{target} lets you connect to a VxWorks target on the
750 network. To connect to a target whose host name is ``@code{tt}'', type:
753 (_GDBP__) target vxworks tt
756 _GDBN__ will display a message similar to the following:
759 Attaching remote machine across net... Success!
762 _GDBN__ will then attempt to read the symbol tables of any object modules
763 loaded into the VxWorks target since it was last booted. _GDBN__ locates
764 these files by searching the directories listed in the command search
765 path (@pxref{Environment, ,Your Program's Environment}); if it fails
766 to find an object file, it will display a message such as:
769 prog.o: No such file or directory.
772 This will cause the @code{target} command to abort. When this happens,
773 you should add the appropriate directory to the search path, with the
774 _GDBN__ command @code{path}, and execute the @code{target} command
777 @node VxWorks download
778 @subsubsection VxWorks Download
780 @cindex download to VxWorks
781 If you have connected to the VxWorks target and you want to debug an
782 object that has not yet been loaded, you can use the _GDBN__ @code{load}
783 command to download a file from UNIX to VxWorks incrementally. The
784 object file given as an argument to the @code{load} command is actually
785 opened twice: first by the VxWorks target in order to download the code,
786 then by _GDBN__ in order to read the symbol table. This can lead to
787 problems if the current working directories on the two systems differ.
788 It is simplest to set the working directory on both systems to the
789 directory in which the object file resides, and then to reference the
790 file by its name, without any path. Thus, to load a program
791 @file{prog.o}, residing in @file{wherever/vw/demo/rdb}, on VxWorks type:
794 -> cd "wherever/vw/demo/rdb"
800 (_GDBP__) cd wherever/vw/demo/rdb
801 (_GDBP__) load prog.o
804 _GDBN__ will display a response similar to the following:
807 Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
810 You can also use the @code{load} command to reload an object module
811 after editing and recompiling the corresponding source file. Note that
812 this will cause _GDBN__ to delete all currently-defined breakpoints,
813 auto-displays, and convenience variables, and to clear the value
814 history. (This is necessary in order to preserve the integrity of
815 debugger data structures that reference the target system's symbol
819 @subsubsection Running Tasks
821 @cindex running VxWorks tasks
822 You can also attach to an existing task using the @code{attach} command as
826 (_GDBP__) attach @var{task}
830 where @var{task} is the VxWorks hexadecimal task ID. The task can be running
831 or suspended when you attach to it. If running, it will be suspended at
832 the time of attachment.
836 @node Hitachi H8/300 Remote
837 @subsection _GDBN__ and the Hitachi H8/300
838 _GDBN__ needs to know these things to talk to your H8/300:
842 that you want to use @samp{target hms}, the remote debugging
843 interface for the H8/300 (this is the default when
844 GDB is configured specifically for the H8/300);
847 what serial device connects your host to your H8/300 (the first serial
848 device available on your host is the default);
851 @c this is only for Unix hosts, not currently of interest.
853 what speed to use over the serial device.
858 @cindex serial device for H8/300
860 @c only for Unix hosts
861 Use the special @code{gdb83} command @samp{device @var{port}} if you
862 need to explicitly set the serial device. The default @var{port} is the
863 first available port on your host. This is only necessary on Unix
864 hosts, where it is typically something like @file{/dev/ttya}.
867 @cindex serial line speed for H8/300
868 @code{gdb83} has another special command to set the communications speed
869 for the H8/300: @samp{speed @var{bps}}. This command also is only used
870 from Unix hosts; on DOS hosts, set the line speed as usual from outside
871 GDB with the DOS @kbd{mode} command (for instance, @w{@samp{mode
872 com2:9600,n,8,1,p}} for a 9600 bps connection).
875 _GDBN__ depends on an auxiliary terminate-and-stay-resident program
876 called @code{asynctsr} to communicate with the H8/300 development board
877 through a PC serial port. You must also use the DOS @code{mode} command
878 to set up the serial port on the DOS side.
880 The following sample session illustrates the steps needed to start a
881 program under _GDBN__ control on your H8/300. The example uses a sample
882 H8/300 program called @file{t.x}.
884 First hook up your H8/300 development board. In this example, we use a
885 board attached to serial port @code{COM2}; if you use a different serial
886 port, substitute its name in the argument of the @code{mode} command.
887 When you call @code{asynctsr}, the auxiliary comms program used by the
888 degugger, you give it just the numeric part of the serial port's name;
889 for example, @samp{asyncstr 2} below runs @code{asyncstr} on
893 (eg-C:\H8300\TEST) mode com2:9600,n,8,1,p
895 Resident portion of MODE loaded
897 COM2: 9600, n, 8, 1, p
899 (eg-C:\H8300\TEST) asynctsr 2
903 @emph{Warning:} We have noticed a bug in PC-NFS that conflicts with
904 @code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to
905 disable it, or even boot without it, to use @code{asynctsr} to control
909 Now that serial communications are set up, and the H8/300 is connected,
910 you can start up _GDBN__. Call @code{_GDBP__} with the name of your
911 program as the argument. @code{_GDBP__} prompts you, as usual, with the
912 prompt @samp{(_GDBP__)}. Use two special commands to begin your debugging
913 session: @samp{target hms} to specify cross-debugging to the Hitachi board,
914 and the @code{load} command to download your program to the board.
915 @code{load} displays the names of the
916 program's sections, and a @samp{*} for each 2K of data downloaded. (If
917 you want to refresh _GDBN__ data on symbols or on the executable file
918 without downloading, use the _GDBN__ commands @code{file} or
919 @code{symbol-file}. These commands, and @code{load} itself, are
920 described in @ref{Files,,Commands to Specify Files}.)
923 (eg-C:\H8300\TEST) _GDBP__ t.x
924 GDB is free software and you are welcome to distribute copies
925 of it under certain conditions; type "show copying" to see
927 There is absolutely no warranty for GDB; type "show warranty"
929 GDB _GDB_VN__, Copyright 1992 Free Software Foundation, Inc...
931 Connected to remote H8/300 HMS system.
933 .text : 0x8000 .. 0xabde ***********
934 .data : 0xabde .. 0xad30 *
935 .stack : 0xf000 .. 0xf014 *
938 At this point, you're ready to run or debug your program. From here on,
939 you can use all the usual _GDBN__ commands. The @code{break} command
940 sets breakpoints; the @code{run} command starts your program;
941 @code{print} or @code{x} display data; the @code{continue} command
942 resumes execution after stopping at a breakpoint. You can use the
943 @code{help} command at any time to find out more about _GDBN__ commands.
945 Remember, however, that @emph{operating system} facilities aren't
946 available on your H8/300; for example, if your program hangs, you can't
947 send an interrupt---but you can press the @sc{reset} switch!
949 Use the @sc{reset} button on the H8/300 board
952 to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has
953 no way to pass an interrupt signal to the H8/300); and
956 to return to the _GDBN__ command prompt after your program finishes
957 normally. The communications protocol provides no other way for _GDBN__
958 to detect program completion.
961 In either case, _GDBN__ will see the effect of a @sc{reset} on the
962 H8/300 board as a ``normal exit'' of your program.