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 @kindex 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 Write this function to install @var{exception_address} in the exception
170 handling tables. You need to do this because the stub does not have any
171 way of knowing what the exception handling tables on your target system
172 are like (for example, the processor's table might be in @sc{rom},
173 containing entries which point to a table in @sc{ram}).
174 @var{exception_number} is the exception number which should be changed;
175 its meaning is architecture-dependent (for example, different numbers
176 might represent divide by zero, misaligned access, etc). When this
177 exception occurs, control should be transferred directly to
178 @var{exception_address}, and the processor state (stack, registers,
179 etc.) should be just as it is when a processor exception occurs. So if
180 you want to use a jump instruction to reach @var{exception_address}, it
181 should be a simple jump, not a jump to subroutine.
183 @c For the 386, doesn't the interrupt gate contain a privilege level?
184 @c If so, what should it be set to? I suspect the answer is the
185 @c privilege level in effect at the time that exceptionHandler is
186 @c called, but I'm not sure. FIXME.
187 For the 386, @var{exception_address} should be installed as an interrupt
188 gate so that interrupts are masked while the handler runs. The
189 @sc{sparc} and 68k stubs are able to mask interrupts themself without
190 help from @code{exceptionHandler}.
192 @item void flush_i_cache()
193 @kindex flush_i_cache
194 Write this subroutine to flush the instruction cache, if any, on your
195 target machine. If there is no instruction cache, this subroutine may
198 On target machines that have instruction caches, @value{GDBN} requires this
199 function to make certain that the state of your program is stable.
203 You must also make sure this library routine is available:
206 @item void *memset(void *, int, int)
208 This is the standard library function @code{memset} that sets an area of
209 memory to a known value. If you have one of the free versions of
210 @code{libc.a}, @code{memset} can be found there; otherwise, you must
211 either obtain it from your hardware manufacturer, or write your own.
214 If you do not use the GNU C compiler, you may need other standard
215 library subroutines as well; this will vary from one stub to another,
216 but in general the stubs are likely to use any of the common library
217 subroutines which @code{gcc} generates as inline code.
221 @subsubsection Putting it all together
223 @cindex remote serial debugging summary
224 In summary, when your program is ready to debug, you must follow these
229 Make sure you have the supporting low-level routines
230 (@pxref{Bootstrapping}):
232 @code{getDebugChar}, @code{putDebugChar},
233 @code{flush_i_cache}, @code{memset}, @code{exceptionHandler}.
237 Insert these lines near the top of your program:
245 For the 680x0 stub only, you need to provide a variable called
246 @code{exceptionHook}. Normally you just use
249 void (*exceptionHook)() = 0;
252 but if before calling @code{set_debug_traps}, you set it to point to a
253 function in your program, that function is called when
254 @code{@value{GDBN}} continues after stopping on a trap (for example, bus
255 error). The function indicated by @code{exceptionHook} is called with
256 one parameter: an @code{int} which is the exception number.
259 Compile and link together: your program, the @value{GDBN} debugging stub for
260 your target architecture, and the supporting subroutines.
263 Make sure you have a serial connection between your target machine and
264 the @value{GDBN} host, and identify the serial port used for this on the host.
267 @c The "remote" target now provides a `load' command, so we should
268 @c document that. FIXME.
269 Download your program to your target machine (or get it there by
270 whatever means the manufacturer provides), and start it.
273 To start remote debugging, run @value{GDBN} on the host machine, and specify
274 as an executable file the program that is running in the remote machine.
275 This tells @value{GDBN} how to find your program's symbols and the contents
278 @cindex serial line, @code{target remote}
279 Then establish communication using the @code{target remote} command.
280 Its argument specifies how to communicate with the target
281 machine---either via a devicename attached to a direct serial line, or a
282 TCP port (usually to a terminal server which in turn has a serial line
283 to the target). For example, to use a serial line connected to the
284 device named @file{/dev/ttyb}:
287 target remote /dev/ttyb
290 @cindex TCP port, @code{target remote}
291 To use a TCP connection, use an argument of the form
292 @code{@var{host}:port}. For example, to connect to port 2828 on a
293 terminal server named @code{manyfarms}:
296 target remote manyfarms:2828
300 Now you can use all the usual commands to examine and change data and to
301 step and continue the remote program.
303 To resume the remote program and stop debugging it, use the @code{detach}
306 @cindex interrupting remote programs
307 @cindex remote programs, interrupting
308 Whenever @value{GDBN} is waiting for the remote program, if you type the
309 interrupt character (often @key{C-C}), @value{GDBN} attempts to stop the
310 program. This may or may not succeed, depending in part on the hardware
311 and the serial drivers the remote system uses. If you type the
312 interrupt character once again, @value{GDBN} displays this prompt:
315 Interrupted while waiting for the program.
316 Give up (and stop debugging it)? (y or n)
319 If you type @kbd{y}, @value{GDBN} abandons the remote debugging session.
320 (If you decide you want to try again later, you can use @samp{target
321 remote} again to connect once more.) If you type @kbd{n}, @value{GDBN}
322 goes back to waiting.
325 @subsubsection Outline of the communication protocol
327 @cindex debugging stub, example
328 @cindex remote stub, example
329 @cindex stub example, remote debugging
330 The stub files provided with @value{GDBN} implement the target side of the
331 communication protocol, and the @value{GDBN} side is implemented in the
332 @value{GDBN} source file @file{remote.c}. Normally, you can simply allow
333 these subroutines to communicate, and ignore the details. (If you're
334 implementing your own stub file, you can still ignore the details: start
335 with one of the existing stub files. @file{sparc-stub.c} is the best
336 organized, and therefore the easiest to read.)
338 However, there may be occasions when you need to know something about
339 the protocol---for example, if there is only one serial port to your
340 target machine, you might want your program to do something special if
341 it recognizes a packet meant for @value{GDBN}.
343 @cindex protocol, @value{GDBN} remote serial
344 @cindex serial protocol, @value{GDBN} remote
345 @cindex remote serial protocol
346 All @value{GDBN} commands and responses (other than acknowledgements, which
347 are single characters) are sent as a packet which includes a
348 checksum. A packet is introduced with the character @samp{$}, and ends
349 with the character @samp{#} followed by a two-digit checksum:
352 $@var{packet info}#@var{checksum}
355 @cindex checksum, for @value{GDBN} remote
357 @var{checksum} is computed as the modulo 256 sum of the @var{packet
360 When either the host or the target machine receives a packet, the first
361 response expected is an acknowledgement: a single character, either
362 @samp{+} (to indicate the package was received correctly) or @samp{-}
363 (to request retransmission).
365 The host (@value{GDBN}) sends commands, and the target (the debugging stub
366 incorporated in your program) sends data in response. The target also
367 sends data when your program stops.
369 Command packets are distinguished by their first character, which
370 identifies the kind of command.
372 These are the commands currently supported:
376 Requests the values of CPU registers.
379 Sets the values of CPU registers.
381 @item m@var{addr},@var{count}
382 Read @var{count} bytes at location @var{addr}.
384 @item M@var{addr},@var{count}:@dots{}
385 Write @var{count} bytes at location @var{addr}.
389 Resume execution at the current address (or at @var{addr} if supplied).
393 Step the target program for one instruction, from either the current
394 program counter or from @var{addr} if supplied.
397 Kill the target program.
400 Report the most recent signal. To allow you to take advantage of the
401 @value{GDBN} signal handling commands, one of the functions of the debugging
402 stub is to report CPU traps as the corresponding POSIX signal values.
405 @kindex set remotedebug
406 @kindex show remotedebug
407 @cindex packets, reporting on stdout
408 @cindex serial connections, debugging
409 If you have trouble with the serial connection, you can use the command
410 @code{set remotedebug}. This makes @value{GDBN} report on all packets sent
411 back and forth across the serial line to the remote machine. The
412 packet-debugging information is printed on the @value{GDBN} standard output
413 stream. @code{set remotedebug off} turns it off, and @code{show
414 remotedebug} will show you its current state.
418 @subsubsection Using the @code{gdbserver} program
421 @cindex remote connection without stubs
422 @code{gdbserver} is a control program for Unix-like systems, which
423 allows you to connect your program with a remote @value{GDBN} via
424 @code{target remote}---but without linking in the usual debugging stub.
426 @code{gdbserver} is not a complete replacement for the debugging stubs,
427 because it requires essentially the same operating-system facilities
428 that @value{GDBN} itself does. In fact, a system that can run
429 @code{gdbserver} to connect to a remote @value{GDBN} could also run
430 @var{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless,
431 because it is a much smaller program than @value{GDBN} itself. It is
432 also easier to port than all of @var{GDBN}, so you may be able to get
433 started more quickly on a new system by using @code{gdbserver}.
435 @value{GDBN} and @code{gdbserver} communicate via either a serial line
436 or a TCP connection, using the standard @value{GDBN} remote serial
441 you need to have a copy of the program you want to debug.
442 @code{gdbserver} does not need your program's symbol table, so you can
443 strip the program if necessary to save space. @value{GDBN} on the host
444 system does all the symbol handling.
446 To use the server, you must tell it how to communicate with @value{GDB};
447 the name of your program; and the arguments for your program. The
451 target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ]
454 @var{comm} is either a device name (to use a serial line) or a TCP
455 hostname and portnumber. For example, to debug emacs with the argument
456 @samp{foo.txt} and communicate with @value{GDBN} over the serial port
460 target> gdbserver /dev/com1 emacs foo.txt
463 @code{gdbserver} waits passively for the host @value{GDBN} to communicate
466 To use a TCP connection instead of a serial line:
469 target> gdbserver host:2345 emacs foo.txt
472 The only difference from the previous example is the first argument,
473 specifying that you are communicating with the host @value{GDBN} via
474 TCP. The @samp{host:2345} argument means that @code{gdbserver} is to
475 expect a TCP connection from machine @samp{host} to local TCP port 2345.
476 (Currently, the @samp{host} part is ignored.) You can choose any number
477 you want for the port number as long as it does not conflict with any
478 TCP ports already in use on the target system.@footnote{If you choose a
479 port number that conflicts with another service, @code{gdbserver} prints
480 an error message and exits.} You must use the same port number with the
481 host @value{GDBN} @code{target remote} command.
484 you need an unstripped copy of your program, since
485 @value{GDBN} needs symbols and debugging information. Start up
486 @value{GDBN} as usual, using the name of the local copy of your program
487 as the first argument. (You may also need the
488 @samp{--baud} option if the serial line is running at anything other than 9600 bps.)
489 After that, use @code{target remote} to establish communications with @code{gdbserver}. Its argument is either
490 a device name (usually a serial device, like @file{/dev/ttyb}), or a TCP
491 port descriptof in the form @code{@var{host}:@var{PORT}}. For example:
494 (@value{GDBP}) target remote /dev/ttyb
498 communicates with the server via serial line @file{/dev/ttyb}, and
501 (@value{GDBP}) target remote the-target:2345
505 communicates via a TCP connection to port 2345 on host @file{the-target}.
506 For TCP connections, you must start up @code{gdbserver} prior to using
507 the @code{target remote} command. Otherwise you may get an error whose
508 text depends on the host system, but which usually looks something like
509 @samp{Connection refused}.
516 @node i960-Nindy Remote
517 @subsection @value{GDBN} with a remote i960 (Nindy)
521 @dfn{Nindy} is a ROM Monitor program for Intel 960 target systems. When
522 @value{GDBN} is configured to control a remote Intel 960 using Nindy, you can
523 tell @value{GDBN} how to connect to the 960 in several ways:
527 Through command line options specifying serial port, version of the
528 Nindy protocol, and communications speed;
531 By responding to a prompt on startup;
534 By using the @code{target} command at any point during your @value{GDBN}
535 session. @xref{Target Commands, ,Commands for managing targets}.
540 * Nindy Startup:: Startup with Nindy
541 * Nindy Options:: Options for Nindy
542 * Nindy Reset:: Nindy reset command
546 @subsubsection Startup with Nindy
548 If you simply start @code{@value{GDBP}} without using any command-line
549 options, you are prompted for what serial port to use, @emph{before} you
550 reach the ordinary @value{GDBN} prompt:
553 Attach /dev/ttyNN -- specify NN, or "quit" to quit:
557 Respond to the prompt with whatever suffix (after @samp{/dev/tty})
558 identifies the serial port you want to use. You can, if you choose,
559 simply start up with no Nindy connection by responding to the prompt
560 with an empty line. If you do this and later wish to attach to Nindy,
561 use @code{target} (@pxref{Target Commands, ,Commands for managing targets}).
564 @subsubsection Options for Nindy
566 These are the startup options for beginning your @value{GDBN} session with a
567 Nindy-960 board attached:
571 Specify the serial port name of a serial interface to be used to connect
572 to the target system. This option is only available when @value{GDBN} is
573 configured for the Intel 960 target architecture. You may specify
574 @var{port} as any of: a full pathname (e.g. @samp{-r /dev/ttya}), a
575 device name in @file{/dev} (e.g. @samp{-r ttya}), or simply the unique
576 suffix for a specific @code{tty} (e.g. @samp{-r a}).
579 (An uppercase letter ``O'', not a zero.) Specify that @value{GDBN} should use
580 the ``old'' Nindy monitor protocol to connect to the target system.
581 This option is only available when @value{GDBN} is configured for the Intel 960
585 @emph{Warning:} if you specify @samp{-O}, but are actually trying to
586 connect to a target system that expects the newer protocol, the connection
587 fails, appearing to be a speed mismatch. @value{GDBN} repeatedly
588 attempts to reconnect at several different line speeds. You can abort
589 this process with an interrupt.
593 Specify that @value{GDBN} should first send a @code{BREAK} signal to the target
594 system, in an attempt to reset it, before connecting to a Nindy target.
597 @emph{Warning:} Many target systems do not have the hardware that this
598 requires; it only works with a few boards.
602 The standard @samp{-b} option controls the line speed used on the serial
607 @subsubsection Nindy reset command
612 For a Nindy target, this command sends a ``break'' to the remote target
613 system; this is only useful if the target has been equipped with a
614 circuit to perform a hard reset (or some other interesting action) when
622 @subsection @value{GDBN} and the UDI protocol for AMD29K
625 @cindex AMD29K via UDI
626 @value{GDBN} supports AMD's UDI (``Universal Debugger Interface'')
627 protocol for debugging the a29k processor family. To use this
628 configuration with AMD targets running the MiniMON monitor, you need the
629 program @code{MONTIP}, available from AMD at no charge. You can also
630 use @value{GDBN} with the UDI conformant a29k simulator program
631 @code{ISSTIP}, also available from AMD.
634 @item target udi @var{keyword}
636 Select the UDI interface to a remote a29k board or simulator, where
637 @var{keyword} is an entry in the AMD configuration file @file{udi_soc}.
638 This file contains keyword entries which specify parameters used to
639 connect to a29k targets. If the @file{udi_soc} file is not in your
640 working directory, you must set the environment variable @samp{UDICONF}
645 @subsection @value{GDBN} and the EBMON protocol for AMD29K
648 @cindex running 29K programs
650 AMD distributes a 29K development board meant to fit in a PC, together
651 with a DOS-hosted monitor program called @code{EBMON}. As a shorthand
652 term, this development system is called the ``EB29K''. To use
653 @value{GDBN} from a Unix system to run programs on the EB29K board, you
654 must first connect a serial cable between the PC (which hosts the EB29K
655 board) and a serial port on the Unix system. In the following, we
656 assume you've hooked the cable between the PC's @file{COM1} port and
657 @file{/dev/ttya} on the Unix system.
660 * Comms (EB29K):: Communications setup
661 * gdb-EB29K:: EB29K cross-debugging
662 * Remote Log:: Remote log
666 @subsubsection Communications setup
668 The next step is to set up the PC's port, by doing something like this
672 C:\> MODE com1:9600,n,8,1,none
676 This example---run on an MS DOS 4.0 system---sets the PC port to 9600
677 bps, no parity, eight data bits, one stop bit, and no ``retry'' action;
678 you must match the communications parameters when establishing the Unix
679 end of the connection as well.
680 @c FIXME: Who knows what this "no retry action" crud from the DOS manual may
681 @c mean? It's optional; leave it out? ---pesch@cygnus.com, 25feb91
683 To give control of the PC to the Unix side of the serial line, type
684 the following at the DOS console:
691 (Later, if you wish to return control to the DOS console, you can use
692 the command @code{CTTY con}---but you must send it over the device that
693 had control, in our example over the @file{COM1} serial line).
695 From the Unix host, use a communications program such as @code{tip} or
696 @code{cu} to communicate with the PC; for example,
699 cu -s 9600 -l /dev/ttya
703 The @code{cu} options shown specify, respectively, the linespeed and the
704 serial port to use. If you use @code{tip} instead, your command line
705 may look something like the following:
712 Your system may require a different name where we show
713 @file{/dev/ttya} as the argument to @code{tip}. The communications
714 parameters, including which port to use, are associated with the
715 @code{tip} argument in the ``remote'' descriptions file---normally the
716 system table @file{/etc/remote}.
717 @c FIXME: What if anything needs doing to match the "n,8,1,none" part of
718 @c the DOS side's comms setup? cu can support -o (odd
719 @c parity), -e (even parity)---apparently no settings for no parity or
720 @c for character size. Taken from stty maybe...? John points out tip
721 @c can set these as internal variables, eg ~s parity=none; man stty
722 @c suggests that it *might* work to stty these options with stdin or
723 @c stdout redirected... ---pesch@cygnus.com, 25feb91
726 Using the @code{tip} or @code{cu} connection, change the DOS working
727 directory to the directory containing a copy of your 29K program, then
728 start the PC program @code{EBMON} (an EB29K control program supplied
729 with your board by AMD). You should see an initial display from
730 @code{EBMON} similar to the one that follows, ending with the
731 @code{EBMON} prompt @samp{#}---
736 G:\> CD \usr\joe\work29k
738 G:\USR\JOE\WORK29K> EBMON
739 Am29000 PC Coprocessor Board Monitor, version 3.0-18
740 Copyright 1990 Advanced Micro Devices, Inc.
741 Written by Gibbons and Associates, Inc.
743 Enter '?' or 'H' for help
745 PC Coprocessor Type = EB29K
747 Memory Base = 0xd0000
749 Data Memory Size = 2048KB
750 Available I-RAM Range = 0x8000 to 0x1fffff
751 Available D-RAM Range = 0x80002000 to 0x801fffff
754 Register Stack Size = 0x800
755 Memory Stack Size = 0x1800
758 Am29027 Available = No
759 Byte Write Available = Yes
764 Then exit the @code{cu} or @code{tip} program (done in the example by
765 typing @code{~.} at the @code{EBMON} prompt). @code{EBMON} will keep
766 running, ready for @value{GDBN} to take over.
768 For this example, we've assumed what is probably the most convenient
769 way to make sure the same 29K program is on both the PC and the Unix
770 system: a PC/NFS connection that establishes ``drive @code{G:}'' on the
771 PC as a file system on the Unix host. If you do not have PC/NFS or
772 something similar connecting the two systems, you must arrange some
773 other way---perhaps floppy-disk transfer---of getting the 29K program
774 from the Unix system to the PC; @value{GDBN} will @emph{not} download it over the
778 @subsubsection EB29K cross-debugging
780 Finally, @code{cd} to the directory containing an image of your 29K
781 program on the Unix system, and start @value{GDBN}---specifying as argument the
782 name of your 29K program:
789 Now you can use the @code{target} command:
792 target amd-eb /dev/ttya 9600 MYFOO
793 @c FIXME: test above 'target amd-eb' as spelled, with caps! caps are meant to
794 @c emphasize that this is the name as seen by DOS (since I think DOS is
795 @c single-minded about case of letters). ---pesch@cygnus.com, 25feb91
799 In this example, we've assumed your program is in a file called
800 @file{myfoo}. Note that the filename given as the last argument to
801 @code{target amd-eb} should be the name of the program as it appears to DOS.
802 In our example this is simply @code{MYFOO}, but in general it can include
803 a DOS path, and depending on your transfer mechanism may not resemble
804 the name on the Unix side.
806 At this point, you can set any breakpoints you wish; when you are ready
807 to see your program run on the 29K board, use the @value{GDBN} command
810 To stop debugging the remote program, use the @value{GDBN} @code{detach}
813 To return control of the PC to its console, use @code{tip} or @code{cu}
814 once again, after your @value{GDBN} session has concluded, to attach to
815 @code{EBMON}. You can then type the command @code{q} to shut down
816 @code{EBMON}, returning control to the DOS command-line interpreter.
817 Type @code{CTTY con} to return command input to the main DOS console,
818 and type @kbd{~.} to leave @code{tip} or @code{cu}.
821 @subsubsection Remote log
823 @cindex log file for EB29K
825 The @code{target amd-eb} command creates a file @file{eb.log} in the
826 current working directory, to help debug problems with the connection.
827 @file{eb.log} records all the output from @code{EBMON}, including echoes
828 of the commands sent to it. Running @samp{tail -f} on this file in
829 another window often helps to understand trouble with @code{EBMON}, or
830 unexpected events on the PC side of the connection.
836 @subsection @value{GDBN} with a Tandem ST2000
838 To connect your ST2000 to the host system, see the manufacturer's
839 manual. Once the ST2000 is physically attached, you can run
842 target st2000 @var{dev} @var{speed}
846 to establish it as your debugging environment. @var{dev} is normally
847 the name of a serial device, such as @file{/dev/ttya}, connected to the
848 ST2000 via a serial line. You can instead specify @var{dev} as a TCP
849 connection (for example, to a serial line attached via a terminal
850 concentrator) using the syntax @code{@var{hostname}:@var{portnumber}}.
852 The @code{load} and @code{attach} commands are @emph{not} defined for
853 this target; you must load your program into the ST2000 as you normally
854 would for standalone operation. @value{GDBN} will read debugging information
855 (such as symbols) from a separate, debugging version of the program
856 available on your host computer.
857 @c FIXME!! This is terribly vague; what little content is here is
858 @c basically hearsay.
860 @cindex ST2000 auxiliary commands
861 These auxiliary @value{GDBN} commands are available to help you with the ST2000
865 @item st2000 @var{command}
866 @kindex st2000 @var{cmd}
867 @cindex STDBUG commands (ST2000)
868 @cindex commands to STDBUG (ST2000)
869 Send a @var{command} to the STDBUG monitor. See the manufacturer's
870 manual for available commands.
873 @cindex connect (to STDBUG)
874 Connect the controlling terminal to the STDBUG command monitor. When
875 you are done interacting with STDBUG, typing either of two character
876 sequences will get you back to the @value{GDBN} command prompt:
877 @kbd{@key{RET}~.} (Return, followed by tilde and period) or
878 @kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D).
884 @subsection @value{GDBN} and VxWorks
887 @value{GDBN} enables developers to spawn and debug tasks running on networked
888 VxWorks targets from a Unix host. Already-running tasks spawned from
889 the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on
890 both the UNIX host and on the VxWorks target. The program
891 @code{gdb} is installed and executed on the UNIX host. (It may be
892 installed with the name @code{vxgdb}, to distinguish it from a
893 @value{GDBN} for debugging programs on the host itself.)
895 The following information on connecting to VxWorks was current when
896 this manual was produced; newer releases of VxWorks may use revised
899 The remote debugging interface (RDB) routines are installed and executed
900 on the VxWorks target. These routines are included in the VxWorks library
901 @file{rdb.a} and are incorporated into the system image when source-level
902 debugging is enabled in the VxWorks configuration.
905 If you wish, you can define @code{INCLUDE_RDB} in the VxWorks
906 configuration file @file{configAll.h} to include the RDB interface
907 routines and spawn the source debugging task @code{tRdbTask} when
908 VxWorks is booted. For more information on configuring and remaking
909 VxWorks, see the manufacturer's manual.
910 @c VxWorks, see the @cite{VxWorks Programmer's Guide}.
912 Once you have included the RDB interface in your VxWorks system image
913 and set your Unix execution search path to find @value{GDBN}, you are ready
914 to run @value{GDBN}. From your UNIX host, run @code{gdb} (or
915 @code{vxgdb}, depending on your installation).
917 @value{GDBN} comes up showing the prompt:
924 * VxWorks Connection:: Connecting to VxWorks
925 * VxWorks Download:: VxWorks download
926 * VxWorks Attach:: Running tasks
929 @node VxWorks Connection
930 @subsubsection Connecting to VxWorks
932 The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the
933 network. To connect to a target whose host name is ``@code{tt}'', type:
936 (vxgdb) target vxworks tt
939 @value{GDBN} displays messages like these:
942 Attaching remote machine across net...
946 @value{GDBN} then attempts to read the symbol tables of any object modules
947 loaded into the VxWorks target since it was last booted. @value{GDBN} locates
948 these files by searching the directories listed in the command search
949 path (@pxref{Environment, ,Your program's environment}); if it fails
950 to find an object file, it displays a message such as:
953 prog.o: No such file or directory.
956 When this happens, add the appropriate directory to the search path with
957 the @value{GDBN} command @code{path}, and execute the @code{target}
960 @node VxWorks Download
961 @subsubsection VxWorks download
963 @cindex download to VxWorks
964 If you have connected to the VxWorks target and you want to debug an
965 object that has not yet been loaded, you can use the @value{GDBN}
966 @code{load} command to download a file from UNIX to VxWorks
967 incrementally. The object file given as an argument to the @code{load}
968 command is actually opened twice: first by the VxWorks target in order
969 to download the code, then by @value{GDBN} in order to read the symbol
970 table. This can lead to problems if the current working directories on
971 the two systems differ. If both systems have NFS mounted the same
972 filesystems, you can avoid these problems by using absolute paths.
973 Otherwise, it is simplest to set the working directory on both systems
974 to the directory in which the object file resides, and then to reference
975 the file by its name, without any path. For instance, a program
976 @file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks
977 and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this
978 program, type this on VxWorks:
981 -> cd "@var{vxpath}/vw/demo/rdb"
984 Then, in @value{GDBN}, type:
987 (vxgdb) cd @var{hostpath}/vw/demo/rdb
991 @value{GDBN} displays a response similar to this:
994 Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
997 You can also use the @code{load} command to reload an object module
998 after editing and recompiling the corresponding source file. Note that
999 this will cause @value{GDBN} to delete all currently-defined breakpoints,
1000 auto-displays, and convenience variables, and to clear the value
1001 history. (This is necessary in order to preserve the integrity of
1002 debugger data structures that reference the target system's symbol
1005 @node VxWorks Attach
1006 @subsubsection Running tasks
1008 @cindex running VxWorks tasks
1009 You can also attach to an existing task using the @code{attach} command as
1013 (vxgdb) attach @var{task}
1017 where @var{task} is the VxWorks hexadecimal task ID. The task can be running
1018 or suspended when you attach to it. If running, it will be suspended at
1019 the time of attachment.
1023 @node Hitachi Remote
1024 @subsection @value{GDBN} and Hitachi Microprocessors
1025 @value{GDBN} needs to know these things to talk to your
1026 Hitachi SH, H8/300, or H8/500:
1030 that you want to use @samp{target hms}, the remote debugging interface
1031 for Hitachi microprocessors (this is the default when GDB is configured
1032 specifically for the Hitachi SH, H8/300, or H8/500);
1035 what serial device connects your host to your Hitachi board (the first
1036 serial device available on your host is the default);
1039 @c this is only for Unix hosts, not currently of interest.
1041 what speed to use over the serial device.
1045 @ifclear H8EXCLUSIVE
1046 @c only for Unix hosts
1048 @cindex serial device, Hitachi micros
1049 Use the special @code{@value{GDBP}} command @samp{device @var{port}} if you
1050 need to explicitly set the serial device. The default @var{port} is the
1051 first available port on your host. This is only necessary on Unix
1052 hosts, where it is typically something like @file{/dev/ttya}.
1055 @cindex serial line speed, Hitachi micros
1056 @code{@value{GDBP}} has another special command to set the communications
1057 speed: @samp{speed @var{bps}}. This command also is only used from Unix
1058 hosts; on DOS hosts, set the line speed as usual from outside GDB with
1059 the DOS @kbd{mode} command (for instance, @w{@samp{mode
1060 com2:9600,n,8,1,p}} for a 9600 bps connection).
1062 The @samp{device} and @samp{speed} commands are available only when you
1063 use a Unix host to debug your Hitachi microprocessor programs. If you
1066 @value{GDBN} depends on an auxiliary terminate-and-stay-resident program
1067 called @code{asynctsr} to communicate with the development board
1068 through a PC serial port. You must also use the DOS @code{mode} command
1069 to set up the serial port on the DOS side.
1072 The following sample session illustrates the steps needed to start a
1073 program under @value{GDBN} control on an H8/300. The example uses a
1074 sample H8/300 program called @file{t.x}. The procedure is the same for
1075 the Hitachi SH and the H8/500.
1077 First hook up your development board. In this example, we use a
1078 board attached to serial port @code{COM2}; if you use a different serial
1079 port, substitute its name in the argument of the @code{mode} command.
1080 When you call @code{asynctsr}, the auxiliary comms program used by the
1081 degugger, you give it just the numeric part of the serial port's name;
1082 for example, @samp{asyncstr 2} below runs @code{asyncstr} on
1086 (eg-C:\H8300\TEST) mode com2:9600,n,8,1,p
1088 Resident portion of MODE loaded
1090 COM2: 9600, n, 8, 1, p
1092 (eg-C:\H8300\TEST) asynctsr 2
1096 @emph{Warning:} We have noticed a bug in PC-NFS that conflicts with
1097 @code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to
1098 disable it, or even boot without it, to use @code{asynctsr} to control
1099 your development board.
1103 Now that serial communications are set up, and the development board is
1104 connected, you can start up @value{GDBN}. Call @code{@value{GDBP}} with
1105 the name of your program as the argument. @code{@value{GDBP}} prompts
1106 you, as usual, with the prompt @samp{(@value{GDBP})}. Use two special
1107 commands to begin your debugging session: @samp{target hms} to specify
1108 cross-debugging to the Hitachi board, and the @code{load} command to
1109 download your program to the board. @code{load} displays the names of
1110 the program's sections, and a @samp{*} for each 2K of data downloaded.
1111 (If you want to refresh @value{GDBN} data on symbols or on the
1112 executable file without downloading, use the @value{GDBN} commands
1113 @code{file} or @code{symbol-file}. These commands, and @code{load}
1114 itself, are described in @ref{Files,,Commands to specify files}.)
1117 (eg-C:\H8300\TEST) @value{GDBP} t.x
1118 GDB is free software and you are welcome to distribute copies
1119 of it under certain conditions; type "show copying" to see
1121 There is absolutely no warranty for GDB; type "show warranty"
1123 GDB @value{GDBVN}, Copyright 1992 Free Software Foundation, Inc...
1125 Connected to remote H8/300 HMS system.
1127 .text : 0x8000 .. 0xabde ***********
1128 .data : 0xabde .. 0xad30 *
1129 .stack : 0xf000 .. 0xf014 *
1132 At this point, you're ready to run or debug your program. From here on,
1133 you can use all the usual @value{GDBN} commands. The @code{break} command
1134 sets breakpoints; the @code{run} command starts your program;
1135 @code{print} or @code{x} display data; the @code{continue} command
1136 resumes execution after stopping at a breakpoint. You can use the
1137 @code{help} command at any time to find out more about @value{GDBN} commands.
1139 Remember, however, that @emph{operating system} facilities aren't
1140 available on your development board; for example, if your program hangs,
1141 you can't send an interrupt---but you can press the @sc{reset} switch!
1143 Use the @sc{reset} button on the development board
1146 to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has
1147 no way to pass an interrupt signal to the development board); and
1150 to return to the @value{GDBN} command prompt after your program finishes
1151 normally. The communications protocol provides no other way for @value{GDBN}
1152 to detect program completion.
1155 In either case, @value{GDBN} will see the effect of a @sc{reset} on the
1156 development board as a ``normal exit'' of your program.
1162 @subsection @value{GDBN} and remote MIPS boards
1165 @value{GDBN} can use the MIPS remote debugging protocol to talk to a
1166 MIPS board attached to a serial line. This is available when
1167 you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}.
1169 @kindex target mips @var{port}
1170 To run a program on the board, start up @code{@value{GDBP}} with the
1171 name of your program as the argument. To connect to the board, use the
1172 command @samp{target mips @var{port}}, where @var{port} is the name of
1173 the serial port connected to the board. If the program has not already
1174 been downloaded to the board, you may use the @code{load} command to
1175 download it. You can then use all the usual @value{GDBN} commands.
1177 You can also specify @var{port} as a TCP connection (for instance, to a
1178 serial line managed by a terminal concentrator), using the syntax
1179 @code{@var{hostname}:@var{portnumber}}.
1181 @cindex @code{remotedebug}, MIPS protocol
1182 @c FIXME! For this to be useful, you must know something about the MIPS
1183 @c FIXME...protocol. Where is it described?
1184 You can see some debugging information about communications with the board
1185 by setting the @code{remotedebug} variable. If you set it to 1 using
1186 @samp{set remotedebug 1} every packet will be displayed. If you set it
1187 to 2 every character will be displayed. You can check the current value
1188 at any time with the command @samp{show remotedebug}.
1190 @cindex @code{timeout}, MIPS protocol
1191 @cindex @code{retransmit-timeout}, MIPS protocol
1193 @kindex show timeout
1194 @kindex set retransmit-timeout
1195 @kindex show retransmit-timeout
1196 You can control the timeout used while waiting for a packet, in the MIPS
1197 remote protocol, with the @code{set timeout @var{seconds}} command. The
1198 default is 5 seconds. Similarly, you can control the timeout used while
1199 waiting for an acknowledgement of a packet with the @code{set
1200 retransmit-timeout @var{seconds}} command. The default is 3 seconds.
1201 You can inspect both values with @code{show timeout} and @code{show
1202 retransmit-timeout}. (These commands are @emph{only} available when
1203 @value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.)
1205 @kindex set mipsfpu off
1206 @cindex MIPS remote floating point
1207 @cindex floating point, MIPS remote
1208 If your target board does not support the MIPS floating point
1209 coprocessor, use the command @samp{set mipsfpu off} (you may wish to put
1210 this in your @value{GDBINIT} file). This will tell @value{GDBN} how to
1211 find the return value of functions which return floating point values,
1212 and tell it to call functions on the board without saving the floating
1218 @subsection Simulated CPU target
1222 @cindex simulator, Z8000
1223 @cindex Z8000 simulator
1224 @cindex simulator, H8/300 or H8/500
1225 @cindex H8/300 or H8/500 simulator
1226 @cindex simulator, Hitachi SH
1227 @cindex Hitachi SH simulator
1228 @cindex CPU simulator
1229 For some configurations, @value{GDBN} includes a CPU simulator that you
1230 can use instead of a hardware CPU to debug your programs. Currently,
1231 a simulator is available when @value{GDBN} is configured to debug Zilog
1232 Z8000 or Hitachi microprocessor targets.
1237 @cindex simulator, H8/300 or H8/500
1238 @cindex Hitachi H8/300 or H8/500 simulator
1239 @cindex simulator, Hitachi SH
1240 @cindex Hitachi SH simulator
1241 When configured for debugging Hitachi microprocessor targets,
1242 @value{GDBN} includes a CPU simulator for the target chip (a Hitachi SH,
1247 @cindex simulator, Z8000
1248 @cindex Zilog Z8000 simulator
1249 When configured for debugging Zilog Z8000 targets, @value{GDBN} includes
1255 For the Z8000 family, @samp{target sim} simulates either the Z8002 (the
1256 unsegmented variant of the Z8000 architecture) or the Z8001 (the
1257 segmented variant). The simulator recognizes which architecture is
1258 appropriate by inspecting the object code.
1265 Debug programs on a simulated CPU
1267 (which CPU depends on the @value{GDBN} configuration)
1272 After specifying this target, you can debug programs for the simulated
1273 CPU in the same style as programs for your host computer; use the
1274 @code{file} command to load a new program image, the @code{run} command
1275 to run your program, and so on.
1277 As well as making available all the usual machine registers (see
1278 @code{info reg}), this debugging target provides three additional items
1279 of information as specially named registers:
1283 Counts clock-ticks in the simulator.
1286 Counts instructions run in the simulator.
1289 Execution time in 60ths of a second.
1292 You can refer to these values in @value{GDBN} expressions with the usual
1293 conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a
1294 conditional breakpoint that will suspend only after at least 5000
1295 simulated clock ticks.