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This is gdb.info, produced by makeinfo version 4.1 from ./gdb.texinfo.
INFO-DIR-SECTION Programming & development tools.
START-INFO-DIR-ENTRY
* Gdb: (gdb). The GNU debugger.
END-INFO-DIR-ENTRY
This file documents the GNU debugger GDB.
This is the Ninth Edition, December 2001, of `Debugging with GDB:
the GNU Source-Level Debugger' for GDB Version 5.3.
Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
1998,
1999, 2000, 2001, 2002 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Free Software" and "Free Software Needs Free
Documentation", with the Front-Cover Texts being "A GNU Manual," and
with the Back-Cover Texts as in (a) below.
(a) The Free Software Foundation's Back-Cover Text is: "You have
freedom to copy and modify this GNU Manual, like GNU software. Copies
published by the Free Software Foundation raise funds for GNU
development."
File: gdb.info, Node: Stub Contents, Next: Bootstrapping, Up: remote stub
What the stub can do for you
----------------------------
The debugging stub for your architecture supplies these three
subroutines:
`set_debug_traps'
This routine arranges for `handle_exception' to run when your
program stops. You must call this subroutine explicitly near the
beginning of your program.
`handle_exception'
This is the central workhorse, but your program never calls it
explicitly--the setup code arranges for `handle_exception' to run
when a trap is triggered.
`handle_exception' takes control when your program stops during
execution (for example, on a breakpoint), and mediates
communications with GDB on the host machine. This is where the
communications protocol is implemented; `handle_exception' acts as
the GDB representative on the target machine. It begins by
sending summary information on the state of your program, then
continues to execute, retrieving and transmitting any information
GDB needs, until you execute a GDB command that makes your program
resume; at that point, `handle_exception' returns control to your
own code on the target machine.
`breakpoint'
Use this auxiliary subroutine to make your program contain a
breakpoint. Depending on the particular situation, this may be
the only way for GDB to get control. For instance, if your target
machine has some sort of interrupt button, you won't need to call
this; pressing the interrupt button transfers control to
`handle_exception'--in effect, to GDB. On some machines, simply
receiving characters on the serial port may also trigger a trap;
again, in that situation, you don't need to call `breakpoint' from
your own program--simply running `target remote' from the host GDB
session gets control.
Call `breakpoint' if none of these is true, or if you simply want
to make certain your program stops at a predetermined point for the
start of your debugging session.
File: gdb.info, Node: Bootstrapping, Next: Debug Session, Prev: Stub Contents, Up: remote stub
What you must do for the stub
-----------------------------
The debugging stubs that come with GDB are set up for a particular
chip architecture, but they have no information about the rest of your
debugging target machine.
First of all you need to tell the stub how to communicate with the
serial port.
`int getDebugChar()'
Write this subroutine to read a single character from the serial
port. It may be identical to `getchar' for your target system; a
different name is used to allow you to distinguish the two if you
wish.
`void putDebugChar(int)'
Write this subroutine to write a single character to the serial
port. It may be identical to `putchar' for your target system; a
different name is used to allow you to distinguish the two if you
wish.
If you want GDB to be able to stop your program while it is running,
you need to use an interrupt-driven serial driver, and arrange for it
to stop when it receives a `^C' (`\003', the control-C character).
That is the character which GDB uses to tell the remote system to stop.
Getting the debugging target to return the proper status to GDB
probably requires changes to the standard stub; one quick and dirty way
is to just execute a breakpoint instruction (the "dirty" part is that
GDB reports a `SIGTRAP' instead of a `SIGINT').
Other routines you need to supply are:
`void exceptionHandler (int EXCEPTION_NUMBER, void *EXCEPTION_ADDRESS)'
Write this function to install EXCEPTION_ADDRESS in the exception
handling tables. You need to do this because the stub does not
have any way of knowing what the exception handling tables on your
target system are like (for example, the processor's table might
be in ROM, containing entries which point to a table in RAM).
EXCEPTION_NUMBER is the exception number which should be changed;
its meaning is architecture-dependent (for example, different
numbers might represent divide by zero, misaligned access, etc).
When this exception occurs, control should be transferred directly
to EXCEPTION_ADDRESS, and the processor state (stack, registers,
and so on) should be just as it is when a processor exception
occurs. So if you want to use a jump instruction to reach
EXCEPTION_ADDRESS, it should be a simple jump, not a jump to
subroutine.
For the 386, EXCEPTION_ADDRESS should be installed as an interrupt
gate so that interrupts are masked while the handler runs. The
gate should be at privilege level 0 (the most privileged level).
The SPARC and 68k stubs are able to mask interrupts themselves
without help from `exceptionHandler'.
`void flush_i_cache()'
On SPARC and SPARCLITE only, write this subroutine to flush the
instruction cache, if any, on your target machine. If there is no
instruction cache, this subroutine may be a no-op.
On target machines that have instruction caches, GDB requires this
function to make certain that the state of your program is stable.
You must also make sure this library routine is available:
`void *memset(void *, int, int)'
This is the standard library function `memset' that sets an area of
memory to a known value. If you have one of the free versions of
`libc.a', `memset' can be found there; otherwise, you must either
obtain it from your hardware manufacturer, or write your own.
If you do not use the GNU C compiler, you may need other standard
library subroutines as well; this varies from one stub to another, but
in general the stubs are likely to use any of the common library
subroutines which `gcc' generates as inline code.
File: gdb.info, Node: Debug Session, Prev: Bootstrapping, Up: remote stub
Putting it all together
-----------------------
In summary, when your program is ready to debug, you must follow
these steps.
1. Make sure you have defined the supporting low-level routines
(*note What you must do for the stub: Bootstrapping.):
`getDebugChar', `putDebugChar',
`flush_i_cache', `memset', `exceptionHandler'.
2. Insert these lines near the top of your program:
set_debug_traps();
breakpoint();
3. For the 680x0 stub only, you need to provide a variable called
`exceptionHook'. Normally you just use:
void (*exceptionHook)() = 0;
but if before calling `set_debug_traps', you set it to point to a
function in your program, that function is called when `GDB'
continues after stopping on a trap (for example, bus error). The
function indicated by `exceptionHook' is called with one
parameter: an `int' which is the exception number.
4. Compile and link together: your program, the GDB debugging stub for
your target architecture, and the supporting subroutines.
5. Make sure you have a serial connection between your target machine
and the GDB host, and identify the serial port on the host.
6. Download your program to your target machine (or get it there by
whatever means the manufacturer provides), and start it.
7. To start remote debugging, run GDB on the host machine, and specify
as an executable file the program that is running in the remote
machine. This tells GDB how to find your program's symbols and
the contents of its pure text.
8. Establish communication using the `target remote' command. Its
argument specifies how to communicate with the target
machine--either via a devicename attached to a direct serial line,
or a TCP or UDP port (usually to a terminal server which in turn
has a serial line to the target). For example, to use a serial
line connected to the device named `/dev/ttyb':
target remote /dev/ttyb
To use a TCP connection, use an argument of the form `HOST:PORT'
or `tcp:HOST:PORT'. For example, to connect to port 2828 on a
terminal server named `manyfarms':
target remote manyfarms:2828
If your remote target is actually running on the same machine as
your debugger session (e.g. a simulator of your target running on
the same host), you can omit the hostname. For example, to connect
to port 1234 on your local machine:
target remote :1234
Note that the colon is still required here.
To use a UDP connection, use an argument of the form
`udp:HOST:PORT'. For example, to connect to UDP port 2828 on a
terminal server named `manyfarms':
target remote udp:manyfarms:2828
When using a UDP connection for remote debugging, you should keep
in mind that the `U' stands for "Unreliable". UDP can silently
drop packets on busy or unreliable networks, which will cause
havoc with your debugging session.
Now you can use all the usual commands to examine and change data
and to step and continue the remote program.
To resume the remote program and stop debugging it, use the `detach'
command.
Whenever GDB is waiting for the remote program, if you type the
interrupt character (often <C-C>), GDB attempts to stop the program.
This may or may not succeed, depending in part on the hardware and the
serial drivers the remote system uses. If you type the interrupt
character once again, GDB displays this prompt:
Interrupted while waiting for the program.
Give up (and stop debugging it)? (y or n)
If you type `y', GDB abandons the remote debugging session. (If you
decide you want to try again later, you can use `target remote' again
to connect once more.) If you type `n', GDB goes back to waiting.
File: gdb.info, Node: Configurations, Next: Controlling GDB, Prev: Remote Debugging, Up: Top
Configuration-Specific Information
**********************************
While nearly all GDB commands are available for all native and cross
versions of the debugger, there are some exceptions. This chapter
describes things that are only available in certain configurations.
There are three major categories of configurations: native
configurations, where the host and target are the same, embedded
operating system configurations, which are usually the same for several
different processor architectures, and bare embedded processors, which
are quite different from each other.
* Menu:
* Native::
* Embedded OS::
* Embedded Processors::
* Architectures::
File: gdb.info, Node: Native, Next: Embedded OS, Up: Configurations
Native
======
This section describes details specific to particular native
configurations.
* Menu:
* HP-UX:: HP-UX
* SVR4 Process Information:: SVR4 process information
* DJGPP Native:: Features specific to the DJGPP port
* Cygwin Native:: Features specific to the Cygwin port
File: gdb.info, Node: HP-UX, Next: SVR4 Process Information, Up: Native
HP-UX
-----
On HP-UX systems, if you refer to a function or variable name that
begins with a dollar sign, GDB searches for a user or system name
first, before it searches for a convenience variable.
File: gdb.info, Node: SVR4 Process Information, Next: DJGPP Native, Prev: HP-UX, Up: Native
SVR4 process information
------------------------
Many versions of SVR4 provide a facility called `/proc' that can be
used to examine the image of a running process using file-system
subroutines. If GDB is configured for an operating system with this
facility, the command `info proc' is available to report on several
kinds of information about the process running your program. `info
proc' works only on SVR4 systems that include the `procfs' code. This
includes OSF/1 (Digital Unix), Solaris, Irix, and Unixware, but not
HP-UX or GNU/Linux, for example.
`info proc'
Summarize available information about the process.
`info proc mappings'
Report on the address ranges accessible in the program, with
information on whether your program may read, write, or execute
each range.
File: gdb.info, Node: DJGPP Native, Next: Cygwin Native, Prev: SVR4 Process Information, Up: Native
Features for Debugging DJGPP Programs
-------------------------------------
DJGPP is the port of GNU development tools to MS-DOS and MS-Windows.
DJGPP programs are 32-bit protected-mode programs that use the "DPMI"
(DOS Protected-Mode Interface) API to run on top of real-mode DOS
systems and their emulations.
GDB supports native debugging of DJGPP programs, and defines a few
commands specific to the DJGPP port. This subsection describes those
commands.
`info dos'
This is a prefix of DJGPP-specific commands which print
information about the target system and important OS structures.
`info dos sysinfo'
This command displays assorted information about the underlying
platform: the CPU type and features, the OS version and flavor, the
DPMI version, and the available conventional and DPMI memory.
`info dos gdt'
`info dos ldt'
`info dos idt'
These 3 commands display entries from, respectively, Global, Local,
and Interrupt Descriptor Tables (GDT, LDT, and IDT). The
descriptor tables are data structures which store a descriptor for
each segment that is currently in use. The segment's selector is
an index into a descriptor table; the table entry for that index
holds the descriptor's base address and limit, and its attributes
and access rights.
A typical DJGPP program uses 3 segments: a code segment, a data
segment (used for both data and the stack), and a DOS segment
(which allows access to DOS/BIOS data structures and absolute
addresses in conventional memory). However, the DPMI host will
usually define additional segments in order to support the DPMI
environment.
These commands allow to display entries from the descriptor tables.
Without an argument, all entries from the specified table are
displayed. An argument, which should be an integer expression,
means display a single entry whose index is given by the argument.
For example, here's a convenient way to display information about
the debugged program's data segment:
`(gdb) info dos ldt $ds'
`0x13f: base=0x11970000 limit=0x0009ffff 32-Bit Data (Read/Write, Exp-up)'
This comes in handy when you want to see whether a pointer is
outside the data segment's limit (i.e. "garbled").
`info dos pde'
`info dos pte'
These two commands display entries from, respectively, the Page
Directory and the Page Tables. Page Directories and Page Tables
are data structures which control how virtual memory addresses are
mapped into physical addresses. A Page Table includes an entry
for every page of memory that is mapped into the program's address
space; there may be several Page Tables, each one holding up to
4096 entries. A Page Directory has up to 4096 entries, one each
for every Page Table that is currently in use.
Without an argument, `info dos pde' displays the entire Page
Directory, and `info dos pte' displays all the entries in all of
the Page Tables. An argument, an integer expression, given to the
`info dos pde' command means display only that entry from the Page
Directory table. An argument given to the `info dos pte' command
means display entries from a single Page Table, the one pointed to
by the specified entry in the Page Directory.
These commands are useful when your program uses "DMA" (Direct
Memory Access), which needs physical addresses to program the DMA
controller.
These commands are supported only with some DPMI servers.
`info dos address-pte ADDR'
This command displays the Page Table entry for a specified linear
address. The argument linear address ADDR should already have the
appropriate segment's base address added to it, because this
command accepts addresses which may belong to _any_ segment. For
example, here's how to display the Page Table entry for the page
where the variable `i' is stored:
`(gdb) info dos address-pte __djgpp_base_address + (char *)&i'
`Page Table entry for address 0x11a00d30:'
`Base=0x02698000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0xd30'
This says that `i' is stored at offset `0xd30' from the page whose
physical base address is `0x02698000', and prints all the
attributes of that page.
Note that you must cast the addresses of variables to a `char *',
since otherwise the value of `__djgpp_base_address', the base
address of all variables and functions in a DJGPP program, will be
added using the rules of C pointer arithmetics: if `i' is declared
an `int', GDB will add 4 times the value of `__djgpp_base_address'
to the address of `i'.
Here's another example, it displays the Page Table entry for the
transfer buffer:
`(gdb) info dos address-pte *((unsigned *)&_go32_info_block + 3)'
`Page Table entry for address 0x29110:'
`Base=0x00029000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0x110'
(The `+ 3' offset is because the transfer buffer's address is the
3rd member of the `_go32_info_block' structure.) The output of
this command clearly shows that addresses in conventional memory
are mapped 1:1, i.e. the physical and linear addresses are
identical.
This command is supported only with some DPMI servers.
File: gdb.info, Node: Cygwin Native, Prev: DJGPP Native, Up: Native
Features for Debugging MS Windows PE executables
------------------------------------------------
GDB supports native debugging of MS Windows programs, and defines a
few commands specific to the Cygwin port. This subsection describes
those commands.
`info w32'
This is a prefix of MS Windows specific commands which print
information about the target system and important OS structures.
`info w32 selector'
This command displays information returned by the Win32 API
`GetThreadSelectorEntry' function. It takes an optional argument
that is evaluated to a long value to give the information about
this given selector. Without argument, this command displays
information about the the six segment registers.
`info dll'
This is a Cygwin specific alias of info shared.
`dll-symbols'
This command loads symbols from a dll similarly to add-sym command
but without the need to specify a base address.
`set new-console MODE'
If MODE is `on' the debuggee will be started in a new console on
next start. If MODE is `off'i, the debuggee will be started in
the same console as the debugger.
`show new-console'
Displays whether a new console is used when the debuggee is
started.
`set new-group MODE'
This boolean value controls whether the debuggee should start a
new group or stay in the same group as the debugger. This affects
the way the Windows OS handles Ctrl-C.
`show new-group'
Displays current value of new-group boolean.
`set debugevents'
This boolean value adds debug output concerning events seen by the
debugger.
`set debugexec'
This boolean value adds debug output concerning execute events
seen by the debugger.
`set debugexceptions'
This boolean value adds debug ouptut concerning exception events
seen by the debugger.
`set debugmemory'
This boolean value adds debug ouptut concerning memory events seen
by the debugger.
`set shell'
This boolean values specifies whether the debuggee is called via a
shell or directly (default value is on).
`show shell'
Displays if the debuggee will be started with a shell.
File: gdb.info, Node: Embedded OS, Next: Embedded Processors, Prev: Native, Up: Configurations
Embedded Operating Systems
==========================
This section describes configurations involving the debugging of
embedded operating systems that are available for several different
architectures.
* Menu:
* VxWorks:: Using GDB with VxWorks
GDB includes the ability to debug programs running on various
real-time operating systems.
File: gdb.info, Node: VxWorks, Up: Embedded OS
Using GDB with VxWorks
----------------------
`target vxworks MACHINENAME'
A VxWorks system, attached via TCP/IP. The argument MACHINENAME
is the target system's machine name or IP address.
On VxWorks, `load' links FILENAME dynamically on the current target
system as well as adding its symbols in GDB.
GDB enables developers to spawn and debug tasks running on networked
VxWorks targets from a Unix host. Already-running tasks spawned from
the VxWorks shell can also be debugged. GDB uses code that runs on
both the Unix host and on the VxWorks target. The program `gdb' is
installed and executed on the Unix host. (It may be installed with the
name `vxgdb', to distinguish it from a GDB for debugging programs on
the host itself.)
`VxWorks-timeout ARGS'
All VxWorks-based targets now support the option `vxworks-timeout'.
This option is set by the user, and ARGS represents the number of
seconds GDB waits for responses to rpc's. You might use this if
your VxWorks target is a slow software simulator or is on the far
side of a thin network line.
The following information on connecting to VxWorks was current when
this manual was produced; newer releases of VxWorks may use revised
procedures.
To use GDB with VxWorks, you must rebuild your VxWorks kernel to
include the remote debugging interface routines in the VxWorks library
`rdb.a'. To do this, define `INCLUDE_RDB' in the VxWorks configuration
file `configAll.h' and rebuild your VxWorks kernel. The resulting
kernel contains `rdb.a', and spawns the source debugging task
`tRdbTask' when VxWorks is booted. For more information on configuring
and remaking VxWorks, see the manufacturer's manual.
Once you have included `rdb.a' in your VxWorks system image and set
your Unix execution search path to find GDB, you are ready to run GDB.
From your Unix host, run `gdb' (or `vxgdb', depending on your
installation).
GDB comes up showing the prompt:
(vxgdb)
* Menu:
* VxWorks Connection:: Connecting to VxWorks
* VxWorks Download:: VxWorks download
* VxWorks Attach:: Running tasks
File: gdb.info, Node: VxWorks Connection, Next: VxWorks Download, Up: VxWorks
Connecting to VxWorks
.....................
The GDB command `target' lets you connect to a VxWorks target on the
network. To connect to a target whose host name is "`tt'", type:
(vxgdb) target vxworks tt
GDB displays messages like these:
Attaching remote machine across net...
Connected to tt.
GDB then attempts to read the symbol tables of any object modules
loaded into the VxWorks target since it was last booted. GDB locates
these files by searching the directories listed in the command search
path (*note Your program's environment: Environment.); if it fails to
find an object file, it displays a message such as:
prog.o: No such file or directory.
When this happens, add the appropriate directory to the search path
with the GDB command `path', and execute the `target' command again.
File: gdb.info, Node: VxWorks Download, Next: VxWorks Attach, Prev: VxWorks Connection, Up: VxWorks
VxWorks download
................
If you have connected to the VxWorks target and you want to debug an
object that has not yet been loaded, you can use the GDB `load' command
to download a file from Unix to VxWorks incrementally. The object file
given as an argument to the `load' command is actually opened twice:
first by the VxWorks target in order to download the code, then by GDB
in order to read the symbol table. This can lead to problems if the
current working directories on the two systems differ. If both systems
have NFS mounted the same filesystems, you can avoid these problems by
using absolute paths. Otherwise, it is simplest to set the working
directory on both systems to the directory in which the object file
resides, and then to reference the file by its name, without any path.
For instance, a program `prog.o' may reside in `VXPATH/vw/demo/rdb' in
VxWorks and in `HOSTPATH/vw/demo/rdb' on the host. To load this
program, type this on VxWorks:
-> cd "VXPATH/vw/demo/rdb"
Then, in GDB, type:
(vxgdb) cd HOSTPATH/vw/demo/rdb
(vxgdb) load prog.o
GDB displays a response similar to this:
Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
You can also use the `load' command to reload an object module after
editing and recompiling the corresponding source file. Note that this
makes GDB delete all currently-defined breakpoints, auto-displays, and
convenience variables, and to clear the value history. (This is
necessary in order to preserve the integrity of debugger's data
structures that reference the target system's symbol table.)
File: gdb.info, Node: VxWorks Attach, Prev: VxWorks Download, Up: VxWorks
Running tasks
.............
You can also attach to an existing task using the `attach' command as
follows:
(vxgdb) attach TASK
where TASK is the VxWorks hexadecimal task ID. The task can be running
or suspended when you attach to it. Running tasks are suspended at the
time of attachment.
File: gdb.info, Node: Embedded Processors, Next: Architectures, Prev: Embedded OS, Up: Configurations
Embedded Processors
===================
This section goes into details specific to particular embedded
configurations.
* Menu:
* ARM:: ARM
* H8/300:: Hitachi H8/300
* H8/500:: Hitachi H8/500
* i960:: Intel i960
* M32R/D:: Mitsubishi M32R/D
* M68K:: Motorola M68K
* MIPS Embedded:: MIPS Embedded
* PA:: HP PA Embedded
* PowerPC: PowerPC
* SH:: Hitachi SH
* Sparclet:: Tsqware Sparclet
* Sparclite:: Fujitsu Sparclite
* ST2000:: Tandem ST2000
* Z8000:: Zilog Z8000
File: gdb.info, Node: ARM, Next: H8/300, Up: Embedded Processors
ARM
---
`target rdi DEV'
ARM Angel monitor, via RDI library interface to ADP protocol. You
may use this target to communicate with both boards running the
Angel monitor, or with the EmbeddedICE JTAG debug device.
`target rdp DEV'
ARM Demon monitor.
File: gdb.info, Node: H8/300, Next: H8/500, Prev: ARM, Up: Embedded Processors
Hitachi H8/300
--------------
`target hms DEV'
A Hitachi SH, H8/300, or H8/500 board, attached via serial line to
your host. Use special commands `device' and `speed' to control
the serial line and the communications speed used.
`target e7000 DEV'
E7000 emulator for Hitachi H8 and SH.
`target sh3 DEV'
`target sh3e DEV'
Hitachi SH-3 and SH-3E target systems.
When you select remote debugging to a Hitachi SH, H8/300, or H8/500
board, the `load' command downloads your program to the Hitachi board
and also opens it as the current executable target for GDB on your host
(like the `file' command).
GDB needs to know these things to talk to your Hitachi SH, H8/300,
or H8/500:
1. that you want to use `target hms', the remote debugging interface
for Hitachi microprocessors, or `target e7000', the in-circuit
emulator for the Hitachi SH and the Hitachi 300H. (`target hms' is
the default when GDB is configured specifically for the Hitachi SH,
H8/300, or H8/500.)
2. what serial device connects your host to your Hitachi board (the
first serial device available on your host is the default).
3. what speed to use over the serial device.
* Menu:
* Hitachi Boards:: Connecting to Hitachi boards.
* Hitachi ICE:: Using the E7000 In-Circuit Emulator.
* Hitachi Special:: Special GDB commands for Hitachi micros.
File: gdb.info, Node: Hitachi Boards, Next: Hitachi ICE, Up: H8/300
Connecting to Hitachi boards
............................
Use the special `GDB' command `device PORT' if you need to
explicitly set the serial device. The default PORT is the first
available port on your host. This is only necessary on Unix hosts,
where it is typically something like `/dev/ttya'.
`GDB' has another special command to set the communications speed:
`speed BPS'. This command also is only used from Unix hosts; on DOS
hosts, set the line speed as usual from outside GDB with the DOS `mode'
command (for instance, `mode com2:9600,n,8,1,p' for a 9600bps
connection).
The `device' and `speed' commands are available only when you use a
Unix host to debug your Hitachi microprocessor programs. If you use a
DOS host, GDB depends on an auxiliary terminate-and-stay-resident
program called `asynctsr' to communicate with the development board
through a PC serial port. You must also use the DOS `mode' command to
set up the serial port on the DOS side.
The following sample session illustrates the steps needed to start a
program under GDB control on an H8/300. The example uses a sample
H8/300 program called `t.x'. The procedure is the same for the Hitachi
SH and the H8/500.
First hook up your development board. In this example, we use a
board attached to serial port `COM2'; if you use a different serial
port, substitute its name in the argument of the `mode' command. When
you call `asynctsr', the auxiliary comms program used by the debugger,
you give it just the numeric part of the serial port's name; for
example, `asyncstr 2' below runs `asyncstr' on `COM2'.
C:\H8300\TEST> asynctsr 2
C:\H8300\TEST> mode com2:9600,n,8,1,p
Resident portion of MODE loaded
COM2: 9600, n, 8, 1, p
_Warning:_ We have noticed a bug in PC-NFS that conflicts with
`asynctsr'. If you also run PC-NFS on your DOS host, you may need
to disable it, or even boot without it, to use `asynctsr' to
control your development board.
Now that serial communications are set up, and the development board
is connected, you can start up GDB. Call `gdb' with the name of your
program as the argument. `GDB' prompts you, as usual, with the prompt
`(gdb)'. Use two special commands to begin your debugging session:
`target hms' to specify cross-debugging to the Hitachi board, and the
`load' command to download your program to the board. `load' displays
the names of the program's sections, and a `*' for each 2K of data
downloaded. (If you want to refresh GDB data on symbols or on the
executable file without downloading, use the GDB commands `file' or
`symbol-file'. These commands, and `load' itself, are described in
*Note Commands to specify files: Files.)
(eg-C:\H8300\TEST) gdb t.x
GDB is free software and you are welcome to distribute copies
of it under certain conditions; type "show copying" to see
the conditions.
There is absolutely no warranty for GDB; type "show warranty"
for details.
GDB 5.3, Copyright 1992 Free Software Foundation, Inc...
(gdb) target hms
Connected to remote H8/300 HMS system.
(gdb) load t.x
.text : 0x8000 .. 0xabde ***********
.data : 0xabde .. 0xad30 *
.stack : 0xf000 .. 0xf014 *
At this point, you're ready to run or debug your program. From here
on, you can use all the usual GDB commands. The `break' command sets
breakpoints; the `run' command starts your program; `print' or `x'
display data; the `continue' command resumes execution after stopping
at a breakpoint. You can use the `help' command at any time to find
out more about GDB commands.
Remember, however, that _operating system_ facilities aren't
available on your development board; for example, if your program hangs,
you can't send an interrupt--but you can press the RESET switch!
Use the RESET button on the development board
* to interrupt your program (don't use `ctl-C' on the DOS host--it
has no way to pass an interrupt signal to the development board);
and
* to return to the GDB command prompt after your program finishes
normally. The communications protocol provides no other way for
GDB to detect program completion.
In either case, GDB sees the effect of a RESET on the development
board as a "normal exit" of your program.
File: gdb.info, Node: Hitachi ICE, Next: Hitachi Special, Prev: Hitachi Boards, Up: H8/300
Using the E7000 in-circuit emulator
...................................
You can use the E7000 in-circuit emulator to develop code for either
the Hitachi SH or the H8/300H. Use one of these forms of the `target
e7000' command to connect GDB to your E7000:
`target e7000 PORT SPEED'
Use this form if your E7000 is connected to a serial port. The
PORT argument identifies what serial port to use (for example,
`com2'). The third argument is the line speed in bits per second
(for example, `9600').
`target e7000 HOSTNAME'
If your E7000 is installed as a host on a TCP/IP network, you can
just specify its hostname; GDB uses `telnet' to connect.
File: gdb.info, Node: Hitachi Special, Prev: Hitachi ICE, Up: H8/300
Special GDB commands for Hitachi micros
.......................................
Some GDB commands are available only for the H8/300:
`set machine h8300'
`set machine h8300h'
Condition GDB for one of the two variants of the H8/300
architecture with `set machine'. You can use `show machine' to
check which variant is currently in effect.
File: gdb.info, Node: H8/500, Next: i960, Prev: H8/300, Up: Embedded Processors
H8/500
------
`set memory MOD'
`show memory'
Specify which H8/500 memory model (MOD) you are using with `set
memory'; check which memory model is in effect with `show memory'.
The accepted values for MOD are `small', `big', `medium', and
`compact'.
File: gdb.info, Node: i960, Next: M32R/D, Prev: H8/500, Up: Embedded Processors
Intel i960
----------
`target mon960 DEV'
MON960 monitor for Intel i960.
`target nindy DEVICENAME'
An Intel 960 board controlled by a Nindy Monitor. DEVICENAME is
the name of the serial device to use for the connection, e.g.
`/dev/ttya'.
"Nindy" is a ROM Monitor program for Intel 960 target systems. When
GDB is configured to control a remote Intel 960 using Nindy, you can
tell GDB how to connect to the 960 in several ways:
* Through command line options specifying serial port, version of the
Nindy protocol, and communications speed;
* By responding to a prompt on startup;
* By using the `target' command at any point during your GDB
session. *Note Commands for managing targets: Target Commands.
With the Nindy interface to an Intel 960 board, `load' downloads
FILENAME to the 960 as well as adding its symbols in GDB.
* Menu:
* Nindy Startup:: Startup with Nindy
* Nindy Options:: Options for Nindy
* Nindy Reset:: Nindy reset command
File: gdb.info, Node: Nindy Startup, Next: Nindy Options, Up: i960
Startup with Nindy
..................
If you simply start `gdb' without using any command-line options,
you are prompted for what serial port to use, _before_ you reach the
ordinary GDB prompt:
Attach /dev/ttyNN -- specify NN, or "quit" to quit:
Respond to the prompt with whatever suffix (after `/dev/tty')
identifies the serial port you want to use. You can, if you choose,
simply start up with no Nindy connection by responding to the prompt
with an empty line. If you do this and later wish to attach to Nindy,
use `target' (*note Commands for managing targets: Target Commands.).
File: gdb.info, Node: Nindy Options, Next: Nindy Reset, Prev: Nindy Startup, Up: i960
Options for Nindy
.................
These are the startup options for beginning your GDB session with a
Nindy-960 board attached:
`-r PORT'
Specify the serial port name of a serial interface to be used to
connect to the target system. This option is only available when
GDB is configured for the Intel 960 target architecture. You may
specify PORT as any of: a full pathname (e.g. `-r /dev/ttya'), a
device name in `/dev' (e.g. `-r ttya'), or simply the unique
suffix for a specific `tty' (e.g. `-r a').
`-O'
(An uppercase letter "O", not a zero.) Specify that GDB should use
the "old" Nindy monitor protocol to connect to the target system.
This option is only available when GDB is configured for the Intel
960 target architecture.
_Warning:_ if you specify `-O', but are actually trying to
connect to a target system that expects the newer protocol,
the connection fails, appearing to be a speed mismatch. GDB
repeatedly attempts to reconnect at several different line
speeds. You can abort this process with an interrupt.
`-brk'
Specify that GDB should first send a `BREAK' signal to the target
system, in an attempt to reset it, before connecting to a Nindy
target.
_Warning:_ Many target systems do not have the hardware that
this requires; it only works with a few boards.
The standard `-b' option controls the line speed used on the serial
port.
File: gdb.info, Node: Nindy Reset, Prev: Nindy Options, Up: i960
Nindy reset command
...................
`reset'
For a Nindy target, this command sends a "break" to the remote
target system; this is only useful if the target has been equipped
with a circuit to perform a hard reset (or some other interesting
action) when a break is detected.
File: gdb.info, Node: M32R/D, Next: M68K, Prev: i960, Up: Embedded Processors
Mitsubishi M32R/D
-----------------
`target m32r DEV'
Mitsubishi M32R/D ROM monitor.
File: gdb.info, Node: M68K, Next: MIPS Embedded, Prev: M32R/D, Up: Embedded Processors
M68k
----
The Motorola m68k configuration includes ColdFire support, and
target command for the following ROM monitors.
`target abug DEV'
ABug ROM monitor for M68K.
`target cpu32bug DEV'
CPU32BUG monitor, running on a CPU32 (M68K) board.
`target dbug DEV'
dBUG ROM monitor for Motorola ColdFire.
`target est DEV'
EST-300 ICE monitor, running on a CPU32 (M68K) board.
`target rom68k DEV'
ROM 68K monitor, running on an M68K IDP board.
If GDB is configured with `m68*-ericsson-*', it will instead have
only a single special target command:
`target es1800 DEV'
ES-1800 emulator for M68K.
[context?]
`target rombug DEV'
ROMBUG ROM monitor for OS/9000.
File: gdb.info, Node: MIPS Embedded, Next: PA, Prev: M68K, Up: Embedded Processors
MIPS Embedded
-------------
GDB can use the MIPS remote debugging protocol to talk to a MIPS
board attached to a serial line. This is available when you configure
GDB with `--target=mips-idt-ecoff'.
Use these GDB commands to specify the connection to your target
board:
`target mips PORT'
To run a program on the board, start up `gdb' with the name of
your program as the argument. To connect to the board, use the
command `target mips PORT', where PORT is the name of the serial
port connected to the board. If the program has not already been
downloaded to the board, you may use the `load' command to
download it. You can then use all the usual GDB commands.
For example, this sequence connects to the target board through a
serial port, and loads and runs a program called PROG through the
debugger:
host$ gdb PROG
GDB is free software and ...
(gdb) target mips /dev/ttyb
(gdb) load PROG
(gdb) run
`target mips HOSTNAME:PORTNUMBER'
On some GDB host configurations, you can specify a TCP connection
(for instance, to a serial line managed by a terminal
concentrator) instead of a serial port, using the syntax
`HOSTNAME:PORTNUMBER'.
`target pmon PORT'
PMON ROM monitor.
`target ddb PORT'
NEC's DDB variant of PMON for Vr4300.
`target lsi PORT'
LSI variant of PMON.
`target r3900 DEV'
Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips.
`target array DEV'
Array Tech LSI33K RAID controller board.
GDB also supports these special commands for MIPS targets:
`set processor ARGS'
`show processor'
Use the `set processor' command to set the type of MIPS processor
when you want to access processor-type-specific registers. For
example, `set processor R3041' tells GDB to use the CPU registers
appropriate for the 3041 chip. Use the `show processor' command
to see what MIPS processor GDB is using. Use the `info reg'
command to see what registers GDB is using.
`set mipsfpu double'
`set mipsfpu single'
`set mipsfpu none'
`show mipsfpu'
If your target board does not support the MIPS floating point
coprocessor, you should use the command `set mipsfpu none' (if you
need this, you may wish to put the command in your GDB init file).
This tells GDB how to find the return value of functions which
return floating point values. It also allows GDB to avoid saving
the floating point registers when calling functions on the board.
If you are using a floating point coprocessor with only single
precision floating point support, as on the R4650 processor, use
the command `set mipsfpu single'. The default double precision
floating point coprocessor may be selected using `set mipsfpu
double'.
In previous versions the only choices were double precision or no
floating point, so `set mipsfpu on' will select double precision
and `set mipsfpu off' will select no floating point.
As usual, you can inquire about the `mipsfpu' variable with `show
mipsfpu'.
`set remotedebug N'
`show remotedebug'
You can see some debugging information about communications with
the board by setting the `remotedebug' variable. If you set it to
`1' using `set remotedebug 1', every packet is displayed. If you
set it to `2', every character is displayed. You can check the
current value at any time with the command `show remotedebug'.
`set timeout SECONDS'
`set retransmit-timeout SECONDS'
`show timeout'
`show retransmit-timeout'
You can control the timeout used while waiting for a packet, in
the MIPS remote protocol, with the `set timeout SECONDS' command.
The default is 5 seconds. Similarly, you can control the timeout
used while waiting for an acknowledgement of a packet with the `set
retransmit-timeout SECONDS' command. The default is 3 seconds.
You can inspect both values with `show timeout' and `show
retransmit-timeout'. (These commands are _only_ available when
GDB is configured for `--target=mips-idt-ecoff'.)
The timeout set by `set timeout' does not apply when GDB is
waiting for your program to stop. In that case, GDB waits forever
because it has no way of knowing how long the program is going to
run before stopping.
File: gdb.info, Node: PowerPC, Next: SH, Prev: PA, Up: Embedded Processors
PowerPC
-------
`target dink32 DEV'
DINK32 ROM monitor.
`target ppcbug DEV'
`target ppcbug1 DEV'
PPCBUG ROM monitor for PowerPC.
`target sds DEV'
SDS monitor, running on a PowerPC board (such as Motorola's ADS).
File: gdb.info, Node: PA, Next: PowerPC, Prev: MIPS Embedded, Up: Embedded Processors
HP PA Embedded
--------------
`target op50n DEV'
OP50N monitor, running on an OKI HPPA board.
`target w89k DEV'
W89K monitor, running on a Winbond HPPA board.
File: gdb.info, Node: SH, Next: Sparclet, Prev: PowerPC, Up: Embedded Processors
Hitachi SH
----------
`target hms DEV'
A Hitachi SH board attached via serial line to your host. Use
special commands `device' and `speed' to control the serial line
and the communications speed used.
`target e7000 DEV'
E7000 emulator for Hitachi SH.
`target sh3 DEV'
`target sh3e DEV'
Hitachi SH-3 and SH-3E target systems.
File: gdb.info, Node: Sparclet, Next: Sparclite, Prev: SH, Up: Embedded Processors
Tsqware Sparclet
----------------
GDB enables developers to debug tasks running on Sparclet targets
from a Unix host. GDB uses code that runs on both the Unix host and on
the Sparclet target. The program `gdb' is installed and executed on
the Unix host.
`remotetimeout ARGS'
GDB supports the option `remotetimeout'. This option is set by
the user, and ARGS represents the number of seconds GDB waits for
responses.
When compiling for debugging, include the options `-g' to get debug
information and `-Ttext' to relocate the program to where you wish to
load it on the target. You may also want to add the options `-n' or
`-N' in order to reduce the size of the sections. Example:
sparclet-aout-gcc prog.c -Ttext 0x12010000 -g -o prog -N
You can use `objdump' to verify that the addresses are what you
intended:
sparclet-aout-objdump --headers --syms prog
Once you have set your Unix execution search path to find GDB, you
are ready to run GDB. From your Unix host, run `gdb' (or
`sparclet-aout-gdb', depending on your installation).
GDB comes up showing the prompt:
(gdbslet)
* Menu:
* Sparclet File:: Setting the file to debug
* Sparclet Connection:: Connecting to Sparclet
* Sparclet Download:: Sparclet download
* Sparclet Execution:: Running and debugging
File: gdb.info, Node: Sparclet File, Next: Sparclet Connection, Up: Sparclet
Setting file to debug
.....................
The GDB command `file' lets you choose with program to debug.
(gdbslet) file prog
GDB then attempts to read the symbol table of `prog'. GDB locates
the file by searching the directories listed in the command search path.
If the file was compiled with debug information (option "-g"), source
files will be searched as well. GDB locates the source files by
searching the directories listed in the directory search path (*note
Your program's environment: Environment.). If it fails to find a file,
it displays a message such as:
prog: No such file or directory.
When this happens, add the appropriate directories to the search
paths with the GDB commands `path' and `dir', and execute the `target'
command again.
File: gdb.info, Node: Sparclet Connection, Next: Sparclet Download, Prev: Sparclet File, Up: Sparclet
Connecting to Sparclet
......................
The GDB command `target' lets you connect to a Sparclet target. To
connect to a target on serial port "`ttya'", type:
(gdbslet) target sparclet /dev/ttya
Remote target sparclet connected to /dev/ttya
main () at ../prog.c:3
GDB displays messages like these:
Connected to ttya.
File: gdb.info, Node: Sparclet Download, Next: Sparclet Execution, Prev: Sparclet Connection, Up: Sparclet
Sparclet download
.................
Once connected to the Sparclet target, you can use the GDB `load'
command to download the file from the host to the target. The file
name and load offset should be given as arguments to the `load' command.
Since the file format is aout, the program must be loaded to the
starting address. You can use `objdump' to find out what this value
is. The load offset is an offset which is added to the VMA (virtual
memory address) of each of the file's sections. For instance, if the
program `prog' was linked to text address 0x1201000, with data at
0x12010160 and bss at 0x12010170, in GDB, type:
(gdbslet) load prog 0x12010000
Loading section .text, size 0xdb0 vma 0x12010000
If the code is loaded at a different address then what the program
was linked to, you may need to use the `section' and `add-symbol-file'
commands to tell GDB where to map the symbol table.
File: gdb.info, Node: Sparclet Execution, Prev: Sparclet Download, Up: Sparclet
Running and debugging
.....................
You can now begin debugging the task using GDB's execution control
commands, `b', `step', `run', etc. See the GDB manual for the list of
commands.
(gdbslet) b main
Breakpoint 1 at 0x12010000: file prog.c, line 3.
(gdbslet) run
Starting program: prog
Breakpoint 1, main (argc=1, argv=0xeffff21c) at prog.c:3
3 char *symarg = 0;
(gdbslet) step
4 char *execarg = "hello!";
(gdbslet)
File: gdb.info, Node: Sparclite, Next: ST2000, Prev: Sparclet, Up: Embedded Processors
Fujitsu Sparclite
-----------------
`target sparclite DEV'
Fujitsu sparclite boards, used only for the purpose of loading.
You must use an additional command to debug the program. For
example: target remote DEV using GDB standard remote protocol.
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