cyggdb.htm

mips架构的bootloader,99左右的版本 但源代码现在没人更新了

		<title>GNU's gdb from Cygnus Support</title>
		<h1 align=center>GNU's gdb from Cygnus Support</h1>

<!--INDEX "Source-level debug with Cygnus' gdb" -->

To use the debug <a href="mondef.htm">Monitor</a> with GNU's gdb,
connect the serial port that gdb will use, to the Monitor's tty0 (the
console) on the target board.  i.e., gdb only uses one serial port.<p>

<!--
If necessary, use the <a href="c_set.htm">set</a> command to set your
<a href="mondef.htm">Monitor</a>'s prompt to "PMON> ".  Gdb is
hardwired to expect that string, and will not work with any other value
(note the space after the ">").<p>
-->

Compile and link your modules with the -g option.  This will generate
the extra information that is required by gdb. For example,<p>

<pre>
	pmcc -g -o bubble bubble.c
</pre>

Invoke gdb.<p>

<pre>
	% mips-lsi-elf-gdb -b 9600 bubble
</pre>

where 'bubble' is the name of the object file that you are debugging.
The option "-b 9600" specifies that 9600 baud will be used for the
Host-to-Target communications.<p>

By default gdb from Cygnus Support runs in a windowed mode. However, it
the time of writing, the windowed mode was incomplete/buggy, so you might
prefer to run it in non-windowed mode. To select non-windowed mode, add
the option -nw to the command line.<p>

<pre>
	% mips-lsi-elf-gdb -nw -b 9600 bubble
</pre>

gdb normally expects your monitor to have a prompt of "PMON> " (note
the space). If your monitor uses a different type of prompt you can
either change it in the Monitor using the <a href="c_set.htm">set</a>
command or tell gdb what prompt to expect.  For example,<p>

<pre>
	(gdb) set monitor-prompt IMON> 
</pre>

Note that this command does <i>not</i> expect quotes around the prompt,
but gdb will take the entire string including trailing spaces. So be careful
to type the string exactly.<p>

Next you must specify the target type, and serial port
that will be used to communicated with the target. For example,<p>

<pre>
	(gdb) target lsi /dev/ttyb
</pre>

this specifies that the target is running LSI Logic's PMON (or IMON),
and that the target is connected to /dev/ttyb on the host. If you are
using <a href="dosdef.htm">MSDOS</a> you will need to specify one of
the COM ports. eg. com1.<p>

To download your program to the Target issue the "load" command. No
arguments are necessary as gdb has all the other information it needs.<p>

<pre>
	(gdb) load
</pre>

If you simply want to run your program, you can just type "run". But if
as is more likely you want to be able to set breakpoints and single-step
your program, you should type,<p>

<pre>
	(gdb) b main
	(gdb) run
</pre>

this will set a breakpoint at "main" and execute the program until it
reaches that point.<p>

The following table is a summary of the most frequently used commands:<p>

<center>
<table border cellpadding=6 width=80%>
<tr><th colspan=3>Brief Command Summary</th></tr>
<tr><th>gdb</th><th>PMON/IMON equivalent</th><th>Description</th></tr>
<tr><td>step</td><td>t</td><td>Single Step</td></tr>
<tr><td>next</td><td>to</td><td>Step Over</td></tr>
<tr><td>b addr</td><td>b addr</td><td>Set Breakpoint</td></tr>
<tr><td>delete</td><td>db *</td><td>Delete</td></tr>
<tr><td>c</td><td>c</td><td>Continue</td></tr>
<tr><td>run</td><td>g</td><td>Start Execution</td></tr>
</table></center><p>

When debugging the Host-to-Target communications it is sometimes useful
to create of log of all the transactions. The following command writes
a log to the file "remote.log".<p>

<pre>
	(gdb) set remotelogfile remote.log
</pre>


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