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Date: Sun, 28 Dec 2003 23:30:10 +0200
From: "Eli Zaretskii" <eliz AT elta DOT co DOT il>
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To: djgpp AT delorie DOT com
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	(bam AT SNIP_nightstorm_SNIP DOT com)
Subject: Re: How to hook into an exception handler?
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> From: "Bruce A. Mallett" <bam AT SNIP_nightstorm_SNIP DOT com>
> Newsgroups: comp.os.msdos.djgpp
> Date: Sun, 28 Dec 2003 18:31:14 GMT
> 
> I've been trying to figure out how to fill in the exceptionHandler() in 
> i386-stub.c so that I can do remote serial debug w/ gdb to MSDOS.  I've 
> seen a few articles by searching the archives, one referring to calling 
> debug support functions aka go32-nat.c
> 
> But I still don't get it.  I see how to hook into interupt vectors 
> documented in the FAQ.  Is the same mechanics used for exceptions?

It's similar, see the functions
__dpmi_get_processor_exception_handler_vector and
__dpmi_set_processor_exception_handler_vector (documented in the
library docs).  However, you don't need that: DJGPP already has debug
support functions that will do all that and more for you.  You should
simply write a replacement for i386-stub.c that uses those functions.

> Is there some something I can read that will help me?

Start by reading about the debug support functions in the libc docs.
Like this:

     info libc functional debug

The most important functions are v2loadimage and run_child.  You can
use the code in go32-nat.c as your guide; the function go32_wait is
where to start.

Good luck!