Date:	Tue, 25 May 1999 10:52:06 +0300 (IDT)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	pavenis AT lanet DOT lv
cc:	djgpp-workers AT delorie DOT com
Subject:	Re: gdb 4.18 for DJGPP (alpha)
In-Reply-To:	<B0000087976@stargate.astr.lu.lv>
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Reply-To:	djgpp-workers AT delorie DOT com
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On Mon, 24 May 1999 pavenis AT lanet DOT lv wrote:

> It appears that I was wrong. The problem is with hardware assisted 
> breakpoints (hbreak).

I didn't try hbreak yet.  I will see whether I can reproduce this
problem tonight.

> First expression is that translation from interrupt to exception 
> (src/libc/go32/exceptn.S) fails for SIGTRAP when running under 
> debugger.

The only change in exceptn.S was that, if it finds SS to be the DS
alias selector, it puts the normal DS into the stack frame popped on
return from exception, in effect forcing the stack to use the normal
DS/SS selector once C code is running again.

I don't know whether this can affect the debug support, but it should
be easy to take this change out, rebuild GDB and see if the problem
goes away.  I can send you the diffs (which you will need to apply
with "patch --reverse"), if you want.

> I tested earlier binaries I had:
> 	5th Jaunary binary of gdb-4.17 (at that time there were rather 	
> 	active work with dbgcom.c by Pierre and me). That binary 
> 	seems  to get hardware breakpoint as required.

Did that 4.17 binary use the current libc.a?  If not, perhaps you
could rebuild that 4.17 binary with the current libraries and see if
the problem is in GDB changes or in DJGPP changes.

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