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Mail Archives: djgpp/2009/05/04/07:08:34

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Date: Mon, 04 May 2009 14:07:42 +0300
From: Eli Zaretskii <eliz AT gnu DOT org>
Subject: Re: Please help resurrecting GDB for version 7.0 release
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> From: Rugxulo <rugxulo AT gmail DOT com>
> Date: Sun, 3 May 2009 17:23:31 -0700 (PDT)
>=20
> > But needing to debug is another issue, agreed. =A0There
> > are the complications of determining support, etc, making sure yo=
u don't
> > break old platforms. =A0Not worth the hassle.
> > (For someone wanting to work on this, the referenced code is in d=
bgcom.c).
>=20
> Lots of inline AT&T in that file. Very confusing although I
> (unsurprisingly) admit to knowing nothing about the FPU and DPMI
> exceptions.

This is unrelated to DPMI exceptions.  It is simply a matter with wha=
t
instructions to use to save and restore the FPU state when jumping
between the debugger and the debuggee (since they both run in the sam=
e
process on DOS).

I really don't see any sense in modifying the library unless there's
going to be a release of v2.04 soon.  As Charles points out, adding
SSE support will need code added to determine whether FXSAVE/FXRSTOR
are supported before we use them, and a lot of testing to make sure w=
e
don't break old machines.

OTOH, if someone needs it badly on a machine that is known to support
these instructions, they can simply replace FNSAVE/FRSTOR with the
extended instructions, modify the definition of the NPX object in
debug/dbgcom.h to accommodate for the extra registers, and be done.

> Maybe somebody can find Pierre Muller and bug him to work
> on it (doubtful).

Pierre is very active on the GDB forum, so he is easy to find.  But I
don't think he wrote the code in question.

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