From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <9607151403.AA14089@clio.rice.edu>
Subject: Re: Debuggers under Windows
To: dj AT delorie DOT com (DJ Delorie)
Date: Mon, 15 Jul 1996 09:03:17 -0600 (CDT)
Cc: eliz AT is DOT elta DOT co DOT il, djgpp-workers AT delorie DOT com, terra AT diku DOT dk
In-Reply-To: <199607151214.IAA30793@delorie.com> from "DJ Delorie" at Jul 15, 96 08:14:15 am
Content-Type: text

> > breakpoints, so it seems.  ANY breakpoint that is set by writing the CCh 
> > opcode (Int 03) seems to not work under Windows, in either GDB or FSDB.  
> 
> Did anyone remember to trap interrupt 0x03, or is it still pointing to
> space?

DJGPP does not hook interrupt 0x03, which may be the problem.  Intel does
not differentiate between interrupts and exceptions in the range 0-0x1f
and talks about the breakpoint exception.  The DPMI spec says that 
exceptions not hooked will be then reflected as PM interrupts (which if
not hooked would be passed to RM...).  

One thing to note before unhooking exception 0x3 and hooking interrupt 0x3
is that I don't know if CWSDPMI will handle this properly.  Beware -
not tested.  If we need a CWSDPMI fix, I'll put it in R3.