Message-ID:	<32A373A3.6C6@ananke.amu.edu.pl>
Date:	Tue, 03 Dec 1996 01:26:11 +0100
From:	Mark Habersack <grendel AT ananke DOT amu DOT edu DOT pl>
Reply-To:	grendel AT ananke DOT amu DOT edu DOT pl
Organization:	Home, sweet home
MIME-Version:	1.0
To:	sandmann AT clio DOT rice DOT edu
CC:	djgpp AT delorie DOT com
Subject:	Re: Problem raising exceptions in tight loops
References:	<849468187 DOT 25048 DOT 0 AT abwillms DOT demon DOT co DOT uk> <32a21f73 DOT sandmann AT clio DOT rice DOT edu>

Charles Sandmann wrote:
 
> No, no, no.  In a hardware interrupt you have no information about the state
> of the DJGPP program or any way to change it.  So you don't know the EIP (if
> you did, you could use lots of tricks to transfer control) and making
> the app CS illegal will puke the DPMI.  You have to be very careful messing
> with the app DS also - which is why the DS alias exists.
I was thinking about using a TSS as a source of information about
CS:EIP. Wouldn't it be possible to store a pointer to the last tasks's
TSS in some place accessible for the HW handler, and then take all the
data you need from the TSS? In a non-multitasking environment like DOS
it should be quite possible.

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