Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!princeton!orsvax1!pyrnj!caip!seismo!mcvax!vmucnam!axis!alastair
From: alastair@axis.UUCP (Alastair Adamson)
Newsgroups: net.micro.pc
Subject: DOS Fatal Error Handling
Message-ID: <500@axis.UUCP>
Date: Thu, 20-Mar-86 10:38:28 EST
Article-I.D.: axis.500
Posted: Thu Mar 20 10:38:28 1986
Date-Received: Sat, 22-Mar-86 23:17:32 EST
Reply-To: alastair@axis.UUCP (Alastair Adamson)
Organization: Axis Digital, 135 rue d'Aguesseau, Boulogne, 92100, FRANCE
Lines: 17

I'm having lots of trouble trying to handle DOS fatal errors.
I've written a routine in assembler and initialised the
interrupt vector with its address (interrupt 24H). The routine
gets called ok but either the program screws up a bit later
or completely hangs. In the routine, I just restore all the user
registers from the stack and do an "iret" with just the ip, cs
and flags (from when I called bios) left on the stack. I also
try saving the error id (from di) in a program global variable
(after having restored ds) and this seems to get set ok.
Alternatively, I have also tried just saving di in a variable
carefully placed in the code segment, setting al to 0 and
doing an iret to let dos handle the stack. The results are
equally disasterous.

I would greatly appreciate any hints, help or other wisdom
on the subject. Thanks in advance (and I will also personally
thank any responders afterwards!).