Date: Wed, 17 Jan 1996 18:00:58 +0000 (GMT)
From: Dominic Hibbs <mtx064 AT coventry DOT ac DOT uk>
To: djgpp maillist <djgpp AT delorie DOT com>
Subject: MSDOS damages extended registers
Message-ID: <Pine.OSF.3.91.960117175457.32005B-100000@leofric>
MIME-Version: 1.0

I have just discovered that calls to int0x21 clears the high sixteen bits 
of many of the extended registers.  It seems that the only ones which are 
not affected are ebp, esp and eip.

Last time I sent this message it failed to get through - see what happens 
this time.

Dominic

P.S. I have a modified version of edebug32 which disassembles to the same 
mnemonics as AS accepts. - if anyone wants it and the changed sources 
debug.c and unassmbl.c  
and also a pre-preprocessor that solves most of the problems of 
incompatibility between GASP (good name that!) and AS.

Dominic