From: "Christian Merz" <cmerz AT bndlg DOT de>
Newsgroups: comp.os.msdos.djgpp
References: <3b66ad7a$0$414$7d5a4a58 AT news DOT compuserve DOT de> <200107311334 DOT JAA15874 AT envy DOT delorie DOT com>
Subject: Re: ds==ss why?
Date: Tue, 31 Jul 2001 18:12:09 +0200
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

i don't need more than 4gb address space but i would like to setup a common
stack frame for the system-level code. for example i have 64kb somewhere in
the 4 gb address space. so i setting up a new selector with the linear base
address of the 64kb stack frame and esp & limit is 64kb. that's my problem.
to avoid this problem, i have only one "bad" possibility. leaving the linear
base address of ss and set the esp to ss+new stack frame address, but this
will only work for esp>linear base address of ss. i think this is no good
solution for me, because push instruction could overwrite some code or data
if the stack frame has not enough room esp<start address of stack frame
(underrun).

chris

"DJ Delorie" <dj AT delorie DOT com> schrieb im Newsbeitrag
news:200107311334 DOT JAA15874 AT envy DOT delorie DOT com...
>
> > can I change the behavior of gcc concerning that ds==ss?
>
> GCC really expects SS==DS (and, in djgpp, CS==DS also).  Why do you
> need more than 4Gb of address space anyway?