From: "John S. Fine" <johnfine AT erols DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: ASM - function: what should be pushed?
Date: Tue, 02 Feb 1999 15:45:47 -0500
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

DJ Delorie wrote:

> OK, here it is from the horse's mouth (the gcc/libc sources).  Let me
> know if I missed any.
> 
> ax,cx,dx,sp,st0-7,sw,cw - can be used without saving

  sp?  Well we all know esp is its own special case and
its behavior in standard "C" calling conventions is
clear.  I find it strange that you would class it with
ax,cx,dx.

> bx,si,di,bp - must be preserved
> cs,ds,es,ss - must be preserved
> ip - you don't much choice about this one

> fs - reserved for application use; neither gcc nor libc use this
> gs - used by libc, but need not be preserved if you change it

  "used by libc":  Used and preserved?  or Used and not preserved?
(either way I understand you are saying an ASM called by C code
doesn't need to preserve it;  But it makes a difference).
-- 
http://www.erols.com/johnfine/
http://www.geocities.com/SiliconValley/Peaks/8600/