From:	eplmst AT lu DOT erisoft DOT se (Martin Stromberg)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: inline assembly syntax for accessing variables ?
Date:	20 Dec 2002 08:34:23 GMT
Organization:	Ericsson Erisoft AB, Sweden
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Lars O. Hansen (lars DOT o DOT hansen AT gmx DOT de) wrote:
: Or is using XCHG for variable swapping instead of direct translation of
: int tmp;
: tmp=a;
: a=b;
: b=tmp;
: part of djgpps optimization routines?

Why don't you "gcc -Wall -O2 -S tst.c" and check the assembly. Then
try with "-O3" and even higher if your version of gcc supports them.

: Or is XCHG a "mnemonic macro" itself or are there reasons not to use XCHG or pay speacial attention
: to sth. when using it?

It's a proper CPU instruction on IA32. There might be locking issues.


Right,

						MartinS

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