Message-Id: <m10BKiA-000S6EC@inti.gov.ar>
Comments: Authenticated sender is <salvador AT natacha DOT inti DOT gov DOT ar>
From: "Salvador Eduardo Tropea (SET)" <salvador AT inti DOT gov DOT ar>
Organization: INTI
To: Paul Derbyshire <pderbysh AT usa DOT net>, djgpp AT delorie DOT com
Date: Fri, 12 Feb 1999 12:44:04 +0000
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Subject: Re: Asm question
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Reply-To: djgpp AT delorie DOT com

Paul Derbyshire <pderbysh AT usa DOT net> wrote:

> I notice gcc zeroes eax using
> 
> 
> xorl  %eax, %eax
> 
> rather than
> 
> movl  $0, %eax
> 
> Is the xorl faster or more pipelinable or something? Seems
> counterintuitive. :-)

Needs less bytes, movl needs the 32 bits for the 0 plus the opcode.

SET 
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