Xref:	news2.mv.net comp.os.msdos.djgpp:3617
From:	nicolas AT dsys DOT ceng DOT cea DOT fr (Eric NICOLAS)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: mov %eax, %eax in generated asm source
Date:	9 May 1996 06:43:09 GMT
Organization:	Commissariat a l'energie atomique, Grenoble (France)
Lines:	22
Message-ID:	<4ms45t$8jv@news.cea.fr>
References:	<4mnhbv$qs2 AT doc DOT zippo DOT com>
Reply-To:	nicolas AT dsys DOT ceng DOT cea DOT fr
NNTP-Posting-Host:	hudson.ceng.cea.fr
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

>Can anyone tell me the purpose of the code that is generated by
>gcc -S fred.c
>
>whereby it generates
>
>mov %eax, %eax
>
>???? It seems like a time-waster to me ??

I *think* this is one of the most efficient way for testing if %eax is 
zero without modifying it. the other way is "or %eax,%eax".

-- 
Eric Nicolas <nicolas AT dsys DOT ceng DOT cea DOT fr>

Take a look to the SWORD home page :
	france:	http://bunny.ensea.fr/Pages_Perso/Cedric_Joulain/sword.web/home.html
	us:	http://www.iquest.net/~cworley/sword.web/home.html

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