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Subject: Re: [PATCH] change name of rep_nop
To: etienne_lorrain@yahoo.fr (=?iso-8859-1?q?Etienne=20Lorrain?=)
Date: Tue, 9 Oct 2001 12:30:39 +0100 (BST)
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <20011009085140.85739.qmail@web11801.mail.yahoo.com> from "=?iso-8859-1?q?Etienne=20Lorrain?=" at Oct 09, 2001 10:51:40 AM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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>   Hello,
> > 	__asm__ __volatile__("rep;nop");
> 
> "The behavior of the REP prefix is undefined when used with non-string
> instructions." page 3-404 of Intel documentation, in "CHAPTER 3,
> INSTRUCTION SET REFERENCE"...
> 
>   How about: __asm__ __volatile__("loop ." : "+c" (nbloop)); ?

rep nop is a magic instruction to powersave momentarily on the Pentium 4.
It happens to be a true nop on the older processors
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