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Subject: Re: Pentium 4 and 2.4/2.5
To: bapper@piratehaven.org (Brian Pomerantz)
Date: Wed, 8 Nov 2000 18:21:54 +0000 (GMT)
Cc: torvalds@transmeta.com (Linus Torvalds),
        alan@lxorguk.ukuu.org.uk (Alan Cox), linux-kernel@vger.kernel.org
In-Reply-To: <20001108101248.A8902@skull.piratehaven.org> from "Brian Pomerantz" at Nov 08, 2000 10:12:48 AM
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> > 		asm volatile("rep ; nop");
> > 
> > (there's not much a "rep nop" _can_ do, after all - the most likely CPU
> > extension would be to raise an "Illegal Opcode" fault).
> 
> Just for the curious, this works on Athlons. :)

What state does it leave the condition codes ?  That matters. 

Take for example

if (!oldval)
                asm volatile(
                        "2:"
                        "cmpl $-1, %0;"
                        "rep; nop;"
                        "je 2b;"
                        	: :"m" (current->need_resched));
}

When running SMP with poll_idle enabled. I can't see it changing condition
codes on an athlon but..

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