Re: [PATCH] change name of rep_nop

Alan Cox (alan@lxorguk.ukuu.org.uk)
Tue, 9 Oct 2001 12:30:39 +0100 (BST)


> 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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