On 2013-02-19 13:20, David Shwatrz wrote:
> We have:
> #define cpu_relax() asm volatile("rep; nop")
> in arch/x86/boot/boot.h.
>
> Why don't we use the PAUSE assembler instruction here ?
If you dig further into the Intel x86 manual, the machine instructions
'pause' and 'rep;nop' actually use the exact same encoding. As some
older assembler might not know the 'pause' mnemonic, using 'rep;nop'
here is most probably for backwards compatibility.
Rainer
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