Feb. 20, 2013
9:18 p.m.
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