PAUSE
Usage: PAUSE Modifies flags: None
Improves the performance of spin-wait loops. When executing a 'spin-wait loop,' a Pentium 4 or Intel Xeon processor suffers a severe performance penalty when exiting the loop because it detects a possible memory order violation. Spin Loop Hint
PAUSE ; F3 90 [WILLAMETTE,SSE2]
PAUSE provides a hint to the processor that the following code is a spin loop. This improves processor performance by bypassing possible memory order violations. On older processors, this instruction operates as a NOP.
The processor uses this hint to avoid the memory order violation in most situations, which greatly improves processor performance. For this reason, it is recommended that a PAUSE instruction be placed in all spin-wait loops.
EXAMPLE:
pause