Messages in this thread |  | | Subject | Re: [Q] Implementation of spin_lock on i386: why "rep;nop" ? | Date | Mon, 17 Sep 2001 18:27:44 +0100 (BST) | From | Alan Cox <> |
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> The "rep;nop" line looks dubious, since the IA-32 programmer's manual from > Intel (year 2001) mentions that the behaviour of REP is undefined when it > is not used with string opcodes. BTW, according to the same manual, REP is > supposed to modify ecx, but it looks like is is not the case here... which > is fortunate, since ecx is never saved. :-)
rep nop is a pentium IV operation. Its retroactively after testing defined to be portable and ok.
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