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SubjectRe: [Q] Implementation of spin_lock on i386: why "rep;nop" ?
Followup to:  <>
By author: Alan Cox <>
In newsgroup:
> > 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.

Now, the example brought up was assembly, but in general I really
think we should have a processor-independent wait_loop(); inline.
Right now we have a rep_nop(); inline which only works on x86 (and
presumably x86-64).

<> at work, <> in private!
"Unix gives you enough rope to shoot yourself in the foot." <>
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