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SubjectRe: Semaphore assembly-code bug
Linus Torvalds wrote:
> Somebody should check what the Pentium M does. It might just notice that
> "lea 4(%esp),%esp" is the same as "add 4 to esp", but it's entirely
> possible that lea will confuse its stack engine logic and cause
> stack-related address generation stalls..

Now especially Intel tells everybody in their Pentium Optimization
manuals to *use* lea whereever possible as this operation doesn't depend
on the ALU and is processed in other parts of the CPU.

Sample quote from said manual (P/N 248966-05):
"Use the lea instruction and the full range of addressing modes to do
address calculation"

I would guess Intel would add caveats about such stalls in this manual
if there would be any.
--
Andreas Steinmetz SPAMmers use robotrap@domdv.de
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