Re: Semaphore assembly-code bug

[Andreas Steinmetz]

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@xxxxxxxx
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