Re: [Clax86list] Re: instruction rescheduler?

On Fri, 6 May 2005 03:18:53 +0000 (UTC)
"randyhyde@xxxxxxxxxxxxx" <spamtrap@xxxxxxxxxx> wrote:

:Maybe your statement is true on the Alpha. It is not true on the x86.

"The one byte NOP, xchg EAX,EAX, has special hardware support. Although it
still consumes a __op and its accompanying resources, the dependence upon
the old value of EAX is removed. Therefore, this __op can be executed at the
earliest possible opportunity, reducing the number of outstanding
instructions. This is the lowest cost NOP possible."

-- Intel Pentium 4 & Xeon Optimization Guide

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