i486 base architecture

Arjan van de Ven arjanv at redhat.com
Mon Nov 29 09:16:35 UTC 2004


On Mon, Nov 29, 2004 at 01:02:46AM -0800, Nicholas Miell wrote:
> On Mon, 2004-11-29 at 09:11 +0100, Arjan van de Ven wrote:
> > for what it's worth... cmov isn't faster on newer (pM/pIV/amd64 level)
> > CPUs than the open coded conditional jump anymore....
> > so there no longer really is a reason to use cmov-only code.
> > 
> 
> CMOVcc will use less space in the instruction cache than the Jcc/MOV
> pair, though.

only sometimes.... since cmov doens't work on all register/memory
combinations extra code might be needed to glue that together...


.... and we're suddenly talking about 0.01% performance ;)




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