Subject: Re: [linux-audio-dev] real-life 3dnow! results
From: est_AT_hyperreal.org
Date: la elo 28 1999 - 01:59:31 EDT
I'm continuing in my grand tradition of replying to myself. :)
I looked at Intel's online mmx manual and found an instruction that
cleans up my code a lot. It doesn't seem to speed things up much, but
it *does* add clipping. It also makes other code optimizations easier.
Simply replace the following code chunk (which appears twice):
> movq %mm1,(%esp)
> movw (%esp),%ebx
> movw %ebx,(%ebp)
> movw 4(%esp),%ebx
> movw %ebx,2(%ebp)
with:
packssdw %mm1,%mm1
movd %mm1,(%ebp)
The scratch space on the stack is no longer needed.
Eric
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