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Date:      Sat, 7 Feb 1998 23:37:37 -0600 (CST)
From:      Damon Permezel <dap@damon.com>
To:        nate@mt.sri.com (Nate Williams)
Cc:        dap@damon.com, hackers@FreeBSD.ORG
Subject:   Re: MMX, pentium, etc
Message-ID:  <199802080537.XAA10571@damon.com>
In-Reply-To: <199802080517.WAA17659@mt.sri.com> from Nate Williams at "Feb 7, 98 10:17:33 pm"

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"Nate Williams sez: "
> > I have a Java app which uses some intensive FP, for which I have
> > written native (aka: C) routines to accelerate.
> > 
> > I am getting to the point where I am once again tapped out, so I want
> > to explore hand coded MMX instructions in my (unrolled, hand optimized)
> > inner loops.
> 
> Umm, if you're using the FPU, then MMX would be a lose if you mix FPU
> and MMX instructions.  Better to stick with just FPU instructions.

Well, I'll make that decision when I know what the MMX instructions are.

All I know is, MMX are supposed to be for multimedia, and in particular enable
full-screen s/w mpeg.  A lot of what I do is inverse DCT, except I go
256x256, rather than 8x8.  I will probably change to an integer iDCT
when I am able to see what the MMX instructions are: ie if they are all
integer instructions.

I suppose I should change to integer anyway, but I have been spoiled by
working on machines which had decent FP performance.

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