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Subject: Re: Integer vs. Floating Point

Author: Roy Eassa

Date: 06:18:12 12/08/00

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On December 08, 2000 at 05:57:37, Vincent Diepeveen wrote:

>On December 07, 2000 at 15:20:02, Roy Eassa wrote:
>
>>But what impact, if any, does floating point have on such chess apps as Crafty,
>>Chess Tiger, Fritz, Junior, Hiarcs, Shredder, et. al.?  (E.g., which would help
>>them more: a 50% boost in integer speed only, or a 200% boost in floating speed
>>only?)
>
>First of all you need to be completely assembly to make usage of
>floating point. secondly what INSTRUCTIONS from FPU do you plan
>to use?
>
>I guess doing everything in FPU in C would slow down a
>program 4 times or so?
>
>Just keeping hashing in the FPU casted to MMX is of course a
>possibility. That would be the only possible usage of MMX/FPU as
>far as i can see.
>
>But does 0.5% speedup makeup for rewriting your entire program?

<snip>

Didn't mean to imply that I'm writing a program.  No time to do that.

I was just curious what attributes/benchmarks of a CPU most closely correspond
to increased chess program strength.  I use computers based on both PowerPC and
x86, and know that PowerPC is (much) better at a given MHz for floating point
(as I recall).  But I think x86 holds its own at integer, and is of course
available in much higher MHz (1200 [even 1500 for P4] versus 500 [soon 700?] for
PPC-G4).  For Photoshop (etc.), the PPC is generally faster, even at the lower
MHz.  But I now have confirmed what I suspected -- an identical algorithm for
chess would likely play stronger on a 1.2 GHz Athlon than a 700 MHz PPC-G4.



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