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Subject: Re: to rotate or not?

Author: Dan Newman

Date: 02:45:51 04/25/00

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On April 25, 2000 at 05:12:36, Bas Hamstra wrote:

>On April 25, 2000 at 01:32:48, Tom Kerrigan wrote:
>
>>On April 25, 2000 at 01:20:11, Bas Hamstra wrote:
>>
>>>(Currently I myself have started all over trying to make a really fast rotated
>>>BB program. Looks promising so far: make/unmake=2M/sec and movegeneration=12M
>>>moves/sec on a Celeron 466)
>>
>>My program does gen/make/unmake at 2M/sec, and just gen at ~10M/sec.
>>
>>I'm not using any sort of bitboards.
>>
>>Maybe something to consider...
>>
>>-Tom
>
>I have them all, including 0x88. I don't think I have squeezed every bit of
>speed out of my quick 0x88 version, but it was slower than my current bitboard
>version especially for generating only captures (which is more important than
>the "moves generated/sec" statistic in my opinion).
>
>Basically I can do around 850k times/sec a GenerateCaptures(). I didn't manage
>that with 0x88.
>
>
>Regards,
>Bas Hamstra.

I, too, find that bitboards are somewhat faster than 0x88, but not enough
faster that that should be a prime consideration (it's what first sold
me though...).  What I really like is that bitboards eliminated two things
that I didn't like in my 0x88 programs:

    1) 0x88 board coordinates, which, if used in the "raw" form, tended
    to bloat up arrays (like the history heuristic table).  Re-mapping
    0x88 coords to 64-square coords costs a bit.

    2) The piece list--which was always a bother.

-Dan.



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