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Subject: Re: regular hash key & pawn hash key together--good idea?

Author: Robert Hyatt

Date: 17:24:45 09/16/99

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On September 16, 1999 at 12:38:41, Andrew Dados wrote:

>On September 16, 1999 at 12:19:24, Tom Kerrigan wrote:
>
>>The overhead of separating 24 bits is trivial:
>>
>>(hash_key >> 40)
>>
>>-Tom
>
> Well.. you have to detect pawn moves/captures exactly as in 'normal, 2-key
>way', separate that, xor, mask topmost bits and finally combine back. No real
>gain when you think of that. (otherwise xor would screw both 'parts' of key).
>But that of course only for xor way...
> -Andrew-


You probably wouldn't have to do this...  you would just put bits in the right
part of each of the random numbers you xor in/out.  IE pawns only have bits on
the right end, pieces only on the left.. then you would ignore which is which.

However, on a PC, if I did this, I would just do two 32 bit values separately
to avoid the overhead...



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