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

Author: Tom Kerrigan

Date: 09:19:24 09/16/99

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The overhead of separating 24 bits is trivial:

(hash_key >> 40)

-Tom

On September 16, 1999 at 12:10:24, Andrew Dados wrote:

>On September 16, 1999 at 04:00:43, Tom Kerrigan wrote:
>
>>If you have a program with 64 bit hash keys, is it a good idea to devote n bits
>>to pawns and the rest to pieces and side-to-move?
>>
>>I was thinking a good balance may be 24 bits for pawns, but I have no data to
>>back this up. Does anybody else?
>>
>>-Tom
>
> This is one cool idea to consider especially while our nps goes up a bit every
>year... At one point 64 bit hash will not be sufficient, so then 64 bit piece
>and 32 bit pawn signature would work great. However for now, if your hashkey
>calculation is incremental and involves xor function, overhead of separating 24
>bits from it is quite comparable to calculating second pawn hashkey, I think
>(saving of some 10-20 clock ticks is simply not worth the headache).
>
> -Andrew-



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