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Subject: Re: Reversed vs. Rotated Bitboards

Author: Sune Fischer

Date: 10:34:55 01/28/02

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On January 28, 2002 at 13:21:21, Vincent Diepeveen wrote:

>>I don't understand his MMX idea, I think it's just to increase speed in 64-bit
>>operations, I don't see why they should be needed here. We don't need to
>>re-reverse the bitboards, they are incrementally constructed.
>>
>>I've made my little rook attack algorithm here on paper, it is about 20 64-bit
>>operations in total - no table lookups and no if's or while's!
>
>then your mobility concept sucks from chessknowledge quality viewpoint.
>No mobility is better than stupid mobility say some programmers, though
>i disagree here partly it sure has some truths in it.

LOL, you can always make me smile ;)
When did the mobility enter the picture?
For mobility I just count the bits on the attack boards, what else is there to
do? Mobility is like 50% of my eval() just after material, could not do without
it.
The problem at hand is to _get_ the attack boards, not how to _use_ them
afterwards.


>>Think of the potential speed increase when we get 64-bit chips, the rotated
>>bitboards will still be handicaped by the table lookups.
>
>I still couldn't buy a 64 bits processor cheap that outguns a dual K7
>system and right now i don't see how to make it either.

Get used to thinking 64-bit, only a few more years and they will be here!
It will be a nice boost for a lot of people, while the rest will be busy trying
to figure out what hit them.

>>Anyway, I'll write down the algorithm now and post it here, then you can tell me
>>if it will stand a chance against rotated ;)
>
>for generating moves from - to for bishops and rooks, that sure is
>appreciated.
>
>>I hope there are no mistakes, I haven't tested it.
>

It is done.



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