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Subject: Re: questions about dynamically updating attackboards

Author: Andrew Williams

Date: 16:02:53 08/23/03

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On August 23, 2003 at 18:49:39, Sune Fischer wrote:

>On August 23, 2003 at 18:19:11, Andrew Williams wrote:
>
>Hmm, maybe I wasn't clear, it's been a while since I looked at this stuff :)
>
>As an example:
>
>A rook moves from square "f" to square "t", and captures a knight on "t".
>Vi find the rook's index and the knight's index and add them to the list:
>affected = 1<<(ix_sq[f]) | 1<<(ix_sq[t]);
>All sliders attacking f and t also needs updating (with some exceptions you can
>figure):
>affected |= sliders&(attack_sq[f]|attack_sq[t])
>
>of course sliders here are (ix_pc[BISHOP]|ix_pc[ROOK]|ix_pc[QUEEN])
>
>So now you know what pieces needs their attack boards updated, and you take one
>piece of a time finding the bits that have changed and mask them out.
>
>Maybe it is better to use another squares table instead of indexes, I never
>could decide on that.
>
>-S.

Yes. I'm sure I'll get round to changing mine eventually to compare. Meantime,
I've got a million other issues to sort out in PM...

Andrew



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