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Subject: Re: Bitboard question

Author: Vincent Diepeveen

Date: 06:45:25 07/07/03

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On July 07, 2003 at 09:21:17, Jarkko Pesonen wrote:

Keep in memory a bitboard that doesn't go from

a1 to h1 then from a2 to h2 etc till h8.

But use a bitboard that goes for example like

a1 .. a8,b1..b8 etc.

bitboard is like
0x0008080040020800
then

then a simple firstone and lastone solves your problem.

Best regards,
Vincent


>In Crafty bitboard function FirstOne gives 12 and LastOne gives 53.
>Is there fast implementation for LeftOne and RightOne, which
>would give in below case 33 and 38.
>C implementation would ne appriciated.
>
>---+---+---+---+---+---+---+---+
>   |   |   |   |   |   |   |   |
>---+---+---+---+---+---+---+---+
>   |   |   |   |   | *P|   |   |
>---+---+---+---+---+---+---+---+
>   |   |   |   |   |   |   |   |
>---+---+---+---+---+---+---+---+
>   | *P| *P|   |   |   | *P|   |
>---+---+---+---+---+---+---+---+   0x0080000062000400
>   |   |   |   |   |   |   |   |
>---+---+---+---+---+---+---+---+
>   |   |   |   |   |   |   |   |
>---+---+---+---+---+---+---+---+
>   |   |   |   |*P |   |   |   |
>---+---+---+---+---+---+---+---+
>   |   |   |   |   |   |   |   |
>---+---+---+---+---+---+---+---+
>
>thanks in advance
>
>Jarkko



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