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Subject: Bitboards and Piece Lists

Author: Dann Corbit

Date: 16:34:09 06/14/01


Using this "darn-fast" branchless first-bit location routine:
int FirstPiece(BITBOARD bits)
{
//    if (bits == 0) return -1;
__asm {
;       64-bit number to move into ECX:EBX, will never be zero!
        mov ecx,dword ptr [bits+4]
        mov ebx,dword ptr [bits]
        bsf eax,ecx
        add eax,32
        bsf eax,ebx
      }
}

I would think that iterating over the board would be just as fast (or possibly
faster) than using piece lists.

I am curious if others who use bitboards find piece lists to be valuable.
I am somewhat surprised to see that FirstPiece() is consuming a lot of CPU.




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