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Subject: Re: ASM/Optimization

Author: Zappa

Date: 10:08:59 12/06/05

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On December 06, 2005 at 01:32:58, Lance Perkins wrote:

>int PawnForwardRotate[] = {8,64-8};
>unsigned __int64 PawnForwardMask[] = {0xffffffffffffff00, 0x00ffffffffffffff};
>
>_rotl64 (bbPawns, PawnForwardRotate[color]) & PawnForwardMask[color];
>
>// pre-cond:
>//    Rax = pawn bb
>//    Rdx = color
>
>mov ecx, DWORD PTR PawnForwardRotate[Rdx*4]
>rol rax, cl
>and rax, QWORD PTR PawnForwardMask[Rdx*8]


Hmm.  That certainly helps a lot.  You could do up to a 16 point shift with no
problems, although there is another instruction.

Just out of curiosity, is this in Thinker?

anthony



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