Author: Larry Griffiths
Date: 13:22:42 01/23/01
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On January 23, 2001 at 15:46:08, Dann Corbit wrote: >On January 23, 2001 at 14:41:28, Severi Salminen wrote: > >>>I created a GenerateCapturesMoves styled after your Crafty GenMove. >> >>What was your previous movegen like? I have not yet watched Crafty's movegen so >>what modifications did you make to improve your speed? I have also spent a lot >>time speeding my movegen up and now I'm sometimes faster that Crafty and >>sometimes not. >> >> >>>Looks like it is worth about 100,000 moves per second in my program. >>>I do not update hashkeys like your perft does. >>>I may be able to get a few more moves per second with some tweaking. >> >>Indeed you can, but be sure _not_ to make performance comparisons based to perft >>or perf only. In normal search you should generate 10x (or more)the moves you >>actually make. So if you make modifications that slow your movemakeing down and >>speed your movegen up you might get different results in search and perft. Perft >>will probably indicate that you are slower but in reality you are faster. And a >>better result in perft might mean worse result in search... :( > >Do you use 0x88? > >I am experimenting with using a common internal format that is easily translated >into other formats. I change from bitmaps to 0x88 when the board is dense or >sparse. I am using MMX registers in my program (64-bit :) as they seem to significantly increase performance when working with bitboards. I also re-designed my diagonal bitboards so that pairs of diagonals fit within a byte. I replaced the SHIFT/AND with... _ESI = (unsigned long)fsq;\ asm lea EDI,bbArray1;\ asm movzx EAX,bbRankContentsOffset[ESI];\ asm movzx EBX,bbFileContentsOffset[ESI];\ asm movzx ECX,bbLDiagContentsOffset[ESI];\ asm movzx EDX,bbRDiagContentsOffset[ESI];\ asm movzx EAX,byte ptr [EDI+EAX+bbRankOccupied*8];\ asm movzx EBX,byte ptr [EDI+EBX+bbFileOccupied*8];\ asm movzx ECX,byte ptr [EDI+ECX+bbLDiagOccupied*8];\ asm movzx EDX,byte ptr [EDI+EDX+bbRDiagOccupied*8];\ which finds the byte offset in the bitboard using the square number, then loads the contents of a diagonal into a register using the byte offset. This seems to have produced a slight increase in performance.
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