Author: Heiner Marxen
Date: 10:12:40 01/01/02
Go up one level in this thread
On January 01, 2002 at 07:44:31, Vincent Diepeveen wrote:
>On December 31, 2001 at 16:07:43, Scott Gasch wrote:
>
>>On December 31, 2001 at 16:03:36, Scott Gasch wrote:
>>
>>>On December 31, 2001 at 15:57:28, Bruce Moreland wrote:
>>>
>>>>
>>>>How many elements are in "iRanks"? If the answer is 8, there is your bug.
>>>>
>>>>In Pascal, arrays are usually 1..N. In C, they are typically 0..N-1. Your
>>>>asserts indicate that you may be thinking in Pascal.
>>>>
>>>>I have more ideas once you indicate that there are more than 8 things in that
>>>>array.
>>>>
>>>
>>>typedef struct _PAWN_HASH_ENTRY
>>>{
>>>INT64 i64Sig;
>>> short iWhiteValue;
>>> short iBlackValue;
>>> unsigned char iFiles[2][10];
>>> unsigned char iRanks[2][10];
>>> unsigned char iPawnsOnWhiteSquares[2];
>>> unsigned char iUnmovedPawns[2];
>>> unsigned char iRammedPawns[2];
>>> unsigned char iBackwardPawns[2];
>>> unsigned char cPassed[2][10];
>>> unsigned char iPasserInfo[2][10];
>>> unsigned char iPassedCount[2];
>>>#ifdef PARANOID
>>> POSITION pos;
>>>#endif
>>>} PAWN_HASH_ENTRY;
>>
>>Darnit, I have a bad habit of submitting early by pressing [tab][space] by
>>accident when typing code.
>>
>>iFiles and iRanks are arrays with 10 elements -- the 0th and 9th are phantom
>>files so I don't have to check for "off the board" in my code. iFiles is the
>>count of how many pawns are on that file and iRanks is the rank of the most
>>advanced one. If there's no black pawn on a rank, iRanks[BLACK][file] is set to
>>zero for passer detection. Likewise no white pawn on a rank means
>>iRanks[WHITE][file] is set to 9.
>>
>>I'll all ears for other ideas. This is driving me nuts. It has to be some
>>problem in my code but I sure don't see it. I've verified I'm not trashing
>>anything on the stack by writing to a stack array out of bounds -- which might
>>cause whatever address it's trying to load into esi just before the crash to be
>>wrong.
>>
>>Thanks for the ideas.
>>Scott
>
>Hi Scott, 8 bits code is usual faster than 32 bits of course,
>but may audience know from you why you make all datastructure code 8 bits
>here?
>
>Why not make it all 32 bits?
Excuse me for jumping in...
I suspect he wants to have lots of those PAWN_HASH_ENTRY objects, so it is
a good thing to have them 1/4 as large, because now he can have more of them.
Also, generally using more memory will cause more cache misses, and those
cost many cycles. Sometimes the panelty is smaller than the gain, but
sometimes not. I have sometimes had significant slowdowns because of using
some more KB of data (happened to me with the random value arrays for the
zobrist hash).
Cheers,
Heiner
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