Author: Michel Langeveld
Date: 01:34:03 12/11/04
Go up one level in this thread
To probe a tablebase you need to setup some arrays.
You need to fill the following array:
int rgiCounters[10] = {0,0,0,0,0,0,0,0,0,0};
This arrays contains of each piecetype the number.
Fill it as follows:
// white:
// rgiCounters[0] == number of pawns
// rgiCounters[1] == number of knights
// rgiCounters[2] == number of bishops
// rgiCounters[3] == number of rooks
// rgiCounters[4] == number of queens
// black:
// rgiCounters[5] == number of pawns
// rgiCounters[6] == number of knights
// rgiCounters[7] == number of bishops
// rgiCounters[8] == number of rooks
// rgiCounters[9] == number of queens
This is doable, isn't it?
Then you need to setup the arrays W, and B as follows:
squaret W[C_PIECES * 5 + 1];
squaret B[C_PIECES * 5 + 1];
// piecetypes (1 .. 5): fieldtypes (0 to 63):
// 0 == PAWN A1(0), A2(1) ... A8(7)
// 1 == KNIGHT B1(8) ...........B8(15)
// 2 == BISHOP ...................
// 3 == ROOK ...................
// 4 == QUEEN .................H8(63)
// 5 == KING
//
// W[0] = 1st pawn W[1] 2nd pawn W[2] 3rd pawn
// W[3] = 1st knight W[4] 2nd knight W[5] 3rd knight
// W[6] = 1st bishop W[7] 2nd bishop W[8] 3rd bishop
// W[9] = 1st rook W[10] 2nd rook W[11] 3rd rook
// W[12] = 1st queen W[13] 2nd queen W[14] 3rd queen
// W[15] = contains always white king
Also doable, isn't it?
If this is doable ... then you are over 50%!
You need also an enpassant field as follows:
if (p.epField == INVAL_FIELD)
sqEnP = 127; //ep field
else
sqEnP = field2idx64(p.epField
If you get this ... then you are almost there.
The namilov tables are so that white is always the won with more pieces as
black. So then you need to do:
//If black is the "winning" side (more pieces) then we need
//to "invert" the pieces in the lists.
if (iTb > 0) {
if ( p.moveColor == WHITE ) side = 0; else side = 1;
fInvert = 0;
psqW = W;
psqB = B;
}
else {
if ( p.moveColor == WHITE ) side = 1; else side = 0;
fInvert = 1;
psqW = B;
psqB = W;
iTb = -iTb;
}
Then you are ready to probe the tablebases....
//now check to see if this particular tablebase for this
//color to move is registered.
if (!FRegistered(iTb, side)) return -1;
ind = PfnIndCalc(iTb, side) (psqW, psqB, sqEnP, fInvert);
//Comment this line out to load all tables in memory?
//FReadTableToMemory (iTb, side, NULL);
//probe the table
tbScore = L_TbtProbeTable (iTb, side, ind);
//if not found
if(tbScore == bev_broken) return -1;
int add = (p.moveColor == BLACK ? 1 : 0);
//now convert to correct MATE range the value
//Nullmover uses
if(tbScore > 0)
return (tbScore-bev_mi1)*2 + 9999 - (ply-1) - add;
if(tbScore < 0)
return (tbScore+bev_mi1)*2 - 9999 + (ply-1) + add;
return 0;
}
Futher more you need some defines, and function defintions:
#define XX 127
#define C_PIECES 3 /* Maximum # of pieces of one color OTB */
#define TB_FASTCALL __fastcall
typedef unsigned __int64 INDEX;
typedef unsigned int squaret;
typedef int color;
#define bev_broken 32767
#define bev_mi1 32766
typedef INDEX(TB_FASTCALL * PfnCalcIndex)
(squaret *, squaret *, squaret, int fInverse);
extern "C"
{
int IDescFindFromCounters(int *);
int FRegisteredFun(int, color);
PfnCalcIndex PfnIndCalcFun(int, color);
int TB_FASTCALL L_TbtProbeTable(int, color, INDEX);
int FTbSetCacheSize(void *, unsigned long);
int IInitializeTb(char *);
}
#define PfnIndCalc PfnIndCalcFun
#define FRegistered FRegisteredFun
void *EGTB_cache = (void*)0;
int EGTB;
Cheers and good luck!
Michel
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