/* gnuchess.c - C source for GNU CHESS Revision: 1990-04-18 Copyright (C) 1986, 1987, 1988, 1989, 1990 Free Software Foundation, Inc. Copyright (c) 1988, 1989, 1990 John Stanback This file is part of CHESS. CHESS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY. No author or distributor accepts responsibility to anyone for the consequences of using it or for whether it serves any particular purpose or works at all, unless he says so in writing. Refer to the CHESS General Public License for full details. Everyone is granted permission to copy, modify and redistribute CHESS, but only under the conditions described in the CHESS General Public License. A copy of this license is supposed to have been given to you along with CHESS so you can know your rights and responsibilities. It should be in a file named COPYING. Among other things, the copyright notice and this notice must be preserved on all copies. */ #include "gnuchess.h" #include #ifdef MSDOS #include #include #include #define RWA_ACC "r+b" #define WA_ACC "w+b" #else #define RWA_ACC "r+" #define WA_ACC "w+" #include #include #include #endif /* MSDOS */ /* */ extern int abs (int); extern int atoi (const char *); /* */ extern long int time (long int *); /* */ extern void *memset (void *, int, size_t); #define valueP 100 #define valueN 350 #define valueB 355 #define valueR 550 #define valueQ 1100 #define valueK 1200 #define ctlP 0x4000 #define ctlN 0x2800 #define ctlB 0x1800 #define ctlR 0x0400 #define ctlQ 0x0200 #define ctlK 0x0100 #define ctlBQ 0x1200 #define ctlBN 0x0800 #define ctlRQ 0x0600 #define ctlNN 0x2000 #define Patak(c, u) (atak[c][u] > ctlP) #define Anyatak(c, u) (atak[c][u] > 0) #if ttblsz #define truescore 0x0001 #define lowerbound 0x0002 #define upperbound 0x0004 #define kingcastle 0x0008 #define queencastle 0x0010 struct hashval { unsigned long key,bd; }; struct hashentry { unsigned long hashbd; unsigned short mv; unsigned char flags, depth; /* char saves some space */ short score; #ifdef HASHTEST unsigned char bd[32]; #endif /* HASHTEST */ }; #ifdef HASHFILE /* persistent transposition table. The size must be a power of 2. If you change the size, be sure to run gnuchess -t before anything else. */ #define frehash 6 #ifdef MSDOS #define filesz (1 << 11) #else #define filesz (1 << 17) #endif /* MSDOS */ struct fileentry { unsigned char bd[32]; unsigned char f, t, flags, depth, sh, sl; }; /* In a networked enviroment gnuchess might be compiled on different hosts with different random number generators, that is not acceptable if they are going to share the same transposition table. */ unsigned long int next = 1; unsigned int urand (void) { next *= 1103515245; next += 12345; return ((unsigned int) (next >> 16) & 0xFFFF); } void srand (unsigned int seed) { next = seed; } #else #define urand rand #endif /* HASHFILE */ static unsigned long hashkey, hashbd; static struct hashval hashcode[2][7][64]; static struct hashentry huge ttable[2][ttblsz]; #endif /* ttblsz */ static short rpthash[2][256]; FILE *hashfile; struct leaf Tree[2000], *root; short TrPnt[maxdepth]; short PieceList[2][16], PawnCnt[2][8]; #define wking PieceList[white][0] #define bking PieceList[black][0] #define EnemyKing PieceList[c2][0] short castld[2], Mvboard[64]; short svalue[64]; struct flags flag; short opponent, computer, Awindow, Bwindow, dither, INCscore; long ResponseTime, ExtraTime, Level, et, et0, time0, ft; long NodeCnt, ETnodes, EvalNodes, HashCnt, FHashCnt, HashCol; short player, xwndw, rehash; struct GameRec GameList[512]; short Sdepth, GameCnt, Game50, MaxSearchDepth; short epsquare, contempt; struct BookEntry *Book; struct TimeControlRec TimeControl; short TCflag, TCmoves, TCminutes, OperatorTime; const short otherside[3] = {1, 0, 2}; unsigned short hint, PrVar[maxdepth]; static short Pindex[64]; static short PieceCnt[2]; static short c1, c2, *atk1, *atk2, *PC1, *PC2, atak[2][64]; static short mtl[2], pmtl[2], emtl[2], hung[2]; static short FROMsquare, TOsquare, Zscore, zwndw; static short HasKnight[2], HasBishop[2], HasRook[2], HasQueen[2]; static short ChkFlag[maxdepth], CptrFlag[maxdepth], PawnThreat[maxdepth]; static short Pscore[maxdepth], Tscore[maxdepth]; static const short qrook[3] = {0, 56, 0}; static const short krook[3] = {7, 63, 0}; static const short kingP[3] = {4, 60, 0}; static const short rank7[3] = {6, 1, 0}; static const short sweep[8] = {false, false, false, true, true, true, false, false}; static unsigned short killr0[maxdepth], killr1[maxdepth]; static unsigned short killr2[maxdepth], killr3[maxdepth]; static unsigned short PV, Swag0, Swag1, Swag2, Swag3, Swag4; static unsigned char history[8192]; static short Mwpawn[64], Mbpawn[64], Mknight[2][64], Mbishop[2][64]; static short Mking[2][64], Kfield[2][64]; static const short value[7] = {0, valueP, valueN, valueB, valueR, valueQ, valueK}; static const short control[7] = {0, ctlP, ctlN, ctlB, ctlR, ctlQ, ctlK}; static const short PassedPawn0[8] = {0, 60, 80, 120, 200, 360, 600, 800}; static const short PassedPawn1[8] = {0, 30, 40, 60, 100, 180, 300, 800}; static const short PassedPawn2[8] = {0, 15, 25, 35, 50, 90, 140, 800}; static const short PassedPawn3[8] = {0, 5, 10, 15, 20, 30, 140, 800}; static const short ISOLANI[8] = {-12, -16, -20, -24, -24, -20, -16, -12}; static const short BACKWARD[16] = {-6, -10, -15, -21, -28, -28, -28, -28, -28, -28, -28, -28, -28, -28, -28, -28}; static const short BMBLTY[14] = {-2, 0, 2, 4, 6, 8, 10, 12, 13, 14, 15, 16, 16, 16}; static const short RMBLTY[15] = {0, 2, 4, 6, 8, 10, 11, 12, 13, 14, 14, 14, 14, 14, 14}; static const short KTHRT[36] = {0, -8, -20, -36, -52, -68, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80, -80}; static short KNIGHTPOST, KNIGHTSTRONG, BISHOPSTRONG, KATAK; static short PEDRNK2B, PWEAKH, PADVNCM, PADVNCI, PAWNSHIELD, PDOUBLED, PBLOK; static short RHOPN, RHOPNX, KHOPN, KHOPNX, KSFTY; static short ATAKD, HUNGP, HUNGX, KCASTLD, KMOVD, XRAY, PINVAL; static short stage, stage2, Developed[2]; static short PawnBonus, BishopBonus, RookBonus; static const short KingOpening[64] = {0, 0, -4, -10, -10, -4, 0, 0, -4, -4, -8, -12, -12, -8, -4, -4, -12, -16, -20, -20, -20, -20, -16, -12, -16, -20, -24, -24, -24, -24, -20, -16, -16, -20, -24, -24, -24, -24, -20, -16, -12, -16, -20, -20, -20, -20, -16, -12, -4, -4, -8, -12, -12, -8, -4, -4, 0, 0, -4, -10, -10, -4, 0, 0}; static const short KingEnding[64] = {0, 6, 12, 18, 18, 12, 6, 0, 6, 12, 18, 24, 24, 18, 12, 6, 12, 18, 24, 30, 30, 24, 18, 12, 18, 24, 30, 36, 36, 30, 24, 18, 18, 24, 30, 36, 36, 30, 24, 18, 12, 18, 24, 30, 30, 24, 18, 12, 6, 12, 18, 24, 24, 18, 12, 6, 0, 6, 12, 18, 18, 12, 6, 0}; static const short DyingKing[64] = {0, 8, 16, 24, 24, 16, 8, 0, 8, 32, 40, 48, 48, 40, 32, 8, 16, 40, 56, 64, 64, 56, 40, 16, 24, 48, 64, 72, 72, 64, 48, 24, 24, 48, 64, 72, 72, 64, 48, 24, 16, 40, 56, 64, 64, 56, 40, 16, 8, 32, 40, 48, 48, 40, 32, 8, 0, 8, 16, 24, 24, 16, 8, 0}; static const short KBNK[64] = {99, 90, 80, 70, 60, 50, 40, 40, 90, 80, 60, 50, 40, 30, 20, 40, 80, 60, 40, 30, 20, 10, 30, 50, 70, 50, 30, 10, 0, 20, 40, 60, 60, 40, 20, 0, 10, 30, 50, 70, 50, 30, 10, 20, 30, 40, 60, 80, 40, 20, 30, 40, 50, 60, 80, 90, 40, 40, 50, 60, 70, 80, 90, 99}; static const short pknight[64] = {0, 4, 8, 10, 10, 8, 4, 0, 4, 8, 16, 20, 20, 16, 8, 4, 8, 16, 24, 28, 28, 24, 16, 8, 10, 20, 28, 32, 32, 28, 20, 10, 10, 20, 28, 32, 32, 28, 20, 10, 8, 16, 24, 28, 28, 24, 16, 8, 4, 8, 16, 20, 20, 16, 8, 4, 0, 4, 8, 10, 10, 8, 4, 0}; static const short pbishop[64] = {14, 14, 14, 14, 14, 14, 14, 14, 14, 22, 18, 18, 18, 18, 22, 14, 14, 18, 22, 22, 22, 22, 18, 14, 14, 18, 22, 22, 22, 22, 18, 14, 14, 18, 22, 22, 22, 22, 18, 14, 14, 18, 22, 22, 22, 22, 18, 14, 14, 22, 18, 18, 18, 18, 22, 14, 14, 14, 14, 14, 14, 14, 14, 14}; static const short PawnAdvance[64] = {0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 4, 0, 0, 4, 4, 4, 6, 8, 2, 10, 10, 2, 8, 6, 6, 8, 12, 16, 16, 12, 8, 6, 8, 12, 16, 24, 24, 16, 12, 8, 12, 16, 24, 32, 32, 24, 16, 12, 12, 16, 24, 32, 32, 24, 16, 12, 0, 0, 0, 0, 0, 0, 0, 0}; /* .... MOVE GENERATION VARIABLES AND INITIALIZATIONS .... */ #define taxicab(a,b) taxidata[a][b] short distdata[64][64], taxidata[64][64]; static inline void Initialize_dist (void) { register short a, b, d, di; for (a = 0; a < 64; a++) for (b = 0; b < 64; b++) { d = abs (column (a) - column (b)); di = abs (row (a) - row (b)); taxidata[a][b] = d + di; distdata[a][b] = (d > di ? d : di); } } const short Stboard[64] = {rook, knight, bishop, queen, king, bishop, knight, rook, pawn, pawn, pawn, pawn, pawn, pawn, pawn, pawn, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, pawn, pawn, pawn, pawn, pawn, pawn, pawn, pawn, rook, knight, bishop, queen, king, bishop, knight, rook}; const short Stcolor[64] = {white, white, white, white, white, white, white, white, white, white, white, white, white, white, white, white, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, black, black, black, black, black, black, black, black, black, black, black, black, black, black, black, black}; short board[64], color[64]; static unsigned char nextpos[8][64][64]; static unsigned char nextdir[8][64][64]; /* ptype is used to separate white and black pawns, like this; ptyp = ptype[side][piece] piece can be used directly in nextpos/nextdir when generating moves for pieces that are not black pawns. */ static const short ptype[2][8] = { no_piece, pawn, knight, bishop, rook, queen, king, no_piece, no_piece, bpawn, knight, bishop, rook, queen, king, no_piece}; static const short direc[8][8] = { 0, 0, 0, 0, 0, 0, 0, 0, 10, 9, 11, 0, 0, 0, 0, 0, 8, -8, 12, -12, 19, -19, 21, -21, 9, 11, -9, -11, 0, 0, 0, 0, 1, 10, -1, -10, 0, 0, 0, 0, 1, 10, -1, -10, 9, 11, -9, -11, 1, 10, -1, -10, 9, 11, -9, -11, -10, -9, -11, 0, 0, 0, 0, 0}; static const short max_steps[8] = {0, 2, 1, 7, 7, 7, 1, 2}; static const short nunmap[120] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, -1, -1, 8, 9, 10, 11, 12, 13, 14, 15, -1, -1, 16, 17, 18, 19, 20, 21, 22, 23, -1, -1, 24, 25, 26, 27, 28, 29, 30, 31, -1, -1, 32, 33, 34, 35, 36, 37, 38, 39, -1, -1, 40, 41, 42, 43, 44, 45, 46, 47, -1, -1, 48, 49, 50, 51, 52, 53, 54, 55, -1, -1, 56, 57, 58, 59, 60, 61, 62, 63, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}; void Initialize_moves (void) /* This procedure pre-calculates all moves for every piece from every square. This data is stored in nextpos/nextdir and used later in the move generation routines. */ { short ptyp, po, p0, d, di, s, delta; unsigned char *ppos, *pdir; short dest[8][8]; short steps[8]; short sorted[8]; for (ptyp = 0; ptyp < 8; ptyp++) for (po = 0; po < 64; po++) for (p0 = 0; p0 < 64; p0++) { nextpos[ptyp][po][p0] = (unsigned char) po; nextdir[ptyp][po][p0] = (unsigned char) po; } for (ptyp = 1; ptyp < 8; ptyp++) for (po = 21; po < 99; po++) if (nunmap[po] >= 0) { ppos = nextpos[ptyp][nunmap[po]]; pdir = nextdir[ptyp][nunmap[po]]; /* dest is a function of direction and steps */ for (d = 0; d < 8; d++) { dest[d][0] = nunmap[po]; delta = direc[ptyp][d]; if (delta != 0) { p0 = po; for (s = 0; s < max_steps[ptyp]; s++) { p0 = p0 + delta; /* break if (off board) or (pawns only move two steps from home square) */ if (nunmap[p0] < 0 || (ptyp == pawn || ptyp == bpawn) && s > 0 && (d > 0 || Stboard[nunmap[po]] != pawn)) break; else dest[d][s] = nunmap[p0]; } } else s = 0; /* sort dest in number of steps order currently no sort is done due to compability with the move generation order in old gnu chess */ steps[d] = s; for (di = d; s > 0 && di > 0; di--) if (steps[sorted[di - 1]] == 0) /* should be: < s */ sorted[di] = sorted[di - 1]; else break; sorted[di] = d; } /* update nextpos/nextdir, pawns have two threads (capture and no capture) */ p0 = nunmap[po]; if (ptyp == pawn || ptyp == bpawn) { for (s = 0; s < steps[0]; s++) { ppos[p0] = (unsigned char) dest[0][s]; p0 = dest[0][s]; } p0 = nunmap[po]; for (d = 1; d < 3; d++) { pdir[p0] = (unsigned char) dest[d][0]; p0 = dest[d][0]; } } else { pdir[p0] = (unsigned char) dest[sorted[0]][0]; for (d = 0; d < 8; d++) for (s = 0; s < steps[sorted[d]]; s++) { ppos[p0] = (unsigned char) dest[sorted[d]][s]; p0 = dest[sorted[d]][s]; if (d < 7) pdir[p0] = (unsigned char) dest[sorted[d + 1]][0]; /* else is already initialized */ } } } } /* hmm.... shouldn`t main be moved to the interface routines */ int main (int argc, char **argv) { short int ahead = true, hash = true; char *xwin = 0; while (argc > 1 && ((argv[1][0] == '-') || (argv[1][0] == '+'))) { switch (argv[1][1]) { case 'a': ahead = (argv[1][0] == '-') ? false : true; break; case 'h': hash = (argv[1][0] == '-') ? false : true; break; #if ttblsz #ifdef HASHFILE case 't': /* create or test persistent transposition table */ { if ((hashfile = fopen (HASHFILE, RWA_ACC)) == NULL) hashfile = fopen (HASHFILE , WA_ACC); if (hashfile != NULL) { long i, j; int nr[maxdepth]; struct fileentry n; printf("Counting transposition file entries, wait!\n"); for(i = 0; i < maxdepth; i++) nr[i] = 0; fseek(hashfile, 0L, SEEK_END); i = ftell(hashfile) / sizeof(struct fileentry); fseek(hashfile, 0L, SEEK_SET); for (j = 0; j < i; j++) { fread(&n, sizeof(struct fileentry), 1, hashfile); if (n.depth) { nr[n.depth]++; nr[0]++; } } printf("The file contains %d entries out of max %d\n", nr[0], i); for(j = 1; j < maxdepth; j++) printf("%d ",nr[j]); printf("\n"); if (i < filesz) { printf("Filling transposition file, wait!\n"); for(j = 0; j < 32; j++) n.bd[j] = 0; n.f = n.t = 0; n.flags = 0; n.depth = 0; n.sh = n.sl = 0; for (j = i; j < filesz; j++) fwrite (&n, sizeof(struct fileentry), 1, hashfile); } fclose(hashfile); } return(0); break; } #endif /* HASHFILE */ #endif /* ttblsz */ case 'x': xwin = &argv[1][2]; break; default: fprintf (stderr, "Usage: gnuchess [-a] [-t] [-x xwndw]\n"); } argv++; argc--; } Level = 0; TCflag = false; OperatorTime = 0; if (argc == 2) Level = atoi (argv[1]); if (argc == 3) { TCmoves = atoi (argv[1]); TCminutes = atoi (argv[2]); TCflag = true; } Initialize (); Initialize_dist (); Initialize_moves (); NewGame (); GetOpenings (); flag.easy = ahead; flag.hash = hash; if (xwin) xwndw = atoi (xwin); hashfile = NULL; #if ttblsz #ifdef HASHFILE hashfile = fopen (HASHFILE, RWA_ACC); #endif /* HASHFILE */ #endif /* ttblsz */ while (!(flag.quit)) { if (flag.bothsides && !flag.mate) SelectMove (opponent, 1); else InputCommand (); if (!(flag.quit || flag.mate || flag.force)) SelectMove (computer, 1); } #if ttblsz #ifdef HASHFILE if (hashfile) fclose(hashfile); #endif /* HASHFILE */ #endif /* ttblsz */ ExitChess (); return (0); } void NewGame (void) /* Reset the board and other variables to start a new game. */ { short l, c, p; stage = stage2 = -1; /* the game is not yet started */ flag.mate = flag.post = flag.quit = flag.reverse = flag.bothsides = false; flag.force = false; flag.hash = flag.easy = flag.beep = flag.rcptr = true; NodeCnt = et0 = epsquare = 0; dither = 0; Awindow = 90; Bwindow = 90; xwndw = 90; MaxSearchDepth = 29; contempt = 0; GameCnt = 0; Game50 = 1; hint = 0x0C14; ZeroRPT (); Developed[white] = Developed[black] = false; castld[white] = castld[black] = false; PawnThreat[0] = CptrFlag[0] = false; Pscore[0] = 12000; Tscore[0] = 12000; opponent = white; computer = black; for (l = 0; l < 2000; l++) Tree[l].f = Tree[l].t = 0; #if ttblsz rehash = 6; ZeroTTable (); srand ((unsigned int) 1); for (c = white; c <= black; c++) for (p = pawn; p <= king; p++) for (l = 0; l < 64; l++) { hashcode[c][p][l].key = (((unsigned long) urand ())); hashcode[c][p][l].key += (((unsigned long) urand ()) << 16); hashcode[c][p][l].bd = (((unsigned long) urand ())); hashcode[c][p][l].bd += (((unsigned long) urand ()) << 16); if (sizeof(long) > 4) { hashcode[c][p][l].key += (((unsigned long) urand ()) << 32); hashcode[c][p][l].key += (((unsigned long) urand ()) << 48); hashcode[c][p][l].bd += (((unsigned long) urand ()) << 32); hashcode[c][p][l].bd += (((unsigned long) urand ()) << 48); } } #endif /* ttblsz */ for (l = 0; l < 64; l++) { board[l] = Stboard[l]; color[l] = Stcolor[l]; Mvboard[l] = 0; } ClrScreen (); if (TCflag) SetTimeControl (); else if (Level == 0) SelectLevel (); InitializeStats (); time0 = time ((long *) 0); ElapsedTime (1); UpdateDisplay (0, 0, 1, 0); } /* ............ MOVE GENERATION & SEARCH ROUTINES .............. */ static inline void pick (short int p1, short int p2) /* Find the best move in the tree between indexes p1 and p2. Swap the best move into the p1 element. */ { register short p, s; short p0, s0; struct leaf temp; s0 = Tree[p1].score; p0 = p1; for (p = p1 + 1; p <= p2; p++) if ((s = Tree[p].score) > s0) { s0 = s; p0 = p; } if (p0 != p1) { temp = Tree[p1]; Tree[p1] = Tree[p0]; Tree[p0] = temp; } } void SelectMove (short int side, short int iop) /* Select a move by calling function search() at progressively deeper ply until time is up or a mate or draw is reached. An alpha-beta window of -90 to +90 points is set around the score returned from the previous iteration. If Sdepth != 0 then the program has correctly predicted the opponents move and the search will start at a depth of Sdepth+1 rather than a depth of 1. */ { static short i, tempb, tempc, tempsf, tempst, xside, rpt; static short alpha, beta, score; flag.timeout = false; xside = otherside[side]; if (iop != 2) player = side; if (TCflag) { if ((TimeControl.moves[side] + 3) != 0) ResponseTime = (TimeControl.clock[side]) / (TimeControl.moves[side] + 3) - OperatorTime; else ResponseTime = 0; ResponseTime += (ResponseTime * TimeControl.moves[side]) / (2 * TCmoves + 1); } else ResponseTime = Level; if (iop == 2) ResponseTime = 99999; if (Sdepth > 0 && root->score > Zscore - zwndw) ResponseTime -= ft; else if (ResponseTime < 1) ResponseTime = 1; ExtraTime = 0; ExaminePosition (); ScorePosition (side, &score); /* Pscore[0] = -score; */ ShowSidetomove (); if (Sdepth == 0) { #if ttblsz /* ZeroTTable (); */ #endif /* ttblsz */ SearchStartStuff (side); #ifdef NOMEMSET for (i = 0; i < 8192; i++) history[i] = 0; #else memset ((char *) history, 0, sizeof (history)); #endif /* NOMEMSET */ FROMsquare = TOsquare = -1; PV = 0; if (iop != 2) hint = 0; for (i = 0; i < maxdepth; i++) PrVar[i] = killr0[i] = killr1[i] = killr2[i] = killr3[i] = 0; alpha = score - 90; beta = score + 90; rpt = 0; TrPnt[1] = 0; root = &Tree[0]; MoveList (side, 1); for (i = TrPnt[1]; i < TrPnt[2]; i++) pick (i, TrPnt[2] - 1); if (Book != NULL) OpeningBook (&hint); if (Book != NULL) flag.timeout = true; NodeCnt = ETnodes = EvalNodes = HashCnt = FHashCnt = HashCol = 0; Zscore = 0; zwndw = 20; } while (!flag.timeout && Sdepth < MaxSearchDepth) { Sdepth++; ShowDepth (' '); score = search (side, 1, Sdepth, alpha, beta, PrVar, &rpt); for (i = 1; i <= Sdepth; i++) killr0[i] = PrVar[i]; if (score < alpha) { ShowDepth ('-'); ExtraTime = 10 * ResponseTime; /* ZeroTTable (); */ score = search (side, 1, Sdepth, -9000, score, PrVar, &rpt); } if (score > beta && !(root->flags & exact)) { ShowDepth ('+'); ExtraTime = 0; /* ZeroTTable (); */ score = search (side, 1, Sdepth, score, 9000, PrVar, &rpt); } score = root->score; if (!flag.timeout) for (i = TrPnt[1] + 1; i < TrPnt[2]; i++) pick (i, TrPnt[2] - 1); ShowResults (score, PrVar, '.'); for (i = 1; i <= Sdepth; i++) killr0[i] = PrVar[i]; if (score > Zscore - zwndw && score > Tree[1].score + 250) ExtraTime = 0; else if (score > Zscore - 3 * zwndw) ExtraTime = ResponseTime; else ExtraTime = 3 * ResponseTime; if (root->flags & exact) flag.timeout = true; if (Tree[1].score < -9000) flag.timeout = true; if (4 * et > 2 * ResponseTime + ExtraTime) flag.timeout = true; if (!flag.timeout) { Tscore[0] = score; if (Zscore == 0) Zscore = score; else Zscore = (Zscore + score) / 2; } zwndw = 20 + abs (Zscore / 12); beta = score + Bwindow; if (Zscore < score) alpha = Zscore - Awindow - zwndw; else alpha = score - Awindow - zwndw; } score = root->score; if (rpt >= 2 || score < -12000) root->flags |= draw; if (iop == 2) return; if (Book == NULL) hint = PrVar[2]; ElapsedTime (1); if (score > -9999 && rpt <= 2) { MakeMove (side, root, &tempb, &tempc, &tempsf, &tempst, &INCscore); algbr (root->f, root->t, (short) root->flags); } else algbr (0, 0, 0); OutputMove (); if (score == -9999 || score == 9998) flag.mate = true; if (flag.mate) hint = 0; if ((board[root->t] == pawn) || (root->flags & capture) || (root->flags & cstlmask)) { Game50 = GameCnt; ZeroRPT (); } GameList[GameCnt].score = score; GameList[GameCnt].nodes = NodeCnt; GameList[GameCnt].time = (short) et; GameList[GameCnt].depth = Sdepth; if (TCflag) { TimeControl.clock[side] -= (et + OperatorTime); if (--TimeControl.moves[side] == 0) SetTimeControl (); } if ((root->flags & draw) && flag.bothsides) flag.mate = true; if (GameCnt > 470) flag.mate = true; /* out of move store, you loose */ player = xside; Sdepth = 0; fflush (stdin); } int parse (FILE *fd, unsigned short int *mv, short int side) { int c, i, r1, r2, c1, c2; char s[100]; while ((c = getc (fd)) == ' ') ; i = 0; s[0] = (char) c; while (c != ' ' && c != '\n' && c != EOF) s[++i] = (char) (c = getc (fd)); s[++i] = '\0'; if (c == EOF) return (-1); if (s[0] == '!' || s[0] == ';' || i < 3) { while (c != '\n' && c != EOF) c = getc (fd); return (0); } if (s[4] == 'o') if (side == black) *mv = 0x3C3A; else *mv = 0x0402; else if (s[0] == 'o') if (side == black) *mv = 0x3C3E; else *mv = 0x0406; else { c1 = s[0] - 'a'; r1 = s[1] - '1'; c2 = s[2] - 'a'; r2 = s[3] - '1'; *mv = (locn (r1, c1) << 8) | locn (r2, c2); } return (1); } void GetOpenings (void) /* Read in the Opening Book file and parse the algebraic notation for a move into an unsigned integer format indicating the from and to square. Create a linked list of opening lines of play, with entry->next pointing to the next line and entry->move pointing to a chunk of memory containing the moves. More Opening lines of up to 256 half moves may be added to gnuchess.book. */ #ifndef BOOK #define BOOK "/usr/games/lib/gnuchess.book" #endif /* BOOK */ { FILE *fd; int c, i, j, side; /* char buffr[2048]; */ struct BookEntry *entry; unsigned short mv, *mp, tmp[100]; if ((fd = fopen (BOOK, "r")) == NULL) fd = fopen ("gnuchess.book", "r"); if (fd != NULL) { /* setvbuf(fd,buffr,_IOFBF,2048); */ Book = NULL; i = 0; side = white; while ((c = parse (fd, &mv, side)) >= 0) if (c == 1) { tmp[++i] = mv; side = otherside[side]; } else if (c == 0 && i > 0) { entry = (struct BookEntry *) malloc (sizeof (struct BookEntry)); mp = (unsigned short *) malloc ((i + 1) * sizeof (unsigned short)); if (!entry || !mp) { Book = NULL; ShowMessage ("warning: can\'t load book, out of memory."); return; } entry->mv = mp; entry->next = Book; Book = entry; for (j = 1; j <= i; j++) *(mp++) = tmp[j]; *mp = 0; i = 0; side = white; } fclose (fd); } else ShowMessage ("warning: can\'t find book."); } void OpeningBook (unsigned short *hint) /* Go thru each of the opening lines of play and check for a match with the current game listing. If a match occurs, generate a random number. If this number is the largest generated so far then the next move in this line becomes the current "candidate". After all lines are checked, the candidate move is put at the top of the Tree[] array and will be played by the program. Note that the program does not handle book transpositions. */ { short j, pnt; unsigned short m, *mp; unsigned r, r0; struct BookEntry *p; srand ((unsigned int) time ((long *) 0)); r0 = m = 0; p = Book; while (p != NULL) { mp = p->mv; for (j = 1; j <= GameCnt; j++) if (GameList[j].gmove != *(mp++)) break; if (j > GameCnt) if ((r = urand ()) > r0) { r0 = r; m = *mp; *hint = *(++mp); } p = p->next; } for (pnt = TrPnt[1]; pnt < TrPnt[2]; pnt++) if (((Tree[pnt].f << 8) | Tree[pnt].t) == m) Tree[pnt].score = 0; pick (TrPnt[1], TrPnt[2] - 1); if (Tree[TrPnt[1]].score < 0) Book = NULL; } inline void repetition (short int *cnt) /* Check for draw by threefold repetition. */ { register short i, c, f, t; short b[64]; unsigned short m; *cnt = c = 0; if (GameCnt > Game50 + 3) { #ifdef NOMEMSET for (i = 0; i < 64; b[i++] = 0) ; #else memset ((char *) b, 0, sizeof (b)); #endif /* NOMEMSET */ for (i = GameCnt; i > Game50; i--) { m = GameList[i].gmove; f = m >> 8; t = m & 0xFF; if (++b[f] == 0) c--; else c++; if (--b[t] == 0) c--; else c++; if (c == 0) (*cnt)++; } } } int search (short int side, short int ply, short int depth, short int alpha, short int beta, unsigned short int *bstline, short int *rpt) /* Perform an alpha-beta search to determine the score for the current board position. If depth <= 0 only capturing moves, pawn promotions and responses to check are generated and searched, otherwise all moves are processed. The search depth is modified for check evasions, certain re-captures and threats. Extensions may continue for up to 11 ply beyond the nominal search depth. */ #define UpdateSearchStatus \ {\ if (flag.post) ShowCurrentMove(pnt,node->f,node->t);\ if (pnt > TrPnt[1])\ {\ d = best-Zscore; e = best-node->score;\ if (best < alpha) ExtraTime = 10*ResponseTime;\ else if (d > -zwndw && e > 4*zwndw) ExtraTime = -ResponseTime/3;\ else if (d > -zwndw) ExtraTime = 0;\ else if (d > -3*zwndw) ExtraTime = ResponseTime;\ else if (d > -9*zwndw) ExtraTime = 3*ResponseTime;\ else ExtraTime = 5*ResponseTime;\ }\ } #define prune (cf && score+node->score < alpha) #define ReCapture (flag.rcptr && score > alpha && score < beta &&\ ply > 2 && CptrFlag[ply-1] && CptrFlag[ply-2]) /* && depth == Sdepth-ply+1 */ #define Parry (hung[side] > 1 && ply == Sdepth+1) #define MateThreat (ply < Sdepth+4 && ply > 4 &&\ ChkFlag[ply-2] && ChkFlag[ply-4] &&\ ChkFlag[ply-2] != ChkFlag[ply-4]) { register short j, pnt; short best, tempb, tempc, tempsf, tempst; short xside, pbst, d, e, cf, score, rcnt, slk, InChk; unsigned short mv, nxtline[maxdepth]; struct leaf *node, tmp; NodeCnt++; xside = otherside[side]; if ((ply <= Sdepth + 3) && rpthash[side][hashkey & 0xFF] > 0) repetition (rpt); else *rpt = 0; /* Detect repetitions a bit earlier. SMC. 12/89 */ if (*rpt == 1 && ply > 1) return (0); /* if (*rpt >= 2) return(0); */ score = evaluate (side, ply, alpha, beta, INCscore, &slk, &InChk); if (score > 9000) { bstline[ply] = 0; return (score); } if (depth > 0) { /* Allow opponent a chance to check again */ if (InChk) depth = (depth < 2) ? 2 : depth; else if (PawnThreat[ply - 1] || ReCapture) ++depth; } else { if (score >= alpha && (InChk || PawnThreat[ply - 1] || Parry)) depth = 1; else if (score <= beta && MateThreat) depth = 1; } #if ttblsz if (depth > 0 && flag.hash && ply > 1) { if (ProbeTTable (side, depth, &alpha, &beta, &score) == false) #ifdef HASHFILE if (hashfile && (depth > 5) && (GameCnt < 12)) ProbeFTable (side, depth, &alpha, &beta, &score); #else /* do nothing */; #endif /* HASHFILE */ bstline[ply] = PV; bstline[ply + 1] = 0; if (beta == -20000) return (score); if (alpha > beta) return (alpha); } #endif /* ttblsz */ if (Sdepth == 1) d = 7; else d = 11; if (ply > Sdepth + d || (depth < 1 && score > beta)) /* score >= beta ?? */ return (score); if (ply > 1) if (depth > 0) MoveList (side, ply); else CaptureList (side, ply); if (TrPnt[ply] == TrPnt[ply + 1]) return (score); cf = (depth < 1 && ply > Sdepth + 1 && !ChkFlag[ply - 2] && !slk); if (depth > 0) best = -12000; else best = score; if (best > alpha) alpha = best; for (pnt = pbst = TrPnt[ply]; pnt < TrPnt[ply + 1] && best <= beta; /* best < beta ?? */ pnt++) { if (ply > 1) pick (pnt, TrPnt[ply + 1] - 1); node = &Tree[pnt]; mv = (node->f << 8) | node->t; nxtline[ply + 1] = 0; if (prune) break; if (ply == 1) UpdateSearchStatus; if (!(node->flags & exact)) { MakeMove (side, node, &tempb, &tempc, &tempsf, &tempst, &INCscore); CptrFlag[ply] = (node->flags & capture); PawnThreat[ply] = (node->flags & pwnthrt); Tscore[ply] = node->score; PV = node->reply; node->score = -search (xside, ply + 1, (depth > 0) ? depth - 1 : 0, -beta, -alpha, nxtline, &rcnt); if (abs (node->score) > 9000) node->flags |= exact; else if (rcnt == 1) node->score /= 2; if (rcnt >= 2 || GameCnt - Game50 > 99 || (node->score == 9999 - ply && !ChkFlag[ply])) { node->flags |= draw; node->flags |= exact; if (side == computer) node->score = contempt; else node->score = -contempt; } node->reply = nxtline[ply + 1]; UnmakeMove (side, node, &tempb, &tempc, &tempsf, &tempst); } if (node->score > best && !flag.timeout) { if (depth > 0) if (node->score > alpha && !(node->flags & exact)) node->score += depth; best = node->score; pbst = pnt; if (best > alpha) alpha = best; for (j = ply + 1; nxtline[j] > 0; j++) bstline[j] = nxtline[j]; bstline[j] = 0; bstline[ply] = mv; if (ply == 1) { if (best > root->score) { tmp = Tree[pnt]; for (j = pnt - 1; j >= 0; j--) Tree[j + 1] = Tree[j]; Tree[0] = tmp; pbst = 0; } if (Sdepth > 2) if (best > beta) ShowResults (best, bstline, '+'); else if (best < alpha) ShowResults (best, bstline, '-'); else ShowResults (best, bstline, '&'); } } if (NodeCnt > ETnodes) ElapsedTime (0); if (flag.timeout) return (-Tscore[ply - 1]); } node = &Tree[pbst]; mv = (node->f << 8) | node->t; #if ttblsz if (flag.hash && ply <= Sdepth && *rpt == 0 && best == alpha) { PutInTTable (side, best, depth, alpha, beta, mv); #ifdef HASHFILE if (hashfile && (depth > 5) && (GameCnt < 12)) PutInFTable (side, best, depth, alpha, beta, node->f, node->t); #endif /* HASHFILE */ } #endif /* ttblsz */ if (depth > 0) { j = (node->f << 6) | node->t; if (side == black) j |= 0x1000; if (history[j] < 150) history[j] += (unsigned char) 2 * depth; if (node->t != (GameList[GameCnt].gmove & 0xFF)) if (best <= beta) killr3[ply] = mv; else if (mv != killr1[ply]) { killr2[ply] = killr1[ply]; killr1[ply] = mv; } if (best > 9000) killr0[ply] = mv; else killr0[ply] = 0; } return (best); } #if ttblsz /* hashbd contains a 32 bit "signature" of the board position. hashkey contains a 16 bit code used to address the hash table. When a move is made, XOR'ing the hashcode of moved piece on the from and to squares with the hashbd and hashkey values keeps things current. */ #define UpdateHashbd(side, piece, f, t) \ {\ if ((f) >= 0)\ {\ hashbd ^= hashcode[side][piece][f].bd;\ hashkey ^= hashcode[side][piece][f].key;\ }\ if ((t) >= 0)\ {\ hashbd ^= hashcode[side][piece][t].bd;\ hashkey ^= hashcode[side][piece][t].key;\ }\ } #define CB(i) (unsigned char) ((color[2 * (i)] ? 0x80 : 0)\ | (board[2 * (i)] << 4)\ | (color[2 * (i) + 1] ? 0x8 : 0)\ | (board[2 * (i) + 1])) int ProbeTTable (short int side, short int depth, short int *alpha, short int *beta, short int *score) /* Look for the current board position in the transposition table. */ { register struct hashentry *ptbl; register unsigned short i; ptbl = &ttable[side][hashkey & (ttblsz - 1)]; /* rehash max rehash times */ for (i = 1; ptbl->hashbd != hashbd && i <= rehash; i++) ptbl = &ttable[side][(hashkey + i) & (ttblsz - 1)]; if ((short) ptbl->depth >= depth && ptbl->hashbd == hashbd) { HashCnt++; #ifdef HASHTEST for (i = 0; i < 32; i++) { if (ptbl->bd[i] != CB(i)) { HashCol++; ShowMessage("ttable collision detected"); break; } } #endif /* HASHTEST */ PV = ptbl->mv; if (ptbl->flags & truescore) { *score = ptbl->score; *beta = -20000; } #if 0 /* commented out, why? */ else if (ptbl->flags & upperbound) { if (ptbl->score < *beta) *beta = ptbl->score+1; } #endif else if (ptbl->flags & lowerbound) { if (ptbl->score > *alpha) *alpha = ptbl->score - 1; } return(true); } return(false); } void PutInTTable (short int side, short int score, short int depth, short int alpha, short int beta, unsigned short int mv) /* Store the current board position in the transposition table. */ { register struct hashentry *ptbl; register unsigned short i; ptbl = &ttable[side][hashkey & (ttblsz - 1)]; /* rehash max rehash times */ for (i = 1; depth < ptbl->depth && ptbl->hashbd != hashbd && i <= rehash; i++) ptbl = &ttable[side][(hashkey + i) & (ttblsz - 1)]; if (depth >= ptbl->depth || ptbl->hashbd != hashbd) { ptbl->hashbd = hashbd; ptbl->depth = (unsigned char) depth; ptbl->score = score; ptbl->mv = mv; ptbl->flags = 0; if (score < alpha) ptbl->flags |= upperbound; else if (score > beta) ptbl->flags |= lowerbound; else ptbl->flags |= truescore; #ifdef HASHTEST for (i = 0; i < 32; i++) { ptbl->bd[i] = CB(i); } #endif /* HASHTEST */ } } void ZeroTTable (void) { register int side, i; if (flag.hash) for (side = white; side <= black; side++) for (i = 0; i < ttblsz; i++) ttable[side][i].depth = 0; } #ifdef HASHFILE int ProbeFTable(short int side, short int depth, short int *alpha, short int *beta, short int *score) /* Look for the current board position in the persistent transposition table. */ { register unsigned short i, j; register unsigned long hashix; short s; struct fileentry new, t; if (side == white) hashix = hashkey & 0xFFFFFFFE & (filesz - 1); else hashix = hashkey | 1 & (filesz - 1); for (i = 0; i < 32; i++) new.bd[i] = CB(i); new.flags = 0; if ((Mvboard[kingP[side]] == 0) && (Mvboard[qrook[side]] == 0)) new.flags |= queencastle; if ((Mvboard[kingP[side]] == 0) && (Mvboard[krook[side]] == 0)) new.flags |= kingcastle; for (i = 0; i < frehash; i++) { fseek(hashfile, sizeof(struct fileentry) * ((hashix + 2 * i) & (filesz - 1)), SEEK_SET); fread(&t, sizeof(struct fileentry), 1, hashfile); for (j = 0; j < 32; j++) if (t.bd[j] != new.bd[j]) break; if (((short) t.depth >= depth) && (j >= 32) && (new.flags == (t.flags & (kingcastle | queencastle)))) { FHashCnt++; PV = (t.f << 8) | t.t; s = (t.sh << 8) | t.sl; if (t.flags & truescore) { *score = s; *beta = -20000; } else if (t.flags & lowerbound) { if (s > *alpha) *alpha = s - 1; } return(true); } } return(false); } void PutInFTable (short int side, short int score, short int depth, short int alpha, short int beta, short unsigned int f, short unsigned int t) /* Store the current board position in the persistent transposition table. */ { register unsigned short i; register unsigned long hashix; struct fileentry new, tmp; if (side == white) hashix = hashkey & 0xFFFFFFFE & (filesz - 1); else hashix = hashkey | 1 & (filesz - 1); for (i = 0; i < 32; i++) new.bd[i] = CB(i); new.f = (unsigned char) f; new.t = (unsigned char) t; new.flags = 0; if (score < alpha) new.flags |= upperbound; else if (score > beta) new.flags |= lowerbound; else new.flags |= truescore; if ((Mvboard[kingP[side]] == 0) && (Mvboard[qrook[side]] == 0)) new.flags |= queencastle; if ((Mvboard[kingP[side]] == 0) && (Mvboard[krook[side]] == 0)) new.flags |= kingcastle; new.depth = (unsigned char) depth; new.sh = (unsigned char) (score >> 8); new.sl = (unsigned char) (score & 0xFF); for (i = 0; i < frehash; i++) { fseek(hashfile, sizeof(struct fileentry) * ((hashix + 2 * i) & (filesz - 1)), SEEK_SET); fread(&tmp, sizeof(struct fileentry), 1, hashfile); if ((short) tmp.depth <= depth) { fseek(hashfile, sizeof(struct fileentry) * ((hashix + 2 * i) & (filesz - 1)), SEEK_SET); fwrite (&new, sizeof(struct fileentry), 1, hashfile); break; } } } #endif /* HASHFILE */ #endif /* ttblsz */ void ZeroRPT (void) { register int side, i; for (side = white; side <= black; side++) for (i = 0; i < 256; i++) rpthash[side][i] = 0; } #define Link(from,to,flag,s) \ {\ node->f = from; node->t = to;\ node->reply = 0;\ node->flags = flag;\ node->score = s;\ ++node;\ ++TrPnt[ply+1];\ } static inline void LinkMove (short int ply, short int f, short int t, short int flag, short int xside) /* Add a move to the tree. Assign a bonus to order the moves as follows: 1. Principle variation 2. Capture of last moved piece 3. Other captures (major pieces first) 4. Killer moves 5. "history" killers */ { register short s, z; register unsigned short mv; register struct leaf *node; node = &Tree[TrPnt[ply + 1]]; mv = (f << 8) | t; s = 0; if (mv == Swag0) s = 2000; else if (mv == Swag1) s = 60; else if (mv == Swag2) s = 50; else if (mv == Swag3) s = 40; else if (mv == Swag4) s = 30; z = (f << 6) | t; if (xside == white) z |= 0x1000; s += history[z]; if (color[t] != neutral) { if (t == TOsquare) s += 500; s += value[board[t]] - board[f]; } if (board[f] == pawn) if (row (t) == 0 || row (t) == 7) { flag |= promote; s += 800; Link (f, t, flag | queen, s - 20000); s -= 200; Link (f, t, flag | knight, s - 20000); s -= 50; Link (f, t, flag | rook, s - 20000); flag |= bishop; s -= 50; } else if (row (t) == 1 || row (t) == 6) { flag |= pwnthrt; s += 600; } Link (f, t, flag, s - 20000); } static inline void GenMoves (short int ply, short int sq, short int side, short int xside) /* Generate moves for a piece. The moves are taken from the precalulated array nextpos/nextdir. If the board is free, next move is choosen from nextpos else from nextdir. */ { register short u, piece; register unsigned char *ppos, *pdir; piece = board[sq]; ppos = nextpos[ptype[side][piece]][sq]; pdir = nextdir[ptype[side][piece]][sq]; if (piece == pawn) { u = ppos[sq]; /* follow no captures thread */ if (color[u] == neutral) { LinkMove (ply, sq, u, 0, xside); u = ppos[u]; if (color[u] == neutral) LinkMove (ply, sq, u, 0, xside); } u = pdir[sq]; /* follow captures thread */ if (color[u] == xside) LinkMove (ply, sq, u, capture, xside); else if (u == epsquare) LinkMove (ply, sq, u, capture | epmask, xside); u = pdir[u]; if (color[u] == xside) LinkMove (ply, sq, u, capture, xside); else if (u == epsquare) LinkMove (ply, sq, u, capture | epmask, xside); } else { u = ppos[sq]; do { if (color[u] == neutral) { LinkMove (ply, sq, u, 0, xside); u = ppos[u]; } else { if (color[u] == xside) LinkMove (ply, sq, u, capture, xside); u = pdir[u]; } } while (u != sq); } } void MoveList (short int side, short int ply) /* Fill the array Tree[] with all available moves for side to play. Array TrPnt[ply] contains the index into Tree[] of the first move at a ply. */ { register short i, xside, f; xside = otherside[side]; TrPnt[ply + 1] = TrPnt[ply]; if (PV == 0) Swag0 = killr0[ply]; else Swag0 = PV; Swag1 = killr1[ply]; Swag2 = killr2[ply]; Swag3 = killr3[ply]; if (ply > 2) Swag4 = killr1[ply - 2]; else Swag4 = 0; for (i = PieceCnt[side]; i >= 0; i--) GenMoves (ply, PieceList[side][i], side, xside); if (!castld[side]) { f = PieceList[side][0]; if (castle (side, f, f + 2, 0)) { LinkMove (ply, f, f + 2, cstlmask, xside); } if (castle (side, f, f - 2, 0)) { LinkMove (ply, f, f - 2, cstlmask, xside); } } } void CaptureList (short int side, short int ply) /* Fill the array Tree[] with all available cature and promote moves for side to play. Array TrPnt[ply] contains the index into Tree[] of the first move at a ply. */ { register short u, sq, xside; register struct leaf *node; register unsigned char *ppos, *pdir; short i, piece, *PL, r7; xside = otherside[side]; TrPnt[ply + 1] = TrPnt[ply]; node = &Tree[TrPnt[ply]]; r7 = rank7[side]; PL = PieceList[side]; for (i = 0; i <= PieceCnt[side]; i++) { sq = PL[i]; piece = board[sq]; if (sweep[piece]) { ppos = nextpos[piece][sq]; pdir = nextdir[piece][sq]; u = ppos[sq]; do { if (color[u] == neutral) u = ppos[u]; else { if (color[u] == xside) Link (sq, u, capture, value[board[u]] + svalue[board[u]] - piece); u = pdir[u]; } } while (u != sq); } else { pdir = nextdir[ptype[side][piece]][sq]; if (piece == pawn && row (sq) == r7) { u = pdir[sq]; if (color[u] == xside) Link (sq, u, capture | promote | queen, valueQ); u = pdir[u]; if (color[u] == xside) Link (sq, u, capture | promote | queen, valueQ); ppos = nextpos[ptype[side][piece]][sq]; u = ppos[sq]; /* also generate non capture promote */ if (color[u] == neutral) Link (sq, u, promote | queen, valueQ); } else { u = pdir[sq]; do { if (color[u] == xside) Link (sq, u, capture, value[board[u]] + svalue[board[u]] - piece); u = pdir[u]; } while (u != sq); } } } } int castle (short int side, short int kf, short int kt, short int iop) /* Make or Unmake a castling move. */ { register short rf, rt, t0, xside; xside = otherside[side]; if (kt > kf) { rf = kf + 3; rt = kt - 1; } else { rf = kf - 4; rt = kt + 1; } if (iop == 0) { if (kf != kingP[side] || board[kf] != king || board[rf] != rook || Mvboard[kf] != 0 || Mvboard[rf] != 0 || color[kt] != neutral || color[rt] != neutral || color[kt - 1] != neutral || SqAtakd (kf, xside) || SqAtakd (kt, xside) || SqAtakd (rt, xside)) return (false); } else { if (iop == 1) { castld[side] = true; Mvboard[kf]++; Mvboard[rf]++; } else { castld[side] = false; Mvboard[kf]--; Mvboard[rf]--; t0 = kt; kt = kf; kf = t0; t0 = rt; rt = rf; rf = t0; } board[kt] = king; color[kt] = side; Pindex[kt] = 0; board[kf] = no_piece; color[kf] = neutral; board[rt] = rook; color[rt] = side; Pindex[rt] = Pindex[rf]; board[rf] = no_piece; color[rf] = neutral; PieceList[side][Pindex[kt]] = kt; PieceList[side][Pindex[rt]] = rt; #if ttblsz UpdateHashbd (side, king, kf, kt); UpdateHashbd (side, rook, rf, rt); #endif /* ttblsz */ } return (true); } static inline void EnPassant (short int xside, short int f, short int t, short int iop) /* Make or unmake an en passant move. */ { register short l; if (t > f) l = t - 8; else l = t + 8; if (iop == 1) { board[l] = no_piece; color[l] = neutral; } else { board[l] = pawn; color[l] = xside; } InitializeStats (); } static inline void UpdatePieceList (short int side, short int sq, short int iop) /* Update the PieceList and Pindex arrays when a piece is captured or when a capture is unmade. */ { register short i; if (iop == 1) { PieceCnt[side]--; for (i = Pindex[sq]; i <= PieceCnt[side]; i++) { PieceList[side][i] = PieceList[side][i + 1]; Pindex[PieceList[side][i]] = i; } } else { PieceCnt[side]++; PieceList[side][PieceCnt[side]] = sq; Pindex[sq] = PieceCnt[side]; } } void MakeMove (short int side, struct leaf * node, short int *tempb, short int *tempc, short int *tempsf, short int *tempst, short int *INCscore) /* Update Arrays board[], color[], and Pindex[] to reflect the new board position obtained after making the move pointed to by node. Also update miscellaneous stuff that changes when a move is made. */ { register short f, t, xside, ct, cf; xside = otherside[side]; GameCnt++; f = node->f; t = node->t; epsquare = -1; FROMsquare = f; TOsquare = t; *INCscore = 0; GameList[GameCnt].gmove = (f << 8) | t; if (node->flags & cstlmask) { GameList[GameCnt].piece = no_piece; GameList[GameCnt].color = side; (void) castle (side, f, t, 1); } else { if (!(node->flags & capture) && (board[f] != pawn)) rpthash[side][hashkey & 0xFF]++; *tempc = color[t]; *tempb = board[t]; *tempsf = svalue[f]; *tempst = svalue[t]; GameList[GameCnt].piece = *tempb; GameList[GameCnt].color = *tempc; if (*tempc != neutral) { UpdatePieceList (*tempc, t, 1); if (*tempb == pawn) --PawnCnt[*tempc][column (t)]; if (board[f] == pawn) { --PawnCnt[side][column (f)]; ++PawnCnt[side][column (t)]; cf = column (f); ct = column (t); if (PawnCnt[side][ct] > 1 + PawnCnt[side][cf]) *INCscore -= 15; else if (PawnCnt[side][ct] < 1 + PawnCnt[side][cf]) *INCscore += 15; else if (ct == 0 || ct == 7 || PawnCnt[side][ct + ct - cf] == 0) *INCscore -= 15; } mtl[xside] -= value[*tempb]; if (*tempb == pawn) pmtl[xside] -= valueP; #if ttblsz UpdateHashbd (xside, *tempb, -1, t); #endif /* ttblsz */ *INCscore += *tempst; Mvboard[t]++; } color[t] = color[f]; board[t] = board[f]; svalue[t] = svalue[f]; Pindex[t] = Pindex[f]; PieceList[side][Pindex[t]] = t; color[f] = neutral; board[f] = no_piece; if (board[t] == pawn) if (t - f == 16) epsquare = f + 8; else if (f - t == 16) epsquare = f - 8; if (node->flags & promote) { board[t] = node->flags & pmask; if (board[t] == queen) HasQueen[side]++; else if (board[t] == rook) HasRook[side]++; else if (board[t] == bishop) HasBishop[side]++; else if (board[t] == knight) HasKnight[side]++; --PawnCnt[side][column (t)]; mtl[side] += value[board[t]] - valueP; pmtl[side] -= valueP; #if ttblsz UpdateHashbd (side, pawn, f, -1); UpdateHashbd (side, board[t], f, -1); #endif /* ttblsz */ *INCscore -= *tempsf; } if (node->flags & epmask) EnPassant (xside, f, t, 1); else #if ttblsz UpdateHashbd (side, board[t], f, t); #else /* NOOP */; #endif /* ttblsz */ Mvboard[f]++; } } void UnmakeMove (short int side, struct leaf * node, short int *tempb, short int *tempc, short int *tempsf, short int *tempst) /* Take back a move. */ { register short f, t, xside; xside = otherside[side]; f = node->f; t = node->t; epsquare = -1; GameCnt--; if (node->flags & cstlmask) (void) castle (side, f, t, 2); else { color[f] = color[t]; board[f] = board[t]; svalue[f] = *tempsf; Pindex[f] = Pindex[t]; PieceList[side][Pindex[f]] = f; color[t] = *tempc; board[t] = *tempb; svalue[t] = *tempst; if (node->flags & promote) { board[f] = pawn; ++PawnCnt[side][column (t)]; mtl[side] += valueP - value[node->flags & pmask]; pmtl[side] += valueP; #if ttblsz UpdateHashbd (side, (short) node->flags & pmask, -1, t); UpdateHashbd (side, pawn, -1, t); #endif /* ttblsz */ } if (*tempc != neutral) { UpdatePieceList (*tempc, t, 2); if (*tempb == pawn) ++PawnCnt[*tempc][column (t)]; if (board[f] == pawn) { --PawnCnt[side][column (t)]; ++PawnCnt[side][column (f)]; } mtl[xside] += value[*tempb]; if (*tempb == pawn) pmtl[xside] += valueP; #if ttblsz UpdateHashbd (xside, *tempb, -1, t); #endif /* ttblsz */ Mvboard[t]--; } if (node->flags & epmask) EnPassant (xside, f, t, 2); else #if ttblsz UpdateHashbd (side, board[f], f, t); #else /* NOOP */; #endif /* ttblsz */ Mvboard[f]--; if (!(node->flags & capture) && (board[f] != pawn)) rpthash[side][hashkey & 0xFF]--; } } void InitializeStats (void) /* Scan thru the board seeing what's on each square. If a piece is found, update the variables PieceCnt, PawnCnt, Pindex and PieceList. Also determine the material for each side and set the hashkey and hashbd variables to represent the current board position. Array PieceList[side][indx] contains the location of all the pieces of either side. Array Pindex[sq] contains the indx into PieceList for a given square. */ { register short i, sq; epsquare = -1; for (i = 0; i < 8; i++) PawnCnt[white][i] = PawnCnt[black][i] = 0; mtl[white] = mtl[black] = pmtl[white] = pmtl[black] = 0; PieceCnt[white] = PieceCnt[black] = 0; #if ttblsz hashbd = hashkey = 0; #endif /* ttblsz */ for (sq = 0; sq < 64; sq++) if (color[sq] != neutral) { mtl[color[sq]] += value[board[sq]]; if (board[sq] == pawn) { pmtl[color[sq]] += valueP; ++PawnCnt[color[sq]][column (sq)]; } if (board[sq] == king) Pindex[sq] = 0; else Pindex[sq] = ++PieceCnt[color[sq]]; PieceList[color[sq]][Pindex[sq]] = sq; #if ttblsz hashbd ^= hashcode[color[sq]][board[sq]][sq].bd; hashkey ^= hashcode[color[sq]][board[sq]][sq].key; #endif /* ttblsz */ } } int SqAtakd (short int sq, short int side) /* See if any piece with color 'side' ataks sq. First check pawns then Queen, Bishop, Rook and King and last Knight. */ { register short u; register unsigned char *ppos, *pdir; short xside; xside = otherside[side]; pdir = nextdir[ptype[xside][pawn]][sq]; u = pdir[sq]; /* follow captures thread */ if (u != sq) { if (board[u] == pawn && color[u] == side) return (true); u = pdir[u]; if (u != sq && board[u] == pawn && color[u] == side) return (true); } /* king capture */ if (distance (sq, PieceList[side][0]) == 1) return (true); /* try a queen bishop capture */ ppos = nextpos[bishop][sq]; pdir = nextdir[bishop][sq]; u = ppos[sq]; do { if (color[u] == neutral) u = ppos[u]; else { if (color[u] == side && (board[u] == queen || board[u] == bishop)) return (true); u = pdir[u]; } } while (u != sq); /* try a queen rook capture */ ppos = nextpos[rook][sq]; pdir = nextdir[rook][sq]; u = ppos[sq]; do { if (color[u] == neutral) u = ppos[u]; else { if (color[u] == side && (board[u] == queen || board[u] == rook)) return (true); u = pdir[u]; } } while (u != sq); /* try a knight capture */ pdir = nextdir[knight][sq]; u = pdir[sq]; do { if (color[u] == side && board[u] == knight) return (true); u = pdir[u]; } while (u != sq); return (false); } static inline void ataks (short int side, short int *a) /* Fill array atak[][] with info about ataks to a square. Bits 8-15 are set if the piece (king..pawn) ataks the square. Bits 0-7 contain a count of total ataks to the square. */ { register short u, c, sq; register unsigned char *ppos, *pdir; short i, piece, *PL; #ifdef NOMEMSET for (u = 64; u; a[--u] = 0) ; #else memset ((char *) a, 0, 64 * sizeof (a[0])); #endif /* NOMEMSET */ PL = PieceList[side]; for (i = PieceCnt[side]; i >= 0; i--) { sq = PL[i]; piece = board[sq]; c = control[piece]; if (sweep[piece]) { ppos = nextpos[piece][sq]; pdir = nextdir[piece][sq]; u = ppos[sq]; do { a[u] = ++a[u] | c; u = (color[u] == neutral) ? ppos[u] : pdir[u]; } while (u != sq); } else { pdir = nextdir[ptype[side][piece]][sq]; u = pdir[sq]; /* follow captures thread for pawns */ do { a[u] = ++a[u] | c; u = pdir[u]; } while (u != sq); } } } /* ............ POSITIONAL EVALUATION ROUTINES ............ */ int evaluate (short int side, short int ply, short int alpha, short int beta, short int INCscore, short int *slk, short int *InChk) /* Compute an estimate of the score by adding the positional score from the previous ply to the material difference. If this score falls inside a window which is 180 points wider than the alpha-beta window (or within a 50 point window during quiescence search) call ScorePosition() to determine a score, otherwise return the estimated score. If one side has only a king and the other either has no pawns or no pieces then the function ScoreLoneKing() is called. */ { register short evflag, xside; short s; xside = otherside[side]; s = -Pscore[ply - 1] + mtl[side] - mtl[xside] - INCscore; hung[white] = hung[black] = 0; *slk = ((mtl[white] == valueK && (pmtl[black] == 0 || emtl[black] == 0)) || (mtl[black] == valueK && (pmtl[white] == 0 || emtl[white] == 0))); if (*slk) evflag = false; else evflag = (ply == 1 || ply < Sdepth || ((ply == Sdepth + 1 || ply == Sdepth + 2) && (s > alpha - xwndw && s < beta + xwndw)) || (ply > Sdepth + 2 && s >= alpha - 25 && s <= beta + 25)); if (evflag) { EvalNodes++; ataks (side, atak[side]); if (Anyatak (side, PieceList[xside][0])) return (10001 - ply); ataks (xside, atak[xside]); *InChk = Anyatak (xside, PieceList[side][0]); ScorePosition (side, &s); } else { if (SqAtakd (PieceList[xside][0], side)) return (10001 - ply); *InChk = SqAtakd (PieceList[side][0], xside); if (*slk) ScoreLoneKing (side, &s); } Pscore[ply] = s - mtl[side] + mtl[xside]; if (*InChk) ChkFlag[ply - 1] = Pindex[TOsquare]; else ChkFlag[ply - 1] = 0; return (s); } static inline int ScoreKPK (short int side, short int winner, short int loser, short int king1, short int king2, short int sq) /* Score King and Pawns versus King endings. */ { register short s, r; if (PieceCnt[winner] == 1) s = 50; else s = 120; if (winner == white) { if (side == loser) r = row (sq) - 1; else r = row (sq); if (row (king2) >= r && distance (sq, king2) < 8 - r) s += 10 * row (sq); else s = 500 + 50 * row (sq); if (row (sq) < 6) sq += 16; else if (row(sq) == 6) sq += 8; } else { if (side == loser) r = row (sq) + 1; else r = row (sq); if (row (king2) <= r && distance (sq, king2) < r + 1) s += 10 * (7 - row (sq)); else s = 500 + 50 * (7 - row (sq)); if (row (sq) > 1) sq -= 16; else if (row(sq) == 1) sq -= 8; } s += 8 * (taxicab (king2, sq) - taxicab (king1, sq)); return (s); } static inline int ScoreKBNK (short int winner, short int king1, short int king2) /* Score King+Bishop+Knight versus King endings. This doesn't work all that well but it's better than nothing. */ { register short s, sq, KBNKsq = 0; for (sq = 0; sq < 64; sq++) if (board[sq] == bishop) if (row (sq) % 2 == column (sq) % 2) KBNKsq = 0; else KBNKsq = 7; s = emtl[winner] - 300; if (KBNKsq == 0) s += KBNK[king2]; else s += KBNK[locn (row (king2), 7 - column (king2))]; s -= taxicab (king1, king2); s -= distance (PieceList[winner][1], king2); s -= distance (PieceList[winner][2], king2); return (s); } void ScoreLoneKing (short int side, short int *score) /* Static evaluation when loser has only a king and winner has no pawns or no pieces. */ { register short winner, loser, king1, king2, s, i; UpdateWeights (); if (mtl[white] > mtl[black]) winner = white; else winner = black; loser = otherside[winner]; king1 = PieceList[winner][0]; king2 = PieceList[loser][0]; s = 0; if (pmtl[winner] > 0) for (i = 1; i <= PieceCnt[winner]; i++) s += ScoreKPK (side, winner, loser, king1, king2, PieceList[winner][i]); else if (emtl[winner] == valueB + valueN) s = ScoreKBNK (winner, king1, king2); else if (emtl[winner] > valueB) s = 500 + emtl[winner] - DyingKing[king2] - 2 * distance (king1, king2); if (side == winner) *score = s; else *score = -s; } static inline void BRscan (short int sq, short int *s, short int *mob) /* Find Bishop and Rook mobility, XRAY attacks, and pins. Increment the hung[] array if a pin is found. */ { register short u, piece, pin; register unsigned char *ppos, *pdir; short *Kf; Kf = Kfield[c1]; *mob = 0; piece = board[sq]; ppos = nextpos[piece][sq]; pdir = nextdir[piece][sq]; u = ppos[sq]; pin = -1; /* start new direction */ do { *s += Kf[u]; if (color[u] == neutral) { (*mob)++; if (ppos[u] == pdir[u]) pin = -1; /* oops new direction */ u = ppos[u]; } else if (pin < 0) { if (board[u] == pawn || board[u] == king) u = pdir[u]; else { if (ppos[u] != pdir[u]) pin = u; /* not on the edge and on to find a pin */ u = ppos[u]; } } else { if (color[u] == c2 && (board[u] > piece || atk2[u] == 0)) { if (color[pin] == c2) { *s += PINVAL; if (atk2[pin] == 0 || atk1[pin] > control[board[pin]] + 1) ++hung[c2]; } else *s += XRAY; } pin = -1; /* new direction */ u = pdir[u]; } } while (u != sq); } static inline void KingScan (short int sq, short int *s) /* Assign penalties if king can be threatened by checks, if squares near the king are controlled by the enemy (especially the queen), or if there are no pawns near the king. The following must be true: board[sq] == king c1 == color[sq] c2 == otherside[c1] */ #define ScoreThreat \ if (color[u] != c2)\ if (atk1[u] == 0 || (atk2[u] & 0xFF) > 1) ++cnt;\ else *s -= 3 { register short u; register unsigned char *ppos, *pdir; register short cnt, ok; cnt = 0; if (HasBishop[c2] || HasQueen[c2]) { ppos = nextpos[bishop][sq]; pdir = nextdir[bishop][sq]; u = ppos[sq]; do { if (atk2[u] & ctlBQ) ScoreThreat; u = (color[u] == neutral) ? ppos[u] : pdir[u]; } while (u != sq); } if (HasRook[c2] || HasQueen[c2]) { ppos = nextpos[rook][sq]; pdir = nextdir[rook][sq]; u = ppos[sq]; do { if (atk2[u] & ctlRQ) ScoreThreat; u = (color[u] == neutral) ? ppos[u] : pdir[u]; } while (u != sq); } if (HasKnight[c2]) { pdir = nextdir[knight][sq]; u = pdir[sq]; do { if (atk2[u] & ctlNN) ScoreThreat; u = pdir[u]; } while (u != sq); } *s += (KSFTY * KTHRT[cnt]) / 16; cnt = 0; ok = false; pdir = nextpos[king][sq]; u = pdir[sq]; do { if (board[u] == pawn) ok = true; if (atk2[u] > atk1[u]) { ++cnt; if (atk2[u] & ctlQ) if (atk2[u] > ctlQ + 1 && atk1[u] < ctlQ) *s -= 4 * KSFTY; } u = pdir[u]; } while (u != sq); if (!ok) *s -= KSFTY; if (cnt > 1) *s -= KSFTY; } static inline int trapped (short int sq) /* See if the attacked piece has unattacked squares to move to. The following must be true: c1 == color[sq] c2 == otherside[c1] */ { register short u, piece; register unsigned char *ppos, *pdir; piece = board[sq]; ppos = nextpos[ptype[c1][piece]][sq]; pdir = nextdir[ptype[c1][piece]][sq]; if (piece == pawn) { u = ppos[sq]; /* follow no captures thread */ if (color[u] == neutral) { if (atk1[u] >= atk2[u]) return (false); if (atk2[u] < ctlP) { u = ppos[u]; if (color[u] == neutral && atk1[u] >= atk2[u]) return (false); } } u = pdir[sq]; /* follow captures thread */ if (color[u] == c2) return (false); u = pdir[u]; if (color[u] == c2) return (false); } else { u = ppos[sq]; do { if (color[u] != c1) if (atk2[u] == 0 || board[u] >= piece) return (false); u = (color[u] == neutral) ? ppos[u] : pdir[u]; } while (u != sq); } return (true); } static inline int PawnValue (short int sq, short int side) /* Calculate the positional value for a pawn on 'sq'. */ { register short j, fyle, rank; register short s, a1, a2, in_square, r, e; a1 = (atk1[sq] & 0x4FFF); a2 = (atk2[sq] & 0x4FFF); rank = row (sq); fyle = column (sq); s = 0; if (c1 == white) { s = Mwpawn[sq]; if ((sq == 11 && color[19] != neutral) || (sq == 12 && color[20] != neutral)) s += PEDRNK2B; if ((fyle == 0 || PC1[fyle - 1] == 0) && (fyle == 7 || PC1[fyle + 1] == 0)) s += ISOLANI[fyle]; else if (PC1[fyle] > 1) s += PDOUBLED; if (a1 < ctlP && atk1[sq + 8] < ctlP) { s += BACKWARD[a2 & 0xFF]; if (PC2[fyle] == 0) s += PWEAKH; if (color[sq + 8] != neutral) s += PBLOK; } if (PC2[fyle] == 0) { if (side == black) r = rank - 1; else r = rank; in_square = (row (bking) >= r && distance (sq, bking) < 8 - r); if (a2 == 0 || side == white) e = 0; else e = 1; for (j = sq + 8; j < 64; j += 8) if (atk2[j] >= ctlP) { e = 2; break; } else if (atk2[j] > 0 || color[j] != neutral) e = 1; if (e == 2) s += (stage * PassedPawn3[rank]) / 10; else if (in_square || e == 1) s += (stage * PassedPawn2[rank]) / 10; else if (emtl[black] > 0) s += (stage * PassedPawn1[rank]) / 10; else s += PassedPawn0[rank]; } } else if (c1 == black) { s = Mbpawn[sq]; if ((sq == 51 && color[43] != neutral) || (sq == 52 && color[44] != neutral)) s += PEDRNK2B; if ((fyle == 0 || PC1[fyle - 1] == 0) && (fyle == 7 || PC1[fyle + 1] == 0)) s += ISOLANI[fyle]; else if (PC1[fyle] > 1) s += PDOUBLED; if (a1 < ctlP && atk1[sq - 8] < ctlP) { s += BACKWARD[a2 & 0xFF]; if (PC2[fyle] == 0) s += PWEAKH; if (color[sq - 8] != neutral) s += PBLOK; } if (PC2[fyle] == 0) { if (side == white) r = rank + 1; else r = rank; in_square = (row (wking) <= r && distance (sq, wking) < r + 1); if (a2 == 0 || side == black) e = 0; else e = 1; for (j = sq - 8; j >= 0; j -= 8) if (atk2[j] >= ctlP) { e = 2; break; } else if (atk2[j] > 0 || color[j] != neutral) e = 1; if (e == 2) s += (stage * PassedPawn3[7 - rank]) / 10; else if (in_square || e == 1) s += (stage * PassedPawn2[7 - rank]) / 10; else if (emtl[white] > 0) s += (stage * PassedPawn1[7 - rank]) / 10; else s += PassedPawn0[7 - rank]; } } if (a2 > 0) { if (a1 == 0 || a2 > ctlP + 1) { s += HUNGP; ++hung[c1]; if (trapped (sq)) ++hung[c1]; } else if (a2 > a1) s += ATAKD; } return (s); } static inline int KnightValue (short int sq, short int side) /* Calculate the positional value for a knight on 'sq'. */ { register short s, a2, a1; s = Mknight[c1][sq]; a2 = (atk2[sq] & 0x4FFF); if (a2 > 0) { a1 = (atk1[sq] & 0x4FFF); if (a1 == 0 || a2 > ctlBN + 1) { s += HUNGP; ++hung[c1]; if (trapped (sq)) ++hung[c1]; } else if (a2 >= ctlBN || a1 < ctlP) s += ATAKD; } return (s); } static inline int BishopValue (short int sq, short int side) /* Calculate the positional value for a bishop on 'sq'. */ { register short a2, a1; short s, mob; s = Mbishop[c1][sq]; BRscan (sq, &s, &mob); s += BMBLTY[mob]; a2 = (atk2[sq] & 0x4FFF); if (a2 > 0) { a1 = (atk1[sq] & 0x4FFF); if (a1 == 0 || a2 > ctlBN + 1) { s += HUNGP; ++hung[c1]; if (trapped (sq)) ++hung[c1]; } else if (a2 >= ctlBN || a1 < ctlP) s += ATAKD; } return (s); } static inline int RookValue (short int sq, short int side) /* Calculate the positional value for a rook on 'sq'. */ { register short fyle, a2, a1; short s, mob; s = RookBonus; BRscan (sq, &s, &mob); s += RMBLTY[mob]; fyle = column (sq); if (PC1[fyle] == 0) s += RHOPN; if (PC2[fyle] == 0) s += RHOPNX; if (pmtl[c2] > 100 && row (sq) == rank7[c1]) s += 10; if (stage > 2) s += 14 - taxicab (sq, EnemyKing); a2 = (atk2[sq] & 0x4FFF); if (a2 > 0) { a1 = (atk1[sq] & 0x4FFF); if (a1 == 0 || a2 > ctlR + 1) { s += HUNGP; ++hung[c1]; if (trapped (sq)) ++hung[c1]; } else if (a2 >= ctlR || a1 < ctlP) s += ATAKD; } return (s); } static inline int QueenValue (short int sq, short int side) /* Calculate the positional value for a queen on 'sq'. */ { register short s, a2, a1; s = (distance (sq, EnemyKing) < 3) ? 12 : 0; if (stage > 2) s += 14 - taxicab (sq, EnemyKing); a2 = (atk2[sq] & 0x4FFF); if (a2 > 0) { a1 = (atk1[sq] & 0x4FFF); if (a1 == 0 || a2 > ctlQ + 1) { s += HUNGP; ++hung[c1]; if (trapped (sq)) ++hung[c1]; } else if (a2 >= ctlQ || a1 < ctlP) s += ATAKD; } return (s); } static inline int KingValue (short int sq, short int side) /* Calculate the positional value for a king on 'sq'. */ { register short fyle, a2, a1; short s; s = Mking[c1][sq]; if (KSFTY > 0) if (Developed[c2] || stage > 0) KingScan (sq, &s); if (castld[c1]) s += KCASTLD; else if (Mvboard[kingP[c1]]) s += KMOVD; fyle = column (sq); if (PC1[fyle] == 0) s += KHOPN; if (PC2[fyle] == 0) s += KHOPNX; switch (fyle) { case 5: if (PC1[7] == 0) s += KHOPN; if (PC2[7] == 0) s += KHOPNX; /* Fall through */ case 4: case 6: case 0: if (PC1[fyle + 1] == 0) s += KHOPN; if (PC2[fyle + 1] == 0) s += KHOPNX; break; case 2: if (PC1[0] == 0) s += KHOPN; if (PC2[0] == 0) s += KHOPNX; /* Fall through */ case 3: case 1: case 7: if (PC1[fyle - 1] == 0) s += KHOPN; if (PC2[fyle - 1] == 0) s += KHOPNX; break; default: /* Impossible! */ break; } a2 = (atk2[sq] & 0x4FFF); if (a2 > 0) { a1 = (atk1[sq] & 0x4FFF); if (a1 == 0 || a2 > ctlK + 1) { s += HUNGP; ++hung[c1]; } else s += ATAKD; } return (s); } void ScorePosition (short int side, short int *score) /* Perform normal static evaluation of board position. A score is generated for each piece and these are summed to get a score for each side. */ { register short sq, s, i, xside; short pscore[2]; UpdateWeights (); xside = otherside[side]; pscore[white] = pscore[black] = 0; for (c1 = white; c1 <= black; c1++) { c2 = otherside[c1]; atk1 = atak[c1]; atk2 = atak[c2]; PC1 = PawnCnt[c1]; PC2 = PawnCnt[c2]; for (i = PieceCnt[c1]; i >= 0; i--) { sq = PieceList[c1][i]; switch (board[sq]) { case pawn: s = PawnValue(sq, side); break; case knight: s = KnightValue(sq, side); break; case bishop: s = BishopValue(sq, side); break; case rook: s = RookValue(sq, side); break; case queen: s = QueenValue(sq, side); break; case king: s = KingValue(sq, side); break; default: s = 0; break; } pscore[c1] += s; svalue[sq] = s; } } if (hung[side] > 1) pscore[side] += HUNGX; if (hung[xside] > 1) pscore[xside] += HUNGX; *score = mtl[side] - mtl[xside] + pscore[side] - pscore[xside] + 10; if (dither) *score += urand () % dither; if (*score > 0 && pmtl[side] == 0) if (emtl[side] < valueR) *score = 0; else if (*score < valueR) *score /= 2; if (*score < 0 && pmtl[xside] == 0) if (emtl[xside] < valueR) *score = 0; else if (-*score < valueR) *score /= 2; if (mtl[xside] == valueK && emtl[side] > valueB) *score += 200; if (mtl[side] == valueK && emtl[xside] > valueB) *score -= 200; } static inline void BlendBoard (const short int a[64], const short int b[64], short int c[64]) { register int sq; for (sq = 0; sq < 64; sq++) c[sq] = (a[sq] * (10 - stage) + b[sq] * stage) / 10; } static inline void CopyBoard (const short int a[64], short int b[64]) { register int sq; for (sq = 0; sq < 64; sq++) b[sq] = a[sq]; } void ExaminePosition (void) /* This is done one time before the search is started. Set up arrays Mwpawn, Mbpawn, Mknight, Mbishop, Mking which are used in the SqValue() function to determine the positional value of each piece. */ { register short i, sq; short wpadv, bpadv, wstrong, bstrong, z, side, pp, j, k, val, Pd, fyle, rank; static short PawnStorm = false; ataks (white, atak[white]); ataks (black, atak[black]); UpdateWeights (); HasKnight[white] = HasKnight[black] = 0; HasBishop[white] = HasBishop[black] = 0; HasRook[white] = HasRook[black] = 0; HasQueen[white] = HasQueen[black] = 0; for (side = white; side <= black; side++) for (i = PieceCnt[side]; i >= 0; i--) switch (board[PieceList[side][i]]) { case knight: ++HasKnight[side]; break; case bishop: ++HasBishop[side]; break; case rook: ++HasRook[side]; break; case queen: ++HasQueen[side]; break; } if (!Developed[white]) Developed[white] = (board[1] != knight && board[2] != bishop && board[5] != bishop && board[6] != knight); if (!Developed[black]) Developed[black] = (board[57] != knight && board[58] != bishop && board[61] != bishop && board[62] != knight); if (!PawnStorm && stage < 5) PawnStorm = ((column (wking) < 3 && column (bking) > 4) || (column (wking) > 4 && column (bking) < 3)); CopyBoard (pknight, Mknight[white]); CopyBoard (pknight, Mknight[black]); CopyBoard (pbishop, Mbishop[white]); CopyBoard (pbishop, Mbishop[black]); BlendBoard (KingOpening, KingEnding, Mking[white]); BlendBoard (KingOpening, KingEnding, Mking[black]); for (sq = 0; sq < 64; sq++) { fyle = column (sq); rank = row (sq); wstrong = bstrong = true; for (i = sq; i < 64; i += 8) if (Patak (black, i)) { wstrong = false; break; } for (i = sq; i >= 0; i -= 8) if (Patak (white, i)) { bstrong = false; break; } wpadv = bpadv = PADVNCM; if ((fyle == 0 || PawnCnt[white][fyle - 1] == 0) && (fyle == 7 || PawnCnt[white][fyle + 1] == 0)) wpadv = PADVNCI; if ((fyle == 0 || PawnCnt[black][fyle - 1] == 0) && (fyle == 7 || PawnCnt[black][fyle + 1] == 0)) bpadv = PADVNCI; Mwpawn[sq] = (wpadv * PawnAdvance[sq]) / 10; Mbpawn[sq] = (bpadv * PawnAdvance[63 - sq]) / 10; Mwpawn[sq] += PawnBonus; Mbpawn[sq] += PawnBonus; if (Mvboard[kingP[white]]) { if ((fyle < 3 || fyle > 4) && distance (sq, wking) < 3) Mwpawn[sq] += PAWNSHIELD; } else if (rank < 3 && (fyle < 2 || fyle > 5)) Mwpawn[sq] += PAWNSHIELD / 2; if (Mvboard[kingP[black]]) { if ((fyle < 3 || fyle > 4) && distance (sq, bking) < 3) Mbpawn[sq] += PAWNSHIELD; } else if (rank > 4 && (fyle < 2 || fyle > 5)) Mbpawn[sq] += PAWNSHIELD / 2; if (PawnStorm) { if ((column (wking) < 4 && fyle > 4) || (column (wking) > 3 && fyle < 3)) Mwpawn[sq] += 3 * rank - 21; if ((column (bking) < 4 && fyle > 4) || (column (bking) > 3 && fyle < 3)) Mbpawn[sq] -= 3 * rank; } Mknight[white][sq] += 5 - distance (sq, bking); Mknight[white][sq] += 5 - distance (sq, wking); Mknight[black][sq] += 5 - distance (sq, wking); Mknight[black][sq] += 5 - distance (sq, bking); Mbishop[white][sq] += BishopBonus; Mbishop[black][sq] += BishopBonus; for (i = PieceCnt[black]; i >= 0; i--) if (distance (sq, PieceList[black][i]) < 3) Mknight[white][sq] += KNIGHTPOST; for (i = PieceCnt[white]; i >= 0; i--) if (distance (sq, PieceList[white][i]) < 3) Mknight[black][sq] += KNIGHTPOST; if (wstrong) Mknight[white][sq] += KNIGHTSTRONG; if (bstrong) Mknight[black][sq] += KNIGHTSTRONG; if (wstrong) Mbishop[white][sq] += BISHOPSTRONG; if (bstrong) Mbishop[black][sq] += BISHOPSTRONG; if (HasBishop[white] == 2) Mbishop[white][sq] += 8; if (HasBishop[black] == 2) Mbishop[black][sq] += 8; if (HasKnight[white] == 2) Mknight[white][sq] += 5; if (HasKnight[black] == 2) Mknight[black][sq] += 5; Kfield[white][sq] = Kfield[black][sq] = 0; if (distance (sq, wking) == 1) Kfield[black][sq] = KATAK; if (distance (sq, bking) == 1) Kfield[white][sq] = KATAK; Pd = 0; for (k = 0; k <= PieceCnt[white]; k++) { i = PieceList[white][k]; if (board[i] == pawn) { pp = true; if (row (i) == 6) z = i + 8; else z = i + 16; for (j = i + 8; j < 64; j += 8) if (Patak (black, j) || board[j] == pawn) { pp = false; break; } if (pp) Pd += 5 * taxicab (sq, z); else Pd += taxicab (sq, z); } } for (k = 0; k <= PieceCnt[black]; k++) { i = PieceList[black][k]; if (board[i] == pawn) { pp = true; if (row (i) == 1) z = i - 8; else z = i - 16; for (j = i - 8; j >= 0; j -= 8) if (Patak (white, j) || board[j] == pawn) { pp = false; break; } if (pp) Pd += 5 * taxicab (sq, z); else Pd += taxicab (sq, z); } } if (Pd != 0) { val = (Pd * stage2) / 10; Mking[white][sq] -= val; Mking[black][sq] -= val; } } } void UpdateWeights (void) /* If material balance has changed, determine the values for the positional evaluation terms. */ { register short tmtl, s1; emtl[white] = mtl[white] - pmtl[white] - valueK; emtl[black] = mtl[black] - pmtl[black] - valueK; tmtl = emtl[white] + emtl[black]; s1 = (tmtl > 6600) ? 0 : ((tmtl < 1400) ? 10 : (6600 - tmtl) / 520); if (s1 != stage) { stage = s1; stage2 = (tmtl > 3600) ? 0 : ((tmtl < 1400) ? 10 : (3600 - tmtl) / 220); PEDRNK2B = -15; /* centre pawn on 2nd rank & blocked */ PBLOK = -4; /* blocked backward pawn */ PDOUBLED = -14; /* doubled pawn */ PWEAKH = -4; /* weak pawn on half open file */ PAWNSHIELD = 10 - stage; /* pawn near friendly king */ PADVNCM = 10; /* advanced pawn multiplier */ PADVNCI = 7; /* muliplier for isolated pawn */ PawnBonus = stage; KNIGHTPOST = (stage + 2) / 3; /* knight near enemy pieces */ KNIGHTSTRONG = (stage + 6) / 2; /* occupies pawn hole */ BISHOPSTRONG = (stage + 6) / 2; /* occupies pawn hole */ BishopBonus = 2 * stage; RHOPN = 10; /* rook on half open file */ RHOPNX = 4; RookBonus = 6 * stage; XRAY = 8; /* Xray attack on piece */ PINVAL = 10; /* Pin */ KHOPN = (3 * stage - 30) / 2; /* king on half open file */ KHOPNX = KHOPN / 2; KCASTLD = 10 - stage; KMOVD = -40 / (stage + 1); /* king moved before castling */ KATAK = (10 - stage) / 2; /* B,R attacks near enemy king */ if (stage < 8) KSFTY = 16 - 2 * stage; else KSFTY = 0; ATAKD = -6; /* defender > attacker */ HUNGP = -8; /* each hung piece */ HUNGX = -12; /* extra for >1 hung piece */ } }