/* * search.c - C source for GNU CHESS * * Copyright (c) 1988,1989,1990 John Stanback Copyright (c) 1992 Free Software * Foundation * * This file is part of GNU CHESS. * * GNU Chess is free software; you can redistribute it and/or modify it under * the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2, or (at your option) any later * version. * * GNU Chess is distributed in the hope that it will be useful, but WITHOUT ANY * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License along with * GNU Chess; see the file COPYING. If not, write to the Free Software * Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "gnuchess.h" #ifdef QUIETBACKGROUND short background = 0; #endif /* QUIETBACKGROUND */ static short int DepthBeyond; unsigned short int PrVar[MAXDEPTH]; extern short int ISZERO; extern char mvstr[4][6]; extern short int recycle; extern int trying_again; #ifdef NULLMOVE short int null; /* Null-move already made or not */ short int PVari; /* Is this the PV */ #endif #ifdef DEBUG40 extern int whichway; #endif #ifdef DEBUG unsigned short DBLINE[MAXDEPTH]; struct leaf *dbptr; #endif short int zwndw; #include "ataks3.h" #define __USE_SYSBASE #include extern int global_tmp_score; extern int previous_score; int Sdepth2=0; extern int MoveNowOK; extern int procpri; extern struct Process *myproc; int Castled[2]={0,0}; int myEnPassant[2]={0,0}; inline short int repetition (void); #include "debug41.h" /* ............ MOVE GENERATION & SEARCH ROUTINES .............. */ inline short int repetition () /* Check for draw by threefold repetition. */ { register short i, c,cnt; register unsigned short m; short b[64]; cnt = c = 0; /* try to avoid work */ if (GameCnt > Game50 + 2) { #if defined(NOMEMSET) || defined(MSDOS) for (i = 0; i < 64; b[i++] = 0); #else memset ((char *) b, 0, (unsigned long)sizeof (b)); #endif /* NOMEMSET */ for (i = GameCnt; i >= Game50; i--) { m = GameList[i].gmove; /* does piece exist on diff board? */ if (b[m & 0xff]) { /* does diffs cancel out, piece back? */ if ((b[m >> 8] += b[m & 0xff]) == 0) --c; b[m & 0xff] = 0; } else { /* create diff */ ++c; /* does diff cancel out another diff? */ if (!(b[m >> 8] -= (b[m & 0xff] = board[m & 0xff] + (color[m & 0xff] << 8)))) --c;; } /* if diff count is 0 we have a repetition */ if (c == 0) if ((i ^ GameCnt) & 1) cnt++; } } return cnt; } int plyscore, globalscore; int 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 struct leaf *p, *q, *r, *k; register s0; struct leaf temp; k = p = &Tree[p1]; q = &Tree[p2]; s0 = p->score; for (r = p + 1; r <= q; r++) if ((r->score) > s0) { s0 = (r->score); p = r; } if (p != k) { temp = *p; *p = *k; *k = temp; return true; } return false; } #ifdef DEBUG unsigned short trace[MAXDEPTH]; char traceline[256]; unsigned short tracelog[MAXDEPTH]; int tracen = 0; int traceflag = 0; int traceply = 0; #endif int bookflag = false; static int TCcount, TCleft; 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 * -Awindow to +Bwindow 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 int i, tempb, tempc, tempsf, tempst, xside, rpt; static short int alpha, beta, score; static struct GameRec *g; int Jscore = 0; int earlyflag; char mystr[16]; #ifdef DEBUG if(debuglevel & (512|1024)){ char b[32]; short c1,c2,r1,r2; tracen=0; traceflag = false; traceply = 0; tracelog[0]=0; while(true){ printf("debug?"); gets(b); if(b[0] == 'p')traceply = atoi(&b[1]); else if(b[0] == '\0')break; else{ c1 = b[0] - 'a'; r1 = b[1] - '1'; c2 = b[2] - 'a'; r2 = b[3] - '1'; trace[++tracen] = (locn (r1, c1) << 8) | locn (r2, c2); } if(tracen == 0 && traceply >0)traceflag = true; } } #endif flag.timeout = false; flag.back = flag.musttimeout = false; xside = side ^ 1; recycle = (GameCnt % rehash) - rehash; /* if background mode set to infinite */ if (iop == 2) { (void)SetTaskPri((struct Task *)myproc,0); ResponseTime = 9999999; #ifdef QUIETBACKGROUND background = true; #endif /* QUIETBACKGROUND */ } else { player = side; if (TCflag) { TCcount = 0; #ifdef QUIETBACKGROUND background = false; #endif /* QUIETBACKGROUND */ if (TimeControl.moves[side] < 1) TimeControl.moves[side] = 1; /* special case time per move specified */ if (flag.onemove) { ResponseTime = TimeControl.clock[side] - 100; TCleft = 0; } else { /* calculate avg time per move remaining */ TimeControl.clock[side] += TCadd; ResponseTime = (TimeControl.clock[side]) / (((TimeControl.moves[side]) * 2) + 1); TCleft = (int)ResponseTime / 3; ResponseTime += TCadd/2; if (TimeControl.moves[side] < 5) TCcount = MAXTCCOUNTX - 1; } if (ResponseTime < 100) { ResponseTime = 100; TCcount = MAXTCCOUNTX; } else if (ResponseTime < 200) { TCcount = MAXTCCOUNTX - 1; } } else { #ifdef QUIETBACKGROUND background = false; #endif /* QUIETBACKGROUND */ ResponseTime = MaxResponseTime; } if (TCleft) { TCcount = ((int)((TimeControl.clock[side] - ResponseTime)) / 2) / TCleft; if (TCcount > MAXTCCOUNTX) TCcount = 0; else TCcount = MAXTCCOUNTX - TCcount; } else TCcount = MAXTCCOUNTX; } if (MoveNowOK) { thinking2 = 1; /* allow move now menu item to work */ } else { thinking2 = 0; /* do not allow move now menu item to work */ } ExtraTime = 0; ExaminePosition (); score = ScorePosition (side); #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowSidetoMove (); #ifdef notdef if (TCflag && TCcount < MAXTCCOUNT) if (score < SCORETIME) { ExtraTime += TCleft; TCcount++; } #endif #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ SearchStartStuff (side); #ifdef HISTORY #if defined(NOMEMSET) || defined(MSDOS) for (i = 0; i < 32768; i++) history[i] = 0; #else memset ((unsigned char *) history, 0, (unsigned long)sizeof (history)); #endif /* NOMEMSET */ #endif FROMsquare = TOsquare = -1; PV = 0; if (iop == 1) hint = 0; for (i = 0; i < MAXDEPTH; i++) PrVar[i] = killr0[i] = killr1[i] = killr2[i] = killr3[i] = 0; /* set initial window for search */ alpha = score - ((computer == black) ? BAwindow : WAwindow); beta = score + ((computer == black) ? BBwindow : WBwindow); rpt = 0; TrPnt[1] = 0; root = &Tree[0]; MoveList (side, 1); for (i = TrPnt[1]; i < TrPnt[2]; i++) if (!pick (i, TrPnt[2] - 1)) break; /* can I get a book move? */ if (flag.regularstart && Book) { flag.timeout = bookflag = OpeningBook (&hint, side); if (TCflag) ResponseTime += ResponseTime; } /* zero stats for hash table */ reminus = replus = 0; GenCnt = NodeCnt = ETnodes = EvalNodes = HashCnt = FHashAdd = HashAdd = FHashCnt = THashCol = HashCol = 0; globalscore = plyscore = score; zwndw = 20; trying_again = global_tmp_score = previous_score = 0; #include "debug4.h" /********************* main loop ********************************/ Sdepth = (MaxSearchDepth<(MINDEPTH-1))?MaxSearchDepth:(MINDEPTH-1); /*printf("\n\n");*/ while (!flag.timeout) { /*printf("time0 = %d et = %d SDepth = %d GameCnt = %d\n",time0, et,Sdepth,GameCnt);*/ /*printf("ThinkAheadWorked = %d ThinkAheadDepth = %d\n",ThinkAheadWorked,ThinkAheadDepth);*/ /* go down a level at a time */ Sdepth++; #ifdef NULLMOVE null = 0; PVari = 1; #endif DepthBeyond = Sdepth + ((Sdepth == 1) ? 7 : 11); #if !defined CHESSTOOL && !defined XBOARD #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowDepth (' '); #endif /* search at this level returns score of PV */ score = search (side, 1, Sdepth, alpha, beta, PrVar, &rpt); /* save PV as killer */ for (i = 1; i <= Sdepth; i++) killr0[i] = PrVar[i]; /* low search failure re-search with (-inf,score) limits */ if (score < alpha) { #if !defined CHESSTOOL && !defined XBOARD reminus++; #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowDepth ('-'); #endif if (TCflag && TCcount < MAXTCCOUNTR) { TCcount = MAXTCCOUNTR - 1; ExtraTime += (8 * TCleft); } score = search (side, 1, Sdepth, -9999, score, PrVar, &rpt); } /* high search failure re-search with (score, +inf) limits */ if (score > beta && !(root->flags & exact)) { #if !defined CHESSTOOL && !defined XBOARD replus++; #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowDepth ('+'); #endif score = search (side, 1, Sdepth, score, 9999, PrVar, &rpt); } /**************** out of search ********************************************/ if ((flag.timeout)||(flag.musttimeout)||(flag.back)) earlyflag = true; else earlyflag = false; if (flag.musttimeout || Sdepth >= MaxSearchDepth) { flag.timeout = true; } else if (TCflag && (Sdepth > (MINDEPTH - 1)) && (TCcount < MAXTCCOUNTR)) { if (killr0[1] != PrVar[1] /* || Killr0[2] != PrVar[2] */ ) { TCcount++; ExtraTime += TCleft; } if ((abs (score - globalscore) / Sdepth) > ZDELTA) { TCcount++; ExtraTime += TCleft; } } if (score > (Jscore - zwndw) && score > (Tree[1].score + 250)) ExtraTime = 0; /*printf("sdepth = %d mindepth = %d TCflag = %d \n4*et = %d respt = %d extra = %d\n",Sdepth,MINDEPTH,TCflag,4*et,ResponseTime,ExtraTime);*/ if (root->flags & exact) flag.timeout = true; /*else if (Tree[1].score < -9000) flag.timeout = true;*/ else if (!(Sdepth < MINDEPTH) && TCflag && ((4 * et) > (2*ResponseTime + ExtraTime))) flag.timeout = true; /************************ time control ***********************************/ /* save PV as killer */ for (i = 1; i <= Sdepth + 1; i++) killr0[i] = PrVar[i]; if (!flag.timeout) Tscore[0] = score; /* if (!flag.timeout) */ for (i = TrPnt[1]+1; i < TrPnt[2]; i++) if (!pick (i, TrPnt[2] - 1)) break; /* if done or nothing good to look at quit */ if ((root->flags & exact) || (score < -9000)) flag.timeout = true; /* find the next best move put below root */ #include "debug13.h" if (!flag.timeout) { /* */ #if !defined NODYNALPHA Jscore = (plyscore + score) >> 1; #endif zwndw = 20 + abs (Jscore / 12); plyscore = score; /* recompute search window */ beta = score + ((computer == black) ? BBwindow : WBwindow); #if !defined NODYNALPHA alpha = ((Jscore < score) ? Jscore : score) - ((computer == black) ? BAwindow : WAwindow) - zwndw; #else alpha = score - ((computer == black) ? BAwindow : WAwindow); #endif } #if !defined CHESSTOOL && !defined XBOARD #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowResults (score, PrVar, '.'); #ifdef DEBUG41 debug41 (score, PrVar, '.'); #endif #endif #include "debug16.h" if (((!PrVar[1])||(!PrVar[2]))&&(!(root->flags & exact))&&(iop != 2)&&(abs(score) < 9000)) /* do not trust this move! */ { if (Sdepth > 2) { if (earlyflag) { Sdepth--; } if (!trying_again) { /* this is first bogus move we have seen */ ResponseTime = ResponseTime << 1; ExtraTime += 251; } else { /* this is not 1st bogus move we have seen */ ExtraTime += 201; } trying_again = 1; flag.timeout = false; flag.back = false; flag.musttimeout = false; } } else if (trying_again) /* this move is trustworthy, to an extent */ { if ((TCflag && ((4 * et) > (ResponseTime + ExtraTime - 251)))||(root->flags & exact)) flag.timeout = true; } previous_score = score; } /* while !flag.timeout */ /******************************* end of main loop ***********************************/ /* background mode */ if (iop == 2) { if (!flag.easy) { Sdepth2 = Sdepth; if (Sdepth2 > (GlobalTgtDepth+1)) Sdepth2--; } return; } #include "debug4.h" if (rpt >= 2) { root->flags |= draw; DRAW = CP[101]; /* Repetition */ } else /* if no moves and not in check then draw */ if ((score == -9999) && !(SqAtakd3 (PieceList[side][0], xside))) { root->flags |= draw; DRAW = CP[87]; /* No moves */ } else if (GameCnt == MAXMOVES) { root->flags |= draw; DRAW = CP[80]; /* Max Moves */ } /* not in book so set hint to guessed move for other side */ if (!bookflag) hint = ((PrVar[1]) ? PrVar[2] : 0); /* if not mate or draw make move and output it */ if (((score > -9999) && (rpt <= 2)) || (root->flags & draw)) { MakeMove (side, &Tree[0], &tempb, &tempc, &tempsf, &tempst, &INCscore); #if !defined NOMATERIAL if (flag.material && !pmtl[black] && !pmtl[white] && (mtl[white] < (valueR + valueK)) && (mtl[black] < (valueR + valueK))) { root->flags |= draw; DRAW = CP[224]; /* No pieces */ } else #endif if (!PieceCnt[black] && !PieceCnt[white]) { root->flags |= draw; DRAW = CP[88]; /* No pieces */ } algbr (root->f, root->t, (short) root->flags); } else { algbr (0, 0, 0); /* Zero move string when mate. */ root->score = score; /* When mate, ignore distinctions! * --SMC */ } g = &GameList[GameCnt]; if (g->flags & capture && g->piece == king) { flag.mate = flag.illegal = true; } /* If Time Control get the elapsed time */ if (TCflag) ElapsedTime (1); OutputMove (mystr); /* if mate set flag */ if ((score == -9999 || score == 9998)) flag.mate = true; /* if mate clear hint */ if (flag.mate) hint = 0; /* if pawn move or capture or castle or promote zero repitition array */ if ((board[root->t] == pawn) || (root->flags & (capture | cstlmask | promote))) { Game50 = GameCnt; ZeroRPT (); } /* add move to game list */ g->score = score; g->nodes = NodeCnt; g->time = (et +50)/100; g->depth = Sdepth; #include "debug40.h" /* update time comtrol info */ if (TCflag) { #if defined CHESSTOOL || defined XBOARD TimeControl.clock[side] -= (et + OperatorTime + 45); timecomp[compptr] = (et + OperatorTime + 45); #else TimeControl.clock[side] -= (et + OperatorTime); timecomp[compptr] = (et + OperatorTime); #endif /* finished our required moves - setup the next set */ --TimeControl.moves[side]; } /* check for end conditions */ if ((root->flags & draw) /* && flag.bothsides */ ) #if !defined CLIENT flag.mate = true; #else ; #endif else if (GameCnt == MAXMOVES) { flag.mate = true; } /* out of move store, you loose */ else /* switch to other side */ player = xside; Sdepth = 0; } int search (short int side, register short int ply, register short int depth, short int alpha, short int beta, short unsigned 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. */ { register short j, pnt; short tempb, tempc, tempsf, tempst; short xside, pbst, score, rcnt, InChk; unsigned short mv, nxtline[MAXDEPTH]; struct leaf *node, tmp; short best = -12000; short bestwidth = 0; #ifdef NULLMOVE #ifndef AMIGA short int PVsave; #endif short int PVarisave; #endif #ifdef DEBUG int xxxtmp; int tracetmp; #endif NodeCnt++; /* look every ZNODE nodes for a timeout */ if (!null && NodeCnt > ETnodes ) { ElapsedTime (2); if (flag.back) { flag.back = false; flag.timeout = true; flag.musttimeout = false; } else if (TCflag || MaxResponseTime) { if ((et >= (ResponseTime + ExtraTime)) && Sdepth > MINDEPTH && abs(best) < 10000) { /* try to extend to finish ply */ #define TRYEXTEND 1 #ifdef TRYEXTEND if ((TCflag && TCcount < MAXTCCOUNTX)&&(GameCnt > 29)) { flag.musttimeout = true; TCcount += 1; ExtraTime += TCleft; } else { flag.timeout = true; flag.musttimeout = false; } #else if ((TCflag && TCcount < MAXTCCOUNTX)&&(flag.easy)) { flag.musttimeout = true; TCcount += 1; ExtraTime += TCleft; } else { flag.timeout = true; flag.musttimeout = false; } #endif } } } else if (!TCflag && flag.musttimeout && Sdepth > MINDEPTH) { flag.timeout = true; flag.musttimeout = false; } xside = side ^ 1; /* slk is lone king indicator for either side */ score = evaluate (side, ply, alpha, beta, INCscore, &InChk); /* * check for possible repitition if so call repitition - rpt is * repeat count */ if ((ply <= Sdepth + 3) && rpthash[side][hashkey & 0xFF] > 0) { *rpt = repetition (); /* * repeat position >2 don't need to return score it's taken * care of above */ if (*rpt == 1) score /= 2; } else *rpt = 0; /* score > 9000 its a draw or mate */ if (score > 9000) { bstline[ply] = 0; return (score); } /* Do we need to add depth because of special conditions */ /* if in check or pawn threat or in capture sequence search deeper */ /*************************************** depth extensions ***********************************/ if (depth > 0) { /* Allow opponent a chance to check again */ if (InChk) depth = (depth < 2) ? 2 : depth; else if (PawnThreat[ply - 1] || (flag.rcptr && (score > alpha) && (score < beta) && (ply > 2) && CptrFlag[ply - 1] && CptrFlag[ply - 2])) ++depth; } else { if (score >= alpha && (InChk || PawnThreat[ply - 1] || (hung[side] > 1 && ply == Sdepth + 1))) depth = 1; else if (score <= beta && ((ply < Sdepth + 4) && (ply > 4) && ChkFlag[ply - 2] && ChkFlag[ply - 4] && ChkFlag[ply - 2] != ChkFlag[ply - 4])) depth = 1; } /*******************************************************************************************/ /* try the local transition table if it's there */ #if ttblsz if (/*depth > 0 &&*/ flag.hash && ply > 1) { if (ProbeTTable (side, depth, ply, &alpha, &beta, &score) == true) { bstline[ply] = PV; bstline[ply + 1] = 0; #include "debug64.h" if (beta == -20000) return (score); if (alpha > beta) return (alpha); } #ifdef HASHFILE /* ok try the transition file if its there */ else if (hashfile && (depth > HashDepth) && (GameCnt < HashMoveLimit) && (ProbeFTable (side, depth, ply, &alpha, &beta, &score) == true)) { #ifdef notdef int hgood = false; int f = PV >> 8; int t = PV & 0x3f; register int i; /* * if you find something put it in the local table * for future reference */ hgood = false; for (i = TrPnt[ply]; i < TrPnt[ply + 1]; i++) { if (Tree[i].f == f && Tree[i].t == t) { hgood = true; break; } } if (hgood) { #endif PutInTTable (side, score, depth, ply, alpha, beta, PV); bstline[ply] = PV; bstline[ply + 1] = 0; if (beta == -20000) return (score); if (alpha > beta) return (alpha); #ifdef notdef } #endif #include "debug10.h" } #endif /* HASHFILE */ } #endif /* ttblsz */ /* * if more then DepthBeyond ply past goal depth or at goal depth and * score > beta quit - means we are out of the window */ if (ply > DepthBeyond || (depth < 1 && score > beta)) { return (score); } /* * if below first ply and not at goal depth generate all moves else * only capture moves */ if (ply > 1) if (depth > 0 || ply<(SDEPTHLIM)|| (background && ply0)?-12000:score; #ifdef NULLMOVE PVarisave = PVari; if (!null && /* no previous null-move */ !PVari && /* no null-move during the PV */ (ply > 1) & /* not at ply 1 */ (depth > 1) && /* not during the quienscesearch */ !InChk && /* no check */ ((mtl[side] + mtl[xside]) > 4000)) /* enough material such that zugzwang is unlike but who knows which value is suitable? */ { /* ok, we make a null move, i.e. this means we have nothing to do but we have to keep the some arrays up to date otherwise gnuchess gets confused. Maybe somebody knows exactly which informations are important and which not. Another idea is that we try the null-move first and generate the moves later. This may save time but we have to take care that PV and other variables contain the right value so that the move ordering works right. */ register struct GameRec *g; nxtline[ply + 1] = 0; CptrFlag[ply] = 0; PawnThreat[ply] = 0; Tscore[ply] = score; /*PVsave = PV; PV = 0;*/ null = 1; g = &GameList[++GameCnt]; g->hashkey = hashkey; g->hashbd = hashbd; epsquare = -1; TOsquare = -1; g->Game50 = Game50; #ifdef LONGINTS g->gmove = 0xffffffff; #else g->gmove = 0xffff; #endif g->flags = 0; g->piece = 0; g->color = neutral; best = -search(xside, ply+1, depth - 2, -beta-1, -beta, nxtline,&rcnt); null = 0; /*PV = PVsave;*/ GameCnt--; if (best > beta) return (best); else best = -12000; } #endif /* if best so far is better than alpha set alpha to best */ if(best>alpha)alpha=best; /********************** main loop ************************************************************************/ /* look at each move until no more or beta cutoff */ for (pnt = pbst = TrPnt[ply]; pnt < TrPnt[ply + 1] && best <= beta; pnt++) { /* find the most interesting looking of the remaining moves */ if (ply > 1) pick (pnt, TrPnt[ply + 1] - 1); #ifdef NULLMOVE PVari = PVarisave && (pnt == TrPnt[ply]); /* Is this the PV? */ #endif node = &Tree[pnt]; /* is this a forbidden move */ if (ply == 1 && node->score == -32768) continue; #ifdef DEBUG if(debuglevel & (512 | 1024)){ if(!tracen)traceflag = ((ply >traceply)?false:true); else if(ply <= tracen && (ply ==1 || traceflag)) { if(trace[ply] == (Tree[pnt].t |(Tree[pnt].f<<8))) traceflag = true; else traceflag = false; } tracelog[ply] = (Tree[pnt].t |(Tree[pnt].f<<8)); tracelog[ply+1] = 0; } #endif nxtline[ply + 1] = 0; #if !defined CHESSTOOL && !defined XBOARD /* if at top level */ if (ply == 1) { /* at the top update search status */ if (flag.post) #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ ShowCurrentMove (pnt, node->f, node->t); } #endif if (!(node->flags & exact)) { /* make the move and go deeper */ 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; #ifdef DEBUG xxxtmp = node->score; tracetmp = traceflag; #endif node->score = -search (xside, ply + 1, (depth > 0)?depth-1:0, -beta, -alpha, nxtline, &rcnt); node->width = (ply % 2 == 1) ? (TrPnt[ply + 2] - TrPnt[ply + 1]) : 0; if (abs (node->score) > 9000) node->flags |= exact; else if (rcnt == 1) node->score /= 2; #include "debug256.h" if ((rcnt >= 2 || GameCnt - Game50 > 99 || (node->score == 9999 - ply && !ChkFlag[ply]))) { node->flags |= (draw | exact); DRAW = CP[58]; /* Draw */ node->score = ((side == computer) ? contempt : -contempt); } node->reply = nxtline[ply + 1]; /* reset to try next move */ UnmakeMove (side, node, &tempb, &tempc, &tempsf, &tempst); } /* if best move so far */ if (!flag.timeout && ((node->score > best) || ((node->score == best) && (node->width > bestwidth)))) { /* * all things being equal pick the denser part of the * tree */ bestwidth = node->width; /* * if not at goal depth and better than alpha and not * an exact score increment by depth */ if (depth > 0 && node->score > alpha && !(node->flags & exact)) node->score += depth; best = node->score; pbst = pnt; if (best > alpha) { alpha = best; } /* update best line */ for (j = ply + 1; nxtline[j] > 0; j++) bstline[j] = nxtline[j]; bstline[j] = 0; bstline[ply] = (node->f << 8) | node->t; /* if at the top */ if (ply == 1) { /* * if its better than the root score make it * the root */ if ((best > root->score) || ((best == root->score) && (bestwidth > root->width))) { tmp = Tree[pnt]; for (j = pnt - 1; j >= 0; j--) Tree[j + 1] = Tree[j]; Tree[0] = tmp; pbst = 0; } #if !defined CHESSTOOL && !defined XBOARD #ifdef QUIETBACKGROUND if (!background) #endif /* QUIETBACKGROUND */ if (Sdepth > 2) if (best > beta) { global_tmp_score = best; ShowResults (best, bstline, '+'); #ifdef DEBUG41 debug41 (best, bstline, '+'); #endif } else if (best < alpha) { global_tmp_score = best; ShowResults (best, bstline, '-'); #ifdef DEBUG41 debug41 (best, bstline, '-'); #endif } else { global_tmp_score = best; ShowResults (best, bstline, '&'); } #ifdef DEBUG41 debug41 (best, bstline, '&'); #endif #else if(!background && Sdepth >2 && best < alpha){ ExtraTime=8*TCleft; } #endif } } if (flag.timeout) { return (Tscore[ply - 1]); } } /******************************************************************************************/ node = &Tree[pbst]; mv = (node->f << 8) | node->t; #ifdef NULLMOVE PVari = PVarisave; #endif #ifdef DEBUG #include "debug512.h" #endif /* * we have a move so put it in local table - if it's already there * done else if not there or needs to be updated also put it in * hashfile */ #if ttblsz if (flag.hash && ply <= Sdepth && *rpt == 0 && best == alpha) { #ifdef notdef algbr(node->f,node->t,0); printf("IN-> %lx %lx %d %d %s\n",hashkey,hashbd,depth,side,mvstr[0]); #endif if (PutInTTable (side, best, depth, ply, alpha, beta, mv) #ifdef HASHFILE && hashfile && (depth > HashDepth) && (GameCnt < HashMoveLimit)) { #ifdef notdef printf("FT %d %d %d %x\n",side,best,depth,mv); #endif PutInFTable (side, best, depth, ply, alpha, beta, node->f, node->t); } #else ); #endif /* HASHFILE */ } #endif /* ttblsz */ if (depth > 0) { #ifdef HISTORY j = (node->f << 6) | node->t; if (side == black) j |= 0x4000; /*TMPif (j > 32767) { printf("\nBAD HISTORY GUY BAD BAD BAD!!\n");getchar(); }*/ if (history[j] < HISTORYLIM) history[j] += (unsigned short) 1<t != (short)(GameList[GameCnt].gmove & 0xFF)) if (best <= beta) killr3[ply] = mv; else if (mv != killr1[ply]) { killr2[ply] = killr1[ply]; killr1[ply] = mv; } killr0[ply] = ((best > 9000) ? mv : 0); } return (best); } 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 = side ^ 1; 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 || color[kf] != side || color[rf] != side || Mvboard[kf] != 0 || Mvboard[rf] != 0 || color[kt] != neutral || color[rt] != neutral || color[kt - 1] != neutral || SqAtakd3 (kf, xside) || SqAtakd3 (kt, xside) || SqAtakd3 (rt, xside)) return (false); } else { if (iop == 1) { Castled[side] = 1; castld[side] = true; Mvboard[kf]++; Mvboard[rf]++; } else { Castled[side] = 0; castld[side] = false; Mvboard[kf]--; Mvboard[rf]--; t0 = kt; kt = kf; kf = t0; t0 = rt; rt = rf; rf = t0; } board[kt] = king; color[rt] = color[kt] = side; Pindex[kt] = 0; board[kf] = no_piece; color[rf] = color[kf] = neutral; board[rt] = rook; Pindex[rt] = Pindex[rf]; board[rf] = no_piece; PieceList[side][Pindex[kt]] = kt; PieceList[side][Pindex[rt]] = rt; UpdateHashbd (side, king, kf, kt); UpdateHashbd (side, rook, rf, rt); } return (true); } void EnPassant (short int xside, short int f, short int t, short int iop) /* * Make or unmake an en passant move. */ { register short l; l = t + ((t > f) ? -8 : 8); if (iop == 1) { myEnPassant[xside] = 1; board[l] = no_piece; color[l] = neutral; } else { board[l] = pawn; color[l] = xside; myEnPassant[xside] = 0; } InitializeStats (); } 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, /* color of to square */ short int *tempc, /* piece at to square */ short int *tempsf, /* static value of piece on from */ short int *tempst, /* static value of piece on to */ short int *INCscore) /* score increment for pawn structure change */ /* * 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; register struct GameRec *g; xside = side ^ 1; g = &GameList[++GameCnt]; g->hashkey = hashkey; g->hashbd = hashbd; g->epssq = epsquare; f = node->f; t = node->t; epsquare = -1; /* FROMsquare = f;*/ TOsquare = t; *INCscore = 0; g->Game50 = Game50; g->gmove = (f << 8) | t; g->flags = node->flags; if (node->flags & cstlmask) { g->piece = no_piece; g->color = side; (void) castle (side, f, t, 1); Game50 = GameCnt; } else { if (!(node->flags & capture) && (board[f] != pawn)) {rpthash[side][hashkey & 0xFF]++;ISZERO++;} else Game50 = GameCnt; *tempsf = svalue[f]; *tempst = svalue[t]; g->piece = *tempb = board[t]; g->color = *tempc = color[t]; if (*tempc != neutral) { UpdatePieceList (*tempc, t, 1); /* if capture decrement pawn count */ if (*tempb == pawn) { --PawnCnt[*tempc][column (t)]; } if (board[f] == pawn) { cf = column (f); ct = column (t); /* move count from from to to */ --PawnCnt[side][cf]; ++PawnCnt[side][ct]; /* * calculate increment for pawn structure * changes */ /* doubled or more - */ if (PawnCnt[side][ct] > (1 + PawnCnt[side][cf])) *INCscore -= 15; /* went to empty column + */ else if (PawnCnt[side][ct] < 1 + PawnCnt[side][cf]) *INCscore += 15; /* * went to outside col or empty col on one * side ???????? */ else if (ct == 0 || ct == 7 || PawnCnt[side][ct + ct - cf] == 0) *INCscore -= 15; } mtl[xside] -= value[*tempb]; if (*tempb == pawn) pmtl[xside] -= valueP; UpdateHashbd (xside, *tempb, -1, t); *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; UpdateHashbd (side, pawn, f, -1); UpdateHashbd (side, board[t], f, -1); *INCscore -= *tempsf; } if (node->flags & epmask) EnPassant (xside, f, t, 1); else UpdateHashbd (side, board[t], f, t); 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 = side ^ 1; f = node->f; t = node->t; Game50 = GameList[GameCnt].Game50; 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; UpdateHashbd (side, (short) node->flags & pmask, -1, t); UpdateHashbd (side, pawn, -1, t); } 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; UpdateHashbd (xside, *tempb, -1, t); Mvboard[t]--; } if (node->flags & epmask) { EnPassant (xside, f, t, 2); } else UpdateHashbd (side, board[f], f, t); Mvboard[f]--; if (!(node->flags & capture) && (board[f] != pawn)) {rpthash[side][hashkey & 0xFF]--;ISZERO--;} } epsquare = GameList[GameCnt--].epssq; } 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; hashbd = hashkey = 0; 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)]; } Pindex[sq] = ((board[sq] == king) ? 0 : ++PieceCnt[color[sq]]); PieceList[color[sq]][Pindex[sq]] = sq; hashbd ^= hashcode[color[sq]][board[sq]][sq].bd; hashkey ^= hashcode[color[sq]][board[sq]][sq].key; } }