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Hall of Fame Game Cube 2: Parlor
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gnuchess
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search.c
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1995-02-22
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/*
C source for GNU CHESS
Revision: 1990-12-26
Modified by Daryl Baker for use in MS WINDOWS environment
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.
*/
#define NOATOM
#define NOCLIPBOARD
#define NOCREATESTRUCT
#define NOFONT
#define NOREGION
#define NOSOUND
#define NOWH
#define NOWINOFFSETS
#define NOCOMM
#define NOKANJI
#include <windows.h>
#include <windowsx.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <malloc.h>
#include <stdio.h>
#include "gnuchess.h"
#include "defs.h"
#ifdef WIN32
#define _BASEETC
#else
#define _BASEETC _based(_segname("_CODE"))
#endif
#if ttblsz
extern unsigned long hashkey, hashbd;
/*extern struct hashval hashcode[2][7][64];*/
/*extern struct hashentry huge ttable[2][ttblsz];*/
extern struct hashval far *hashcode;
extern struct hashentry far *ttable;
#endif /* ttblsz */
/*extern unsigned char history[8192];*/
extern unsigned char far * history;
extern short rpthash[2][256];
/*extern unsigned char nextpos[8][64][64];*/
/*extern unsigned char nextdir[8][64][64];*/
extern unsigned char far *nextpos;
extern unsigned char far *nextdir;
extern short FROMsquare, TOsquare, Zscore, zwndw;
extern unsigned short PV, Swag0, Swag1, Swag2, Swag3, Swag4;
extern unsigned short killr0[maxdepth], killr1[maxdepth];
extern unsigned short killr2[maxdepth], killr3[maxdepth];
extern short Pscore[maxdepth], Tscore[maxdepth];
extern unsigned long hashkey, hashbd;
extern short ChkFlag[maxdepth], CptrFlag[maxdepth], PawnThreat[maxdepth];
extern short mtl[2], pmtl[2], emtl[2], hung[2];
extern short player, xwndw, rehash;
extern short PieceCnt[2];
extern long NodeCnt, ETnodes, EvalNodes, HashCnt, FHashCnt, HashCol;
extern short HasKnight[2], HasBishop[2], HasRook[2], HasQueen[2];
extern short Pindex[64];
static short _BASEETC rank7[3] = {6, 1, 0};
static short _BASEETC kingP[3] = {4, 60, 0};
static short _BASEETC value[7] =
{0, valueP, valueN, valueB, valueR, valueQ, valueK};
static short _BASEETC sweep[8] =
{false, false, false, true, true, true, false, false};
static short _BASEETC ptype[2][8] = {
no_piece, pawn, knight, bishop, rook, queen, king, no_piece,
no_piece, bpawn, knight, bishop, rook, queen, king, no_piece};
static short _BASEETC control[7] =
{0, ctlP, ctlN, ctlB, ctlR, ctlQ, ctlK};
/* ............ MOVE GENERATION & SEARCH ROUTINES .............. */
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 (HWND hWnd, 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; */
*(history+i) = 0;
#else
_fmemset ( history, 0, 8192 * sizeof (char));
#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 (hWnd, side, 1, Sdepth, alpha, beta, PrVar, &rpt);
for (i = 1; i <= Sdepth; i++)
killr0[i] = PrVar[i];
if (score < alpha)
{
ShowDepth ('\xbb' /*'-'*/);
ExtraTime = 10 * ResponseTime;
/* ZeroTTable (); */
score = search (hWnd, side, 1, Sdepth, -9000, score, PrVar, &rpt);
}
if (score > beta && !(root->flags & exact))
{
ShowDepth ('\xab' /*'+'*/);
ExtraTime = 0;
/* ZeroTTable (); */
score = search (hWnd, 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, '\xb7' /*'.'*/);
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 (hWnd);
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;
}
int
parse (FILE *fd, short unsigned 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);
}
inline void
repetition (short int *cnt)
/*
Check for draw by threefold repetition.
*/
{
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 (HWND hWnd,
short int side,
short int ply,
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.
*/
#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 far *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);
}
/* This test has been modified in 3.1 from 1.55 code. I think the mods
have introduced an error in the search which causes the programme
to run away from checking moves - hence the failure to find mates
and to play through mate situations.
The fixes introduced solve the problem reported by:
cambell@rnd.GBA.NYU.EDU
in the mate example.
J.Birmingham.
*/
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; /* this was depth=1 in original ?bug? */
else if (score <= beta && MateThreat)
++depth; /* this was also set to depth=1 ?bug? */
}
/* end of changed section J.Birmingham. */
#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++)
{
/* Little code segment to allow cooperative multitasking */
{
MSG msg;
extern HANDLE hAccel;
if ( !flag.timeout && PeekMessage(&msg, (HWND)NULL, (UINT)NULL,
(UINT)NULL, PM_REMOVE)){
if ( !TranslateAccelerator (hWnd, hAccel, &msg) ) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
/* End of segment */
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 (hWnd, 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, '\xab' /*'+'*/);
else if (best < alpha)
ShowResults (best, bstline, '\xbb' /* '-'*/);
else
ShowResults (best, bstline, '\xb1' /*'&'*/);
}
}
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 (*(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)*7*64+(piece)*64+f)->bd;\
hashkey ^= (hashcode+(side)*7*64+(piece)*64+f)->key;\
}\
if ((t) >= 0)\
{\
hashbd ^= (hashcode+(side)*7*64+(piece)*64+t)->bd;\
hashkey ^= (hashcode+(side)*7*64+(piece)*64+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.
*/
{
struct hashentry far *ptbl;
register unsigned short i;
/* ptbl = &ttable[side][hashkey & (ttblsz - 1)]; */
ptbl = ttable+side*2+(hashkey & (ttblsz - 1));
/* rehash max rehash times */
for (i = 1; ptbl->hashbd != hashbd && i <= rehash; i++)
/* ptbl = &ttable[side][(hashkey + i) & (ttblsz - 1)]; */
ptbl = ttable+side*2+((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,
short unsigned int mv)
/*
Store the current board position in the transposition table.
*/
{
struct hashentry far *ptbl;
register unsigned short i;
/* ptbl = &ttable[side][hashkey & (ttblsz - 1)]; */
ptbl = ttable+side*2+(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)]; */
ptbl = ttable+side*2+((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; */
(ttable+side*2+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;
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;
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;
unsigned short mv;
struct leaf far *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]; */
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;
unsigned char far *ppos, far *pdir;
piece = board[sq];
ppos = nextpos+ptype[side][piece]*64*64+sq*64;
pdir = nextdir+ptype[side][piece]*64*64+sq*64;
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.
*/
{
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.
*/
{
short u, sq, xside;
struct leaf far *node;
unsigned char far *ppos, far *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*64*64+sq*64;
pdir = nextdir+piece*64*64+sq*64;
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]*64*64+sq*64;
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]*64*64+sq*64;
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. */
{
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 far * 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.
*/
{
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 far * node,
short int *tempb,
short int *tempc,
short int *tempsf,
short int *tempst)
/*
Take back a move.
*/
{
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.
*/
{
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]*7*64+board[sq]*64+sq)->bd;
hashkey ^= (hashcode+color[sq]*7*64+board[sq]*64+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;
unsigned char far *ppos, far *pdir;
short xside;
xside = otherside[side];
pdir = nextdir+ptype[xside][pawn]*64*64+sq*64;
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*64*64+sq*64;
pdir = nextdir+bishop*64*64+sq*64;
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*64*64+sq*64;
pdir = nextdir+rook*64*64+sq*64;
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*64*64+sq*64;
u = pdir[sq];
do
{
if (color[u] == side && board[u] == knight)
return (true);
u = pdir[u];
} while (u != sq);
return (false);
}
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.
*/
{
short u, c, sq;
unsigned char far *ppos, far *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*64*64+sq*64;
pdir = nextdir+piece*64*64+sq*64;
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]*64*64+sq*64;
u = pdir[sq]; /* follow captures thread for pawns */
do
{
a[u] = ++a[u] | c;
u = pdir[u];
} while (u != sq);
}
}
}