void Checkers::play() {
currentPlayer = 1;
std::vector<int> MoveStart;
std::vector<int> MoveEnd;
std::vector<int> AIMove;
currentState.Display();
while (terminalStatus != true) {
//currentState.Display();
switch (currentPlayer) {
case 1:
MoveStart = player1.getmoveStart();
MoveEnd = player1.getmoveEnd(MoveStart);
while (!LegalMove(MoveStart, MoveEnd, currentState) && getPiece(MoveStart) == 1 && !checkEmpty(MoveEnd)) {
MoveStart = player1.getmoveStart();
//swap values to match how table is laid out
std::swap(MoveStart[0], MoveStart[1]);
MoveEnd = player1.getmoveEnd(MoveStart);
std::swap(MoveEnd[0], MoveEnd[1]);
}
currentState.FullMove(MoveStart, MoveEnd);
//std::cout << MoveStart[0] << " " << MoveStart[1] << " to " << MoveEnd[0] << " " << MoveEnd[1] << std::endl;
currentPlayer = 2;
break;
case 2:
AIMove = player2.getmove(currentState);
//swap locations when moving, due to way Move is written to work with human inputs.
MoveStart = { AIMove[1],AIMove[0] };
MoveEnd = { AIMove[3],AIMove[2] };
currentState.FullMove(MoveStart, MoveEnd);
currentPlayer = 1;
break;
}
//std::cout << MoveStart[0] << " " << MoveStart[1] << " to " << MoveEnd[0] << " " << MoveEnd[1] << std::endl;
//currentState.FullMove(MoveStart, MoveEnd);
}
}
// 不吃子着法生成器
int PositionStruct::GenNonCapMoves(MoveStruct *lpmvs) const {
int i, sqSrc, sqDst, x, y, nSideTag;
SlideMoveStruct *lpsmv;
uint8_t *lpucsqDst, *lpucsqPin;
MoveStruct *lpmvsCurr;
// 生成不吃子着法的过程包括以下几个步骤：
lpmvsCurr = lpmvs;
nSideTag = SIDE_TAG(sdPlayer);
// 1. 生成帅(将)的着法
sqSrc = ucsqPieces[nSideTag + KING_FROM];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqKingMoves[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
// 找到一个着法后，首先判断是否吃到棋子
if (ucpcSquares[sqDst] == 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
}
// 2. 生成仕(士)的着法
for (i = ADVISOR_FROM; i <= ADVISOR_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqAdvisorMoves[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[sqDst] == 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
}
}
// 3. 生成相(象)的着法
for (i = BISHOP_FROM; i <= BISHOP_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqBishopMoves[sqSrc];
lpucsqPin = PreGen.ucsqBishopPins[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[*lpucsqPin] == 0 && ucpcSquares[sqDst] == 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
lpucsqPin ++;
}
}
}
// 4. 生成马的着法
for (i = KNIGHT_FROM; i <= KNIGHT_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqKnightMoves[sqSrc];
lpucsqPin = PreGen.ucsqKnightPins[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[*lpucsqPin] == 0 && ucpcSquares[sqDst] == 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
lpucsqPin ++;
}
}
}
// 5. 生成车和炮的着法，没有必要判断是否吃到本方棋子
for (i = ROOK_FROM; i <= CANNON_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
x = FILE_X(sqSrc);
y = RANK_Y(sqSrc);
lpsmv = RankMovePtr(x, y);
sqDst = lpsmv->ucNonCap[0] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
while (sqDst != sqSrc) {
__ASSERT(ucpcSquares[sqDst] == 0);
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
sqDst --;
}
sqDst = lpsmv->ucNonCap[1] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
while (sqDst != sqSrc) {
__ASSERT(ucpcSquares[sqDst] == 0);
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
sqDst ++;
}
lpsmv = FileMovePtr(x, y);
sqDst = lpsmv->ucNonCap[0] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
while (sqDst != sqSrc) {
__ASSERT(ucpcSquares[sqDst] == 0);
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
sqDst -= 16;
}
sqDst = lpsmv->ucNonCap[1] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
while (sqDst != sqSrc) {
__ASSERT(ucpcSquares[sqDst] == 0);
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
sqDst += 16;
}
}
}
// 6. 生成兵(卒)的着法
for (i = PAWN_FROM; i <= PAWN_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqPawnMoves[sdPlayer][sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[sqDst] == 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->dwmv = MOVE(sqSrc, sqDst);
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
}
}
return lpmvsCurr - lpmvs;
}
// 吃子着法生成器，按MVV(LVA)设定分值
int PositionStruct::GenCapMoves(MoveStruct *lpmvs) const {
int i, sqSrc, sqDst, pcCaptured;
int x, y, nSideTag, nOppSideTag;
bool bCanPromote;
SlideMoveStruct *lpsmv;
uint8_t *lpucsqDst, *lpucsqPin;
MoveStruct *lpmvsCurr;
// 生成吃子着法的过程包括以下几个步骤：
lpmvsCurr = lpmvs;
nSideTag = SIDE_TAG(sdPlayer);
nOppSideTag = OPP_SIDE_TAG(sdPlayer);
bCanPromote = PreEval.bPromotion && CanPromote();
// 1. 生成帅(将)的着法
sqSrc = ucsqPieces[nSideTag + KING_FROM];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqKingMoves[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
// 找到一个着法后，首先判断吃到的棋子是否是对方棋子，技巧是利用"nOppSideTag"的标志(16和32颠倒)，
// 如果是对方棋子，则保存MVV(LVA)值，即如果被吃子无保护，则只记MVV，否则记MVV-LVA(如果MVV>LVA的话)。
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 5); // 帅(将)的价值是5
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
}
// 2. 生成仕(士)的着法
for (i = ADVISOR_FROM; i <= ADVISOR_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqAdvisorMoves[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 1); // 仕(士)的价值是1
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
if (bCanPromote && CAN_PROMOTE(sqSrc)) {
lpmvsCurr->wmv = MOVE(sqSrc, sqSrc);
lpmvsCurr->wvl = 0;
lpmvsCurr ++;
}
}
}
// 3. 生成相(象)的着法
for (i = BISHOP_FROM; i <= BISHOP_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqBishopMoves[sqSrc];
lpucsqPin = PreGen.ucsqBishopPins[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[*lpucsqPin] == 0) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 1); // 相(象)的价值是1
lpmvsCurr ++;
}
}
lpucsqDst ++;
sqDst = *lpucsqDst;
lpucsqPin ++;
}
if (bCanPromote && CAN_PROMOTE(sqSrc)) {
lpmvsCurr->wmv = MOVE(sqSrc, sqSrc);
lpmvsCurr->wvl = 0;
lpmvsCurr ++;
}
}
}
// 4. 生成马的着法
for (i = KNIGHT_FROM; i <= KNIGHT_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqKnightMoves[sqSrc];
lpucsqPin = PreGen.ucsqKnightPins[sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
if (ucpcSquares[*lpucsqPin] == 0) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 3); // 马的价值是3
lpmvsCurr ++;
}
}
lpucsqDst ++;
sqDst = *lpucsqDst;
lpucsqPin ++;
}
}
}
// 5. 生成车的着法
for (i = ROOK_FROM; i <= ROOK_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
x = FILE_X(sqSrc);
y = RANK_Y(sqSrc);
lpsmv = RankMovePtr(x, y);
sqDst = lpsmv->ucRookCap[0] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 4); // 车的价值是4
lpmvsCurr ++;
}
}
sqDst = lpsmv->ucRookCap[1] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 4); // 车的价值是4
lpmvsCurr ++;
}
}
lpsmv = FileMovePtr(x, y);
sqDst = lpsmv->ucRookCap[0] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 4); // 车的价值是4
lpmvsCurr ++;
}
}
sqDst = lpsmv->ucRookCap[1] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 4); // 车的价值是4
lpmvsCurr ++;
}
}
}
}
// 6. 生成炮的着法
for (i = CANNON_FROM; i <= CANNON_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
x = FILE_X(sqSrc);
y = RANK_Y(sqSrc);
lpsmv = RankMovePtr(x, y);
sqDst = lpsmv->ucCannonCap[0] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 3); // 炮的价值是3
lpmvsCurr ++;
}
}
sqDst = lpsmv->ucCannonCap[1] + RANK_DISP(y);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 3); // 炮的价值是3
lpmvsCurr ++;
}
}
lpsmv = FileMovePtr(x, y);
sqDst = lpsmv->ucCannonCap[0] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 3); // 炮的价值是3
lpmvsCurr ++;
}
}
sqDst = lpsmv->ucCannonCap[1] + FILE_DISP(x);
__ASSERT_SQUARE(sqDst);
if (sqDst != sqSrc) {
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 3); // 炮的价值是3
lpmvsCurr ++;
}
}
}
}
// 7. 生成兵(卒)的着法
for (i = PAWN_FROM; i <= PAWN_TO; i ++) {
sqSrc = ucsqPieces[nSideTag + i];
if (sqSrc != 0) {
__ASSERT_SQUARE(sqSrc);
lpucsqDst = PreGen.ucsqPawnMoves[sdPlayer][sqSrc];
sqDst = *lpucsqDst;
while (sqDst != 0) {
__ASSERT_SQUARE(sqDst);
pcCaptured = ucpcSquares[sqDst];
if ((pcCaptured & nOppSideTag) != 0) {
__ASSERT(LegalMove(MOVE(sqSrc, sqDst)));
lpmvsCurr->wmv = MOVE(sqSrc, sqDst);
lpmvsCurr->wvl = MvvLva(sqDst, pcCaptured, 2); // 兵(卒)的价值是2
lpmvsCurr ++;
}
lpucsqDst ++;
sqDst = *lpucsqDst;
}
}
}
return lpmvsCurr - lpmvs;
}
static int negascout(struct SearchData *sd,
int alpha,
int beta,
const int depth,
int node_type
#if MP
,int exclusiveP
#endif /* MP */
) {
struct Position *p = sd->position;
struct SearchStatus *st;
int best = -INF;
int bestm = M_NONE;
int tmp;
int talpha;
int incheck;
int lmove;
int move;
int extend = 0;
int threat = FALSE;
int reduce_extensions;
int next_type;
int was_futile = FALSE;
#if FUTILITY
int is_futile;
int optimistic = 0;
#endif
#if MP
int deferred_cnt = 0;
int deferred_list[MAX_DEFERRED];
int deferred_depth[MAX_DEFERRED];
#endif
EnterNode(sd);
Nodes++;
/* check for search termination */
if (sd->master && TerminateSearch(sd)) {
AbortSearch = TRUE;
goto EXIT;
}
/* max search depth reached */
if (sd->ply >= MaxDepth) goto EXIT;
/*
* Check for insufficent material or theoretical draw.
*/
if ( /* InsufMat(p) || CheckDraw(p) || */ Repeated(p, FALSE)) {
best = 0;
goto EXIT;
}
/*
* check extension
*/
incheck = InCheck(p, p->turn);
if (incheck && p->material[p->turn] > 0) {
extend += CheckExtend(p);
ChkExt++;
}
/*
* Check the hashtable
*/
st = sd->current;
HTry++;
#if MP
switch (ProbeHT(p->hkey, &tmp, depth, &(st->st_hashmove), &threat, sd->ply,
exclusiveP, sd->localHashTable))
#else
switch (ProbeHT(p->hkey, &tmp, depth, &(st->st_hashmove), &threat, sd->ply))
#endif /* MP */
{
case ExactScore:
HHit++;
best = tmp;
goto EXIT;
case UpperBound:
if (tmp <= alpha) {
HHit++;
best = tmp;
goto EXIT;
}
break;
case LowerBound:
if (tmp >= beta) {
HHit++;
best = tmp;
goto EXIT;
}
break;
case Useless:
threat = !incheck && MateThreat(p, OPP(p->turn));
break;
#if MP
case OnEvaluation:
best = -ON_EVALUATION;
goto EXIT;
#endif
}
/*
* Probe EGTB
*/
if (depth > EGTBDepth && ProbeEGTB(p, &tmp, sd->ply)) {
best = tmp;
goto EXIT;
}
/*
* Probe recognizers
*/
switch (ProbeRecognizer(p, &tmp)) {
case ExactScore:
best = tmp;
goto EXIT;
case LowerBound:
if (tmp >= beta) {
best = tmp;
goto EXIT;
}
break;
case UpperBound:
if (tmp <= alpha) {
best = tmp;
goto EXIT;
}
break;
}
#if NULLMOVE
/*
* Null move search.
* See Christian Donninger, "Null Move and Deep Search"
* ICCA Journal Volume 16, No. 3, pp. 137-143
*/
if (!incheck && node_type == CutNode && !threat) {
int next_depth;
int nms;
next_depth = depth - ReduceNullMove;
if (next_depth > 0) {
next_depth = depth - ReduceNullMoveDeep;
}
DoNull(p);
if (next_depth < 0) {
nms = -quies(sd, -beta, -beta+1, 0);
} else {
#if MP
nms = -negascout(sd, -beta, -beta+1, next_depth, AllNode, 0);
#else
nms = -negascout(sd, -beta, -beta+1, next_depth, AllNode);
#endif
}
UndoNull(p);
if (AbortSearch) goto EXIT;
if (nms >= beta) {
if (p->nonPawn[p->turn] >= Value[Queen]) {
best = nms;
goto EXIT;
} else {
if (next_depth < 0) {
nms = quies(sd, beta-1, beta, 0);
} else {
#if MP
nms = negascout(sd, beta-1, beta, next_depth, CutNodeNoNull,
0);
#else
nms = negascout(sd, beta-1, beta, next_depth,
CutNodeNoNull);
#endif
}
if (nms >= beta) {
best = nms;
goto EXIT;
} else {
extend += ExtendZugzwang;
ZZExt++;
}
}
} else if (nms <= -CMLIMIT) {
threat = TRUE;
}
}
#endif /* NULLMOVE */
lmove = (p->actLog-1)->gl_Move;
reduce_extensions = (sd->ply > 2*sd->depth);
talpha = alpha;
switch (node_type) {
case AllNode:
next_type = CutNode;
break;
case CutNode:
case CutNodeNoNull:
next_type = AllNode;
break;
default:
next_type = PVNode;
break;
}
#if FUTILITY
is_futile = !incheck && !threat && alpha < CMLIMIT && alpha > -CMLIMIT;
if (is_futile) {
if (p->turn == White) {
optimistic = MaterialBalance(p) + MaxPos;
} else {
optimistic = -MaterialBalance(p) + MaxPos;
}
}
#endif /* FUTILITY */
/*
* Internal iterative deepening. If we do not have a move, we try
* a shallow search to find a good candidate.
*/
if (depth > 2*OnePly && ((alpha + 1) != beta) && !LegalMove(p, st->st_hashmove)) {
int useless;
#if MP
useless = negascout(sd, alpha, beta, depth-2*OnePly, PVNode, 0);
#else
useless = negascout(sd, alpha, beta, depth-2*OnePly, PVNode);
#endif
st->st_hashmove = sd->pv_save[sd->ply+1];
}
/*
* Search all legal moves
*/
while ((move = incheck ? NextEvasion(sd) : NextMove(sd)) != M_NONE) {
int next_depth = extend;
if (move & M_CANY && !MayCastle(p, move)) continue;
/*
* recapture extension
*/
if ((move & M_CAPTURE) && (lmove & M_CAPTURE) &&
M_TO(move) == M_TO(lmove) &&
IsRecapture(p->piece[M_TO(move)], (p->actLog-1)->gl_Piece)) {
RCExt += 1;
next_depth += ExtendRecapture[TYPE(p->piece[M_TO(move)])];
}
/*
* passed pawn push extension
*/
if (TYPE(p->piece[M_FROM(move)]) == Pawn &&
p->nonPawn[OPP(p->turn)] <= Value[Queen]) {
int to = M_TO(move);
if (((p->turn == White && to >= a7)
|| (p->turn == Black && to <= h2))
&& IsPassed(p, to, p->turn) && SwapOff(p, move) >= 0) {
next_depth += ExtendPassedPawn;
PPExt += 1;
}
}
/*
* limit extensions to sensible range.
*/
if (reduce_extensions) next_depth /= 2;
next_depth += depth - OnePly;
#if FUTILITY
/*
* Futility cutoffs
*/
if (is_futile) {
if (next_depth < 0 && !IsCheckingMove(p, move)) {
tmp = optimistic + ScoreMove(p, move);
if (tmp <= alpha) {
if (tmp > best) {
best = tmp;
bestm = move;
was_futile = TRUE;
}
continue;
}
}
#if EXTENDED_FUTILITY
/*
* Extended futility cutoffs and limited razoring.
* See Ernst A. Heinz, "Extended Futility Pruning"
* ICCA Journal Volume 21, No. 2, pp 75-83
*/
else if (next_depth >= 0 && next_depth < OnePly
&& !IsCheckingMove(p, move)) {
tmp = optimistic + ScoreMove(p, move) + (3*Value[Pawn]);
if (tmp <= alpha) {
if (tmp > best) {
best = tmp;
bestm = move;
was_futile = TRUE;
}
continue;
}
}
#if RAZORING
else if (next_depth >= OnePly && next_depth < 2*OnePly
&& !IsCheckingMove(p, move)) {
tmp = optimistic + ScoreMove(p, move) + (6*Value[Pawn]);
if (tmp <= alpha) {
next_depth -= OnePly;
}
}
#endif /* RAZORING */
#endif /* EXTENDED_FUTILITY */
}
#endif /* FUTILITY */
DoMove(p, move);
if (InCheck(p, OPP(p->turn))) {
UndoMove(p, move);
} else {
/*
* Check extension
*/
if (p->material[p->turn] > 0 && InCheck(p, p->turn)) {
next_depth += (reduce_extensions) ?
ExtendInCheck>>1 : ExtendInCheck;
}
/*
* Recursively search this position. If depth is exhausted, use
* quies, otherwise use negascout.
*/
if (next_depth < 0) {
tmp = -quies(sd, -beta, -talpha, 0);
} else if (bestm != M_NONE && !was_futile) {
#if MP
tmp = -negascout(sd, -talpha-1, -talpha, next_depth, next_type,
bestm != M_NONE);
if (tmp != ON_EVALUATION && tmp > talpha && tmp < beta) {
tmp = -negascout(sd, -beta, -tmp, next_depth,
node_type == PVNode ? PVNode : AllNode,
bestm != M_NONE);
}
#else
tmp = -negascout(sd, -talpha-1, -talpha, next_depth, next_type);
if (tmp > talpha && tmp < beta) {
tmp = -negascout(sd, -beta, -tmp, next_depth,
node_type == PVNode ? PVNode : AllNode);
}
#endif /* MP */
} else {
#if MP
tmp = -negascout(sd, -beta, -talpha, next_depth, next_type,
bestm != M_NONE);
#else
tmp = -negascout(sd, -beta, -talpha, next_depth, next_type);
#endif /* MP */
}
UndoMove(p, move);
if (AbortSearch) goto EXIT;
#if MP
if (tmp == ON_EVALUATION) {
/*
* This child is ON_EVALUATION. Remember move and
* depth.
*/
deferred_list[deferred_cnt] = move;
deferred_depth[deferred_cnt] = next_depth;
deferred_cnt++;
} else {
#endif /* MP */
/*
* beta cutoff, enter move in Killer/Countermove table
*/
if (tmp >= beta) {
if (!(move & M_TACTICAL)) {
PutKiller(sd, move);
sd->counterTab[p->turn][lmove & 4095] = move;
}
StoreResult(sd, tmp, alpha, beta, move, depth, threat);
best = tmp;
goto EXIT;
}
/*
* Improvement on best move to date
*/
if (tmp > best) {
best = tmp;
bestm = move;
was_futile = FALSE;
if (best > talpha) {
talpha = best;
}
}
next_type = CutNode;
#if MP
}
#endif /* MP */
}
}
