/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish 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 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+
+ Stockfish 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
+#include <algorithm>
#include <cassert>
-#include "history.h"
#include "movegen.h"
#include "movepick.h"
#include "search.h"
-#include "value.h"
-
-
-////
-//// Local definitions
-////
+#include "types.h"
namespace {
- /// Variables
-
- int MainSearchPhaseIndex;
- int EvasionsPhaseIndex;
- int QsearchWithChecksPhaseIndex;
- int QsearchWithoutChecksPhaseIndex;
-
+ enum Sequencer {
+ MAIN_SEARCH, TT_MOVE_S1, GOOD_CAPTURES_S1, KILLERS_S1, NONCAPTURES_1_S1,
+ NONCAPTURES_2_S1, BAD_CAPTURES_S1, STOP_S1,
+ EVASIONS, TT_MOVE_S2, EVASIONS_S2, STOP_S2,
+ CAPTURES_AND_CHECKS, TT_MOVE_S3, QCAPTURES_S3, QCHECKS_S3, STOP_S3,
+ CAPTURES, TT_MOVE_S4, QCAPTURES_S4, STOP_S4,
+ RECAPTURES, TT_MOVE_S5, RECAPTURES_S5, STOP_S5,
+ PROBCUT, TT_MOVE_S6, GOOD_CAPTURES_S6, STOP_S6
+ };
+
+ // Unary predicate used by std::partition to split positive scores from remaining
+ // ones so to sort separately the two sets, and with the second sort delayed.
+ inline bool has_positive_score(const MoveStack& move) { return move.score > 0; }
+
+ // Picks and pushes to the front the best move in range [firstMove, lastMove),
+ // it is faster than sorting all the moves in advance when moves are few, as
+ // normally are the possible captures.
+ inline MoveStack* pick_best(MoveStack* firstMove, MoveStack* lastMove)
+ {
+ std::swap(*firstMove, *std::max_element(firstMove, lastMove));
+ return firstMove;
+ }
}
-// Static array definition
-MovePicker::MovegenPhase MovePicker::PhaseTable[32];
-
-
-////
-//// Functions
-////
-
-
-/// Constructor for the MovePicker class. Apart from the position for which
-/// it is asked to pick legal moves, MovePicker also wants some information
+/// Constructors for the MovePicker class. As arguments we pass information
/// to help it to return the presumably good moves first, to decide which
/// moves to return (in the quiescence search, for instance, we only want to
/// search captures, promotions and some checks) and about how important good
/// move ordering is at the current node.
-MovePicker::MovePicker(Position &p, bool pvnode, Move ttm, Move mk,
- Move k1, Move k2, Depth dpth) {
- pos = &p;
- pvNode = pvnode;
- ttMove = ttm;
- mateKiller = (mk == ttm)? MOVE_NONE : mk;
- killer1 = k1;
- killer2 = k2;
- depth = dpth;
- movesPicked = 0;
- numOfMoves = 0;
- numOfBadCaptures = 0;
- dc = p.discovered_check_candidates(p.side_to_move());
-
- if(p.is_check())
- phaseIndex = EvasionsPhaseIndex;
- else if(depth > Depth(0))
- phaseIndex = MainSearchPhaseIndex;
- else if(depth == Depth(0))
- phaseIndex = QsearchWithChecksPhaseIndex;
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
+ Search::Stack* ss, Value beta) : pos(p), H(h), depth(d) {
+ captureThreshold = 0;
+ badCaptures = moves + MAX_MOVES;
+
+ assert(d > DEPTH_ZERO);
+
+ if (p.in_check())
+ {
+ killers[0].move = killers[1].move = MOVE_NONE;
+ phase = EVASIONS;
+ }
else
- phaseIndex = QsearchWithoutChecksPhaseIndex;
+ {
+ killers[0].move = ss->killers[0];
+ killers[1].move = ss->killers[1];
+
+ // Consider sligtly negative captures as good if at low depth and far from beta
+ if (ss && ss->eval < beta - PawnValueMidgame && d < 3 * ONE_PLY)
+ captureThreshold = -PawnValueMidgame;
+
+ // Consider negative captures as good if still enough to reach beta
+ else if (ss && ss->eval > beta)
+ captureThreshold = beta - ss->eval;
- pinned = p.pinned_pieces(p.side_to_move());
+ phase = MAIN_SEARCH;
+ }
- finished = false;
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+ phase += int(ttMove == MOVE_NONE);
+ go_next_phase();
}
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, Square recaptureSq)
+ : pos(p), H(h) {
-/// MovePicker::get_next_move() is the most important method of the MovePicker
-/// class. It returns a new legal move every time it is called, until there
-/// are no more moves left of the types we are interested in.
+ assert(d <= DEPTH_ZERO);
-Move MovePicker::get_next_move() {
- Move move;
+ if (p.in_check())
+ phase = EVASIONS;
- while(true) {
- // If we already have a list of generated moves, pick the best move from
- // the list, and return it:
- move = this->pick_move_from_list();
- if(move != MOVE_NONE) {
- assert(move_is_ok(move));
- return move;
- }
-
- // Next phase:
- phaseIndex++;
- switch(PhaseTable[phaseIndex]) {
-
- case PH_TT_MOVE:
- if(ttMove != MOVE_NONE) {
- assert(move_is_ok(ttMove));
- Move m = generate_move_if_legal(*pos, ttMove, pinned);
- if(m != MOVE_NONE) {
- assert(m == ttMove);
- return m;
- }
- }
- break;
-
- case PH_MATE_KILLER:
- if(mateKiller != MOVE_NONE) {
- assert(move_is_ok(mateKiller));
- Move m = generate_move_if_legal(*pos, mateKiller, pinned);
- if(m != MOVE_NONE) {
- assert(m == mateKiller);
- return m;
- }
- }
- break;
-
- case PH_GOOD_CAPTURES:
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_captures(*pos, moves);
- this->score_captures();
- movesPicked = 0;
- break;
-
- case PH_BAD_CAPTURES:
- badCapturesPicked = 0;
- break;
-
- case PH_NONCAPTURES:
- numOfMoves = generate_noncaptures(*pos, moves);
- this->score_noncaptures();
- movesPicked = 0;
- break;
-
- case PH_EVASIONS:
- assert(pos->is_check());
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_evasions(*pos, moves);
- this->score_evasions();
- movesPicked = 0;
- break;
-
- case PH_QCAPTURES:
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_captures(*pos, moves);
- this->score_qcaptures();
- movesPicked = 0;
- break;
-
- case PH_QCHECKS:
- numOfMoves = generate_checks(*pos, moves, dc);
- movesPicked = 0;
- break;
-
- case PH_STOP:
- return MOVE_NONE;
-
- default:
- assert(false);
- return MOVE_NONE;
- }
- }
+ else if (d >= DEPTH_QS_CHECKS)
+ phase = CAPTURES_AND_CHECKS;
- assert(false);
+ else if (d >= DEPTH_QS_RECAPTURES)
+ {
+ phase = CAPTURES;
- return MOVE_NONE;
+ // Skip TT move if is not a capture or a promotion, this avoids
+ // qsearch tree explosion due to a possible perpetual check or
+ // similar rare cases when TT table is full.
+ if (ttm != MOVE_NONE && !pos.is_capture_or_promotion(ttm))
+ ttm = MOVE_NONE;
+ }
+ else
+ {
+ phase = RECAPTURES;
+ recaptureSquare = recaptureSq;
+ ttm = MOVE_NONE;
+ }
+
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+ phase += int(ttMove == MOVE_NONE);
+ go_next_phase();
}
+MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType parentCapture)
+ : pos(p), H(h) {
+
+ assert (!pos.in_check());
-/// A variant of get_next_move() which takes a lock as a parameter, used to
-/// prevent multiple threads from picking the same move at a split point.
+ // In ProbCut we consider only captures better than parent's move
+ captureThreshold = PieceValueMidgame[Piece(parentCapture)];
+ phase = PROBCUT;
-Move MovePicker::get_next_move(Lock &lock) {
- Move m;
+ if ( ttm != MOVE_NONE
+ && (!pos.is_capture(ttm) || pos.see(ttm) <= captureThreshold))
+ ttm = MOVE_NONE;
- lock_grab(&lock);
- if(finished) {
- lock_release(&lock);
- return MOVE_NONE;
- }
- m = this->get_next_move();
- if(m == MOVE_NONE)
- finished = true;
- lock_release(&lock);
-
- return m;
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+ phase += int(ttMove == MOVE_NONE);
+ go_next_phase();
}
-
-/// MovePicker::number_of_moves() simply returns the numOfMoves member
-/// variable. It is intended to be used in positions where the side to move
-/// is in check, for detecting checkmates or situations where there is only
-/// a single reply to check.
-int MovePicker::number_of_moves() const {
- return numOfMoves;
+/// MovePicker::go_next_phase() generates, scores and sorts the next bunch
+/// of moves when there are no more moves to try for the current phase.
+
+void MovePicker::go_next_phase() {
+
+ curMove = moves;
+
+ switch (++phase) {
+
+ case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3:
+ case TT_MOVE_S4: case TT_MOVE_S5: case TT_MOVE_S6:
+ lastMove = curMove + 1;
+ return;
+
+ case GOOD_CAPTURES_S1:
+ case GOOD_CAPTURES_S6:
+ lastMove = generate<MV_CAPTURE>(pos, moves);
+ score_captures();
+ return;
+
+ case KILLERS_S1:
+ curMove = killers;
+ lastMove = curMove + 2;
+ return;
+
+ case NONCAPTURES_1_S1:
+ lastNonCapture = lastMove = generate<MV_NON_CAPTURE>(pos, moves);
+ score_noncaptures();
+ lastMove = std::partition(curMove, lastMove, has_positive_score);
+ sort<MoveStack>(curMove, lastMove);
+ return;
+
+ case NONCAPTURES_2_S1:
+ curMove = lastMove;
+ lastMove = lastNonCapture;
+ if (depth >= 3 * ONE_PLY)
+ sort<MoveStack>(curMove, lastMove);
+ return;
+
+ case BAD_CAPTURES_S1:
+ // Bad captures SEE value is already calculated so just pick
+ // them in order to get SEE move ordering.
+ curMove = badCaptures;
+ lastMove = moves + MAX_MOVES;
+ return;
+
+ case EVASIONS_S2:
+ assert(pos.in_check());
+ lastMove = generate<MV_EVASION>(pos, moves);
+ score_evasions();
+ return;
+
+ case QCAPTURES_S3:
+ case QCAPTURES_S4:
+ lastMove = generate<MV_CAPTURE>(pos, moves);
+ score_captures();
+ return;
+
+ case RECAPTURES_S5:
+ lastMove = generate<MV_CAPTURE>(pos, moves);
+ return;
+
+ case QCHECKS_S3:
+ lastMove = generate<MV_NON_CAPTURE_CHECK>(pos, moves);
+ return;
+
+ case STOP_S1: case STOP_S2: case STOP_S3:
+ case STOP_S4: case STOP_S5: case STOP_S6:
+ lastMove = curMove + 1; // Avoid another go_next_phase() call
+ return;
+
+ default:
+ assert(false);
+ }
}
-/// MovePicker::score_captures(), MovePicker::score_noncaptures(),
-/// MovePicker::score_evasions() and MovePicker::score_qcaptures() assign a
-/// numerical move ordering score to each move in a move list. The moves
-/// with highest scores will be picked first by
-/// MovePicker::pick_move_from_list().
+/// MovePicker::score_captures(), MovePicker::score_noncaptures() and
+/// MovePicker::score_evasions() assign a numerical move ordering score
+/// to each move in a move list. The moves with highest scores will be
+/// picked first by next_move().
void MovePicker::score_captures() {
// Winning and equal captures in the main search are ordered by MVV/LVA.
// Suprisingly, this appears to perform slightly better than SEE based
- // move ordering. The reason is probably that in a position with a winning
+ // move ordering. The reason is probably that in a position with a winning
// capture, capturing a more valuable (but sufficiently defended) piece
- // first usually doesn't hurt. The opponent will have to recapture, and
+ // first usually doesn't hurt. The opponent will have to recapture, and
// the hanging piece will still be hanging (except in the unusual cases
- // where it is possible to recapture with the hanging piece). Exchanging
+ // where it is possible to recapture with the hanging piece). Exchanging
// big pieces before capturing a hanging piece probably helps to reduce
// the subtree size.
- for(int i = 0; i < numOfMoves; i++) {
- int seeValue = pos->see(moves[i].move);
- if(seeValue >= 0) {
- if(move_promotion(moves[i].move))
- moves[i].score = QueenValueMidgame;
- else
- moves[i].score =
- int(pos->midgame_value_of_piece_on(move_to(moves[i].move))) -
- int(pos->type_of_piece_on(move_from(moves[i].move)));
- }
- else
- moves[i].score = seeValue;
-
+ // In main search we want to push captures with negative SEE values to
+ // badCaptures[] array, but instead of doing it now we delay till when
+ // the move has been picked up in pick_move_from_list(), this way we save
+ // some SEE calls in case we get a cutoff (idea from Pablo Vazquez).
+ Move m;
+
+ // Use MVV/LVA ordering
+ for (MoveStack* cur = moves; cur != lastMove; cur++)
+ {
+ m = cur->move;
+ cur->score = PieceValueMidgame[pos.piece_on(to_sq(m))]
+ - type_of(pos.piece_moved(m));
+
+ if (is_promotion(m))
+ cur->score += PieceValueMidgame[Piece(promotion_piece_type(m))];
}
}
void MovePicker::score_noncaptures() {
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(m == killer1)
- moves[i].score = HistoryMax + 2;
- else if(m == killer2)
- moves[i].score = HistoryMax + 1;
- else
- moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m);
- }
-}
-void MovePicker::score_evasions() {
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(m == ttMove)
- moves[i].score = 2*HistoryMax;
- else if(!pos->square_is_empty(move_to(m))) {
- int seeScore = pos->see(m);
- moves[i].score = (seeScore >= 0)? seeScore + HistoryMax : seeScore;
- }
- else
- moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m);
+ Move m;
+ Square from;
+
+ for (MoveStack* cur = moves; cur != lastMove; cur++)
+ {
+ m = cur->move;
+ from = from_sq(m);
+ cur->score = H.value(pos.piece_on(from), to_sq(m));
}
}
-void MovePicker::score_qcaptures() {
- // Use MVV/LVA ordering.
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(move_promotion(m))
- moves[i].score = QueenValueMidgame;
- else
- moves[i].score =
- int(pos->midgame_value_of_piece_on(move_to(m))) -
- int(pos->midgame_value_of_piece_on(move_to(m))) / 64;
+void MovePicker::score_evasions() {
+ // Try good captures ordered by MVV/LVA, then non-captures if
+ // destination square is not under attack, ordered by history
+ // value, and at the end bad-captures and non-captures with a
+ // negative SEE. This last group is ordered by the SEE score.
+ Move m;
+ int seeScore;
+
+ // Skip if we don't have at least two moves to order
+ if (lastMove < moves + 2)
+ return;
+
+ for (MoveStack* cur = moves; cur != lastMove; cur++)
+ {
+ m = cur->move;
+ if ((seeScore = pos.see_sign(m)) < 0)
+ cur->score = seeScore - History::MaxValue; // Be sure we are at the bottom
+ else if (pos.is_capture(m))
+ cur->score = PieceValueMidgame[pos.piece_on(to_sq(m))]
+ - type_of(pos.piece_moved(m)) + History::MaxValue;
+ else
+ cur->score = H.value(pos.piece_moved(m), to_sq(m));
}
}
+/// MovePicker::next_move() is the most important method of the MovePicker class.
+/// It returns a new pseudo legal move every time it is called, until there
+/// are no more moves left. It picks the move with the biggest score from a list
+/// of generated moves taking care not to return the tt move if has already been
+/// searched previously. Note that this function is not thread safe so should be
+/// lock protected by caller when accessed through a shared MovePicker object.
-/// MovePicker::pick_move_from_list() picks the move with the biggest score
-/// from a list of generated moves (moves[] or badCaptures[], depending on
-/// the current move generation phase). It takes care not to return the
-/// transposition table move if that has already been serched previously.
-/// While picking captures in the PH_GOOD_CAPTURES phase (i.e. while picking
-/// non-losing captures in the main search), it moves all captures with
-/// negative SEE values to the badCaptures[] array.
+Move MovePicker::next_move() {
-Move MovePicker::pick_move_from_list() {
- int bestScore = -10000000;
- int bestIndex;
Move move;
- switch(PhaseTable[phaseIndex]) {
-
- case PH_GOOD_CAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++) {
- if(moves[i].score < 0) {
- // Losing capture, move it to the badCaptures[] array
- assert(numOfBadCaptures < 63);
- badCaptures[numOfBadCaptures++] = moves[i];
- moves[i--] = moves[--numOfMoves];
- }
- else if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
- }
- }
- if(bestIndex != -1) { // Found a good capture
- move = moves[bestIndex].move;\r
- moves[bestIndex] = moves[movesPicked++];
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- }
- break;
-
- case PH_NONCAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
-
- // If this is a PV node or we have only picked a few moves, scan
- // the entire move list for the best move. If many moves have already
- // been searched and it is not a PV node, we are probably failing low
- // anyway, so we just pick the first move from the list.
- if(pvNode || movesPicked < 12) {
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
+ while (true)
+ {
+ while (curMove == lastMove)
+ go_next_phase();
+
+ switch (phase) {
+
+ case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3:
+ case TT_MOVE_S4: case TT_MOVE_S5: case TT_MOVE_S6:
+ curMove++;
+ return ttMove;
+ break;
+
+ case GOOD_CAPTURES_S1:
+ move = pick_best(curMove++, lastMove)->move;
+ if (move != ttMove)
+ {
+ assert(captureThreshold <= 0); // Otherwise we must use see instead of see_sign
+
+ // Check for a non negative SEE now
+ int seeValue = pos.see_sign(move);
+ if (seeValue >= captureThreshold)
+ return move;
+
+ // Losing capture, move it to the tail of the array
+ (--badCaptures)->move = move;
+ badCaptures->score = seeValue;
}
- }
- else
- bestIndex = movesPicked;
-
- if(bestIndex != -1) {
- move = moves[bestIndex].move;\r
- moves[bestIndex] = moves[movesPicked++];
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- }
- break;
-
- case PH_EVASIONS:
- assert(pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
- }
-
- if(bestIndex != -1) {
- move = moves[bestIndex].move;\r
- moves[bestIndex] = moves[movesPicked++];
- return move;
- }
- }
- break;
-
- case PH_BAD_CAPTURES:
- assert(!pos->is_check());
- assert(badCapturesPicked >= 0);
- // It's probably a good idea to use SEE move ordering here, instead
- // of just picking the first move. FIXME
- while(badCapturesPicked < numOfBadCaptures) {
- move = badCaptures[badCapturesPicked++].move;
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- break;
-
- case PH_QCAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- if(movesPicked < 4) {
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
- }
- }
- else
- bestIndex = movesPicked;
-
- if(bestIndex != -1) {
- move = moves[bestIndex].move;\r
- moves[bestIndex] = moves[movesPicked++];
- // Remember to change the line below if we decide to hash the qsearch!
- // Maybe also postpone the legality check until after futility pruning?
- if(/* move != ttMove && */ pos->move_is_legal(move, pinned))
+ break;
+
+ case GOOD_CAPTURES_S6:
+ move = pick_best(curMove++, lastMove)->move;
+ if ( move != ttMove
+ && pos.see(move) > captureThreshold)
+ return move;
+ break;
+
+ case KILLERS_S1:
+ move = (curMove++)->move;
+ if ( move != MOVE_NONE
+ && pos.is_pseudo_legal(move)
+ && move != ttMove
+ && !pos.is_capture(move))
+ return move;
+ break;
+
+ case NONCAPTURES_1_S1:
+ case NONCAPTURES_2_S1:
+ move = (curMove++)->move;
+ if ( move != ttMove
+ && move != killers[0].move
+ && move != killers[1].move)
+ return move;
+ break;
+
+ case BAD_CAPTURES_S1:
+ move = pick_best(curMove++, lastMove)->move;
return move;
- }
- }
- break;
-
- case PH_QCHECKS:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- // Perhaps we should do something better than just picking the first
- // move here? FIXME
- while(movesPicked < numOfMoves) {
- move = moves[movesPicked++].move;
- // Remember to change the line below if we decide to hash the qsearch!
- if(/* move != ttMove && */ pos->move_is_legal(move, pinned))
- return move;
- }
- break;
- default:
- break;
+ case EVASIONS_S2:
+ case QCAPTURES_S3:
+ case QCAPTURES_S4:
+ move = pick_best(curMove++, lastMove)->move;
+ if (move != ttMove)
+ return move;
+ break;
+
+ case RECAPTURES_S5:
+ move = (curMove++)->move;
+ if (to_sq(move) == recaptureSquare)
+ return move;
+ break;
+
+ case QCHECKS_S3:
+ move = (curMove++)->move;
+ if (move != ttMove)
+ return move;
+ break;
+
+ case STOP_S1: case STOP_S2: case STOP_S3:
+ case STOP_S4: case STOP_S5: case STOP_S6:
+ return MOVE_NONE;
+
+ default:
+ assert(false);
+ }
}
-
- return MOVE_NONE;
-}
-
-
-/// MovePicker::init_phase_table() initializes the PhaseTable[],
-/// MainSearchPhaseIndex, EvasionPhaseIndex, QsearchWithChecksPhaseIndex
-/// and QsearchWithoutChecksPhaseIndex variables. It is only called once
-/// during program startup, and never again while the program is running.
-
-void MovePicker::init_phase_table() {
- int i = 0;
-
- // Main search
- MainSearchPhaseIndex = i - 1;
- PhaseTable[i++] = PH_TT_MOVE;
- PhaseTable[i++] = PH_MATE_KILLER;
- PhaseTable[i++] = PH_GOOD_CAPTURES;
- // PH_KILLER_1 and PH_KILLER_2 are not yet used.
- // PhaseTable[i++] = PH_KILLER_1;
- // PhaseTable[i++] = PH_KILLER_2;
- PhaseTable[i++] = PH_NONCAPTURES;
- PhaseTable[i++] = PH_BAD_CAPTURES;
- PhaseTable[i++] = PH_STOP;
-
- // Check evasions
- EvasionsPhaseIndex = i - 1;
- PhaseTable[i++] = PH_EVASIONS;
- PhaseTable[i++] = PH_STOP;
-
- // Quiescence search with checks
- QsearchWithChecksPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCAPTURES;
- PhaseTable[i++] = PH_QCHECKS;
- PhaseTable[i++] = PH_STOP;
-
- // Quiescence search without checks
- QsearchWithoutChecksPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCAPTURES;
- PhaseTable[i++] = PH_STOP;
}
projects / stockfish / blobdiff