/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
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.
-
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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
-#include "history.h"
-#include "evaluate.h"
-#include "movegen.h"
#include "movepick.h"
-#include "search.h"
-#include "value.h"
-
-
-////
-//// Local definitions
-////
+#include "thread.h"
namespace {
- /// Variables
+ enum Stages {
+ MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES,
+ EVASION, EVASIONS_INIT, ALL_EVASIONS,
+ PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES,
+ QSEARCH_WITH_CHECKS, QCAPTURES_1_INIT, QCAPTURES_1, QCHECKS,
+ QSEARCH_NO_CHECKS, QCAPTURES_2_INIT, QCAPTURES_2,
+ QSEARCH_RECAPTURES, QRECAPTURES
+ };
+
+ // Our insertion sort, which is guaranteed to be stable, as it should be
+ void insertion_sort(ExtMove* begin, ExtMove* end)
+ {
+ ExtMove tmp, *p, *q;
- MovePicker::MovegenPhase PhaseTable[32];
- int MainSearchPhaseIndex;
- int EvasionsPhaseIndex;
- int QsearchWithChecksPhaseIndex;
- int QsearchNoCapturesPhaseIndex;
- int QsearchWithoutChecksPhaseIndex;
- int NoMovesPhaseIndex;
+ for (p = begin + 1; p < end; ++p)
+ {
+ tmp = *p;
+ for (q = p; q != begin && *(q-1) < tmp; --q)
+ *q = *(q-1);
+ *q = tmp;
+ }
+ }
-}
+ // pick_best() finds the best move in the range (begin, end) and moves it to
+ // the front. It's faster than sorting all the moves in advance when there
+ // are few moves, e.g., the possible captures.
+ Move pick_best(ExtMove* begin, ExtMove* end)
+ {
+ std::swap(*begin, *std::max_element(begin, end));
+ return *begin;
+ }
+} // namespace
-////
-//// Functions
-////
+/// Constructors of 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 how important good move
+/// ordering is at the current node.
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Search::Stack* s)
+ : pos(p), ss(s), depth(d) {
-/// Constructor for the MovePicker class. Apart from the position for which
-/// it is asked to pick legal moves, MovePicker also wants some 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(const Position& p, bool pv, Move ttm,
- const SearchStack& ss, Depth d, EvalInfo* ei) : pos(p) {
- pvNode = pv;
- ttMove = ttm;
- mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller;
- killer1 = ss.killers[0];
- killer2 = ss.killers[1];
- depth = d;
- movesPicked = 0;
- numOfMoves = 0;
- numOfBadCaptures = 0;
-
- // With EvalInfo we are able to know how many captures are possible before
- // generating them. So avoid generating in case we know are zero.
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
- bool noCaptures = ei
- && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0
- && !ei->mi->specialized_eval_exists()
- && (pos.ep_square() == SQ_NONE)
- && !pos.has_pawn_on_7th(us);
-
- if (p.is_check())
- phaseIndex = EvasionsPhaseIndex;
- else if (depth > Depth(0))
- phaseIndex = MainSearchPhaseIndex;
- else if (depth == Depth(0))
- phaseIndex = (noCaptures ? QsearchNoCapturesPhaseIndex : QsearchWithChecksPhaseIndex);
- else
- phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
+ assert(d > DEPTH_ZERO);
- dc = p.discovered_check_candidates(us);
- pinned = p.pinned_pieces(p.side_to_move());
+ Square prevSq = to_sq((ss-1)->currentMove);
+ countermove = pos.this_thread()->counterMoves[pos.piece_on(prevSq)][prevSq];
- finished = false;
+ stage = pos.checkers() ? EVASION : MAIN_SEARCH;
+ ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
+ stage += (ttMove == MOVE_NONE);
}
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Square s)
+ : pos(p) {
-/// 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() {
+ if (pos.checkers())
+ stage = EVASION;
- Move move;
+ else if (d > DEPTH_QS_NO_CHECKS)
+ stage = QSEARCH_WITH_CHECKS;
- while (true)
- {
- // If we already have a list of generated moves, pick the best move from
- // the list, and return it.
- move = pick_move_from_list();
- if (move != MOVE_NONE)
- {
- assert(move_is_ok(move));
- return move;
- }
+ else if (d > DEPTH_QS_RECAPTURES)
+ stage = QSEARCH_NO_CHECKS;
- // Next phase
- phaseIndex++;
- switch (PhaseTable[phaseIndex]) {
-
- case PH_TT_MOVE:
- if (ttMove != MOVE_NONE)
- {
- assert(move_is_ok(ttMove));
- if (move_is_legal(pos, ttMove, pinned))
- return ttMove;
- }
- break;
-
- case PH_MATE_KILLER:
- if (mateKiller != MOVE_NONE)
- {
- assert(move_is_ok(mateKiller));
- if (move_is_legal(pos, mateKiller, pinned))
- return mateKiller;
- }
- break;
-
- case PH_GOOD_CAPTURES:
- numOfMoves = generate_captures(pos, moves);
- score_captures();
- movesPicked = 0;
- break;
-
- case PH_BAD_CAPTURES:
- badCapturesPicked = 0;
- break;
-
- case PH_NONCAPTURES:
- numOfMoves = generate_noncaptures(pos, moves);
- score_noncaptures();
- movesPicked = 0;
- break;
-
- case PH_EVASIONS:
- assert(pos.is_check());
- numOfMoves = generate_evasions(pos, moves);
- score_evasions();
- movesPicked = 0;
- break;
-
- case PH_QCAPTURES:
- numOfMoves = generate_captures(pos, moves);
- 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
+ {
+ stage = QSEARCH_RECAPTURES;
+ recaptureSquare = s;
+ return;
}
+
+ ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
+ stage += (ttMove == MOVE_NONE);
}
+MovePicker::MovePicker(const Position& p, Move ttm, Value th)
+ : pos(p), threshold(th) {
-/// 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.
+ assert(!pos.checkers());
-Move MovePicker::get_next_move(Lock &lock) {
+ stage = PROBCUT;
- lock_grab(&lock);
- if (finished)
- {
- lock_release(&lock);
- return MOVE_NONE;
- }
- Move m = get_next_move();
- if (m == MOVE_NONE)
- finished = true;
+ // In ProbCut we generate captures with SEE higher than or equal to the given threshold
+ ttMove = ttm
+ && pos.pseudo_legal(ttm)
+ && pos.capture(ttm)
+ && pos.see_ge(ttm, threshold)? ttm : MOVE_NONE;
- lock_release(&lock);
- return m;
+ stage += (ttMove == MOVE_NONE);
}
-/// 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 pick_move_from_list().
-
-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
- // capture, capturing a more valuable (but sufficiently defended) piece
- // 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
- // big pieces before capturing a hanging piece probably helps to reduce
- // the subtree size.
- // While scoring captures it moves all captures with negative SEE values
- // to the badCaptures[] array.
- Move m;
- int seeValue;
-
- for (int i = 0; i < numOfMoves; i++)
- {
- m = moves[i].move;
- seeValue = pos.see(m);
- if (seeValue >= 0)
- {
- if (move_promotion(m))
- moves[i].score = QueenValueMidgame;
- else
- moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
- -int(pos.type_of_piece_on(move_from(m)));
- }
- else
- {
- // Losing capture, move it to the badCaptures[] array
- assert(numOfBadCaptures < 63);
- moves[i].score = seeValue;
- badCaptures[numOfBadCaptures++] = moves[i];
- moves[i--] = moves[--numOfMoves];
- }
- }
+/// score() assigns a numerical value to each move in a move list. The moves with
+/// highest values will be picked first.
+template<>
+void MovePicker::score<CAPTURES>() {
+ // Winning and equal captures in the main search are ordered by MVV, preferring
+ // captures near our home rank. Surprisingly, this appears to perform slightly
+ // better than SEE-based move ordering: exchanging big pieces before capturing
+ // a hanging piece probably helps to reduce the subtree size.
+ // In the main search we want to push captures with negative SEE values to the
+ // badCaptures[] array, but instead of doing it now we delay until the move
+ // has been picked up, saving some SEE calls in case we get a cutoff.
+ for (auto& m : *this)
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(200 * relative_rank(pos.side_to_move(), to_sq(m)));
}
-void MovePicker::score_noncaptures() {
- // First score by history, when no history is available then use
- // piece/square tables values. This seems to be better then a
- // random choice when we don't have an history for any move.
- Move m;
- int hs;
+template<>
+void MovePicker::score<QUIETS>() {
- for (int i = 0; i < numOfMoves; i++)
- {
- m = moves[i].move;
+ const HistoryStats& history = pos.this_thread()->history;
- if (m == killer1)
- hs = HistoryMax + 2;
- else if (m == killer2)
- hs = HistoryMax + 1;
- else
- hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+ const CounterMoveStats* cmh = (ss-1)->counterMoves;
+ const CounterMoveStats* fmh = (ss-2)->counterMoves;
+ const CounterMoveStats* fmh2 = (ss-4)->counterMoves;
- // Ensure history is always preferred to pst
- if (hs > 0)
- hs += 1000;
+ Color c = pos.side_to_move();
- // pst based scoring
- moves[i].score = hs + pos.mg_pst_delta(m);
- }
+ for (auto& m : *this)
+ m.value = (*cmh)[pos.moved_piece(m)][to_sq(m)]
+ + (*fmh)[pos.moved_piece(m)][to_sq(m)]
+ + (*fmh2)[pos.moved_piece(m)][to_sq(m)]
+ + history.get(c, m);
}
-void MovePicker::score_evasions() {
+template<>
+void MovePicker::score<EVASIONS>() {
+ // Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics
+ const HistoryStats& history = pos.this_thread()->history;
+ Color c = pos.side_to_move();
- 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);
- }
+ for (auto& m : *this)
+ if (pos.capture(m))
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
+ else
+ m.value = history.get(c, 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.type_of_piece_on(move_from(m)));
- }
-}
+/// 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 value from a list of generated moves
+/// taking care not to return the ttMove if it has already been searched.
+Move MovePicker::next_move() {
-/// find_best_index() loops across the moves and returns index of
-/// the highest scored one. There is also a second version that
-/// lowers the priority of moves that attack the same square,
-/// so that if the best move that attack a square fails the next
-/// move picked attacks a different square if any, not the same one.
+ Move move;
-int MovePicker::find_best_index() {
+ switch (stage) {
- assert(movesPicked < numOfMoves);
+ case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS:
+ case QSEARCH_NO_CHECKS: case PROBCUT:
+ ++stage;
+ return ttMove;
- int bestIndex = movesPicked, bestScore = moves[movesPicked].score;
+ case CAPTURES_INIT:
+ endBadCaptures = cur = moves;
+ endMoves = generate<CAPTURES>(pos, cur);
+ score<CAPTURES>();
+ ++stage;
- for (int i = movesPicked + 1; i < numOfMoves; i++)
- if (moves[i].score > bestScore)
+ case GOOD_CAPTURES:
+ while (cur < endMoves)
{
- bestIndex = i;
- bestScore = moves[i].score;
+ move = pick_best(cur++, endMoves);
+ if (move != ttMove)
+ {
+ if (pos.see_ge(move, VALUE_ZERO))
+ return move;
+
+ // Losing capture, move it to the beginning of the array
+ *endBadCaptures++ = move;
+ }
}
- return bestIndex;
-}
-int MovePicker::find_best_index(Bitboard* squares, int values[]) {
-
- assert(movesPicked < numOfMoves);
+ ++stage;
+ move = ss->killers[0]; // First killer move
+ if ( move != MOVE_NONE
+ && move != ttMove
+ && pos.pseudo_legal(move)
+ && !pos.capture(move))
+ return move;
- int hs;
- Move m;
- Square to;
- int bestScore = -10000000, bestIndex = -1;
+ case KILLERS:
+ ++stage;
+ move = ss->killers[1]; // Second killer move
+ if ( move != MOVE_NONE
+ && move != ttMove
+ && pos.pseudo_legal(move)
+ && !pos.capture(move))
+ return move;
- for (int i = movesPicked; i < numOfMoves; i++)
- {
- m = moves[i].move;
- to = move_to(m);
+ case COUNTERMOVE:
+ ++stage;
+ move = countermove;
+ if ( move != MOVE_NONE
+ && move != ttMove
+ && move != ss->killers[0]
+ && move != ss->killers[1]
+ && pos.pseudo_legal(move)
+ && !pos.capture(move))
+ return move;
- if (!bit_is_set(*squares, to))
+ case QUIET_INIT:
+ cur = endBadCaptures;
+ endMoves = generate<QUIETS>(pos, cur);
+ score<QUIETS>();
+ if (depth < 3 * ONE_PLY)
{
- // Init at first use
- set_bit(squares, to);
- values[to] = 0;
- }
+ ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m)
+ { return m.value > VALUE_ZERO; });
+ insertion_sort(cur, goodQuiet);
+ } else
+ insertion_sort(cur, endMoves);
+ ++stage;
- hs = moves[i].score - values[to];
- if (hs > bestScore)
+ case QUIET:
+ while (cur < endMoves)
{
- bestIndex = i;
- bestScore = hs;
+ move = *cur++;
+ if ( move != ttMove
+ && move != ss->killers[0]
+ && move != ss->killers[1]
+ && move != countermove)
+ return move;
}
- }
-
- if (bestIndex != -1)
- {
- // Raise value of the picked square, so next attack
- // to the same square will get low priority.
- to = move_to(moves[bestIndex].move);
- values[to] += 0xB00;
- }
- return bestIndex;
-}
-
-
-/// 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.
-
-Move MovePicker::pick_move_from_list() {
+ ++stage;
+ cur = moves; // Point to beginning of bad captures
- int bestIndex;
- Move move;
-
- switch (PhaseTable[phaseIndex]) {
+ case BAD_CAPTURES:
+ if (cur < endBadCaptures)
+ return *cur++;
+ break;
- case PH_GOOD_CAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
+ case EVASIONS_INIT:
+ cur = moves;
+ endMoves = generate<EVASIONS>(pos, cur);
+ score<EVASIONS>();
+ ++stage;
- while (movesPicked < numOfMoves)
+ case ALL_EVASIONS:
+ while (cur < endMoves)
{
- bestIndex = find_best_index();
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
+ move = pick_best(cur++, endMoves);
+ if (move != ttMove)
return move;
}
break;
- case PH_NONCAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
+ case PROBCUT_INIT:
+ cur = moves;
+ endMoves = generate<CAPTURES>(pos, cur);
+ score<CAPTURES>();
+ ++stage;
- while (movesPicked < numOfMoves)
+ case PROBCUT_CAPTURES:
+ while (cur < endMoves)
{
- // 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.
- bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked;
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
+ move = pick_best(cur++, endMoves);
if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
+ && pos.see_ge(move, threshold))
return move;
}
break;
- case PH_EVASIONS:
- assert(pos.is_check());
- assert(movesPicked >= 0);
+ case QCAPTURES_1_INIT: case QCAPTURES_2_INIT:
+ cur = moves;
+ endMoves = generate<CAPTURES>(pos, cur);
+ score<CAPTURES>();
+ ++stage;
- while (movesPicked < numOfMoves)
- {
- bestIndex = find_best_index();
- move = moves[bestIndex].move;
- 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)
+ case QCAPTURES_1: case QCAPTURES_2:
+ while (cur < endMoves)
{
- move = badCaptures[badCapturesPicked++].move;
- if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
+ move = pick_best(cur++, endMoves);
+ if (move != ttMove)
return move;
}
- break;
-
- case PH_QCAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
- while (movesPicked < numOfMoves)
+ if (stage == QCAPTURES_2)
+ break;
+ cur = moves;
+ endMoves = generate<QUIET_CHECKS>(pos, cur);
+ ++stage;
+
+ case QCHECKS:
+ while (cur < endMoves)
{
- bestIndex = (movesPicked < 4 ? find_best_index() : movesPicked);
- move = moves[bestIndex].move;
- 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.pl_move_is_legal(move, pinned))
+ move = cur++->move;
+ if (move != ttMove)
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)
+ case QSEARCH_RECAPTURES:
+ cur = moves;
+ endMoves = generate<CAPTURES>(pos, cur);
+ score<CAPTURES>();
+ ++stage;
+
+ case QRECAPTURES:
+ while (cur < endMoves)
{
- move = moves[movesPicked++].move;
- // Remember to change the line below if we decide to hash the qsearch!
- if (/* move != ttMove && */ pos.pl_move_is_legal(move, pinned))
+ move = pick_best(cur++, endMoves);
+ if (to_sq(move) == recaptureSquare)
return move;
}
break;
default:
- break;
+ assert(false);
}
- return MOVE_NONE;
-}
-
-/// MovePicker::current_move_type() returns the type of the just
-/// picked next move. It can be used in search to further differentiate
-/// according to the current move type: capture, non capture, escape, etc.
-MovePicker::MovegenPhase MovePicker::current_move_type() const {
-
- return PhaseTable[phaseIndex];
-}
-
-
-/// MovePicker::init_phase_table() initializes the PhaseTable[],
-/// MainSearchPhaseIndex, EvasionPhaseIndex, QsearchWithChecksPhaseIndex
-/// QsearchNoCapturesPhaseIndex, QsearchWithoutChecksPhaseIndex and
-/// NoMovesPhaseIndex 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 with checks only and no captures
- QsearchNoCapturesPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCHECKS;
- PhaseTable[i++] = PH_STOP;
-
- // Quiescence search without checks
- QsearchWithoutChecksPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCAPTURES;
- PhaseTable[i++] = PH_STOP;
-
- // Do not generate any move
- NoMovesPhaseIndex = i - 1;
- PhaseTable[i++] = PH_STOP;
+ return MOVE_NONE;
}
projects / stockfish / blobdiff