X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=89577ee4a58738cacca2b8aa3f023eef0c801273;hp=43f30f7709565e22502e6e94438a0aa91ac663d1;hb=c11edd3b0b43f24decc4d003472669042ae073e4;hpb=75d001adddfaa7a2eb57af99cf6c57a12913d2d1
diff --git a/src/movepick.cpp b/src/movepick.cpp
index 43f30f77..89577ee4 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -1,7 +1,7 @@
/*
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) 2008-2012 Marco Costalba, Joona Kiiski, 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
@@ -18,535 +18,347 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
+#include
#include
-#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
-
- MovePicker::MovegenPhase PhaseTable[32];
- int MainSearchPhaseIndex;
- int EvasionsPhaseIndex;
- int QsearchWithChecksPhaseIndex;
- int QsearchNoCapturesPhaseIndex;
- int QsearchWithoutChecksPhaseIndex;
- int NoMovesPhaseIndex;
-
+ enum Sequencer {
+ MAIN_SEARCH, CAPTURES_S1, KILLERS_S1, QUIETS_1_S1, QUIETS_2_S1, BAD_CAPTURES_S1,
+ EVASION, EVASIONS_S2,
+ QSEARCH_0, CAPTURES_S3, QUIET_CHECKS_S3,
+ QSEARCH_1, CAPTURES_S4,
+ PROBCUT, CAPTURES_S5,
+ RECAPTURE, CAPTURES_S6,
+ STOP
+ };
+
+ // 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& ms) { return ms.score > 0; }
+
+ // Picks and moves to the front the best move in the range [begin, end),
+ // 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* begin, MoveStack* end)
+ {
+ std::swap(*begin, *std::max_element(begin, end));
+ return begin;
+ }
}
-
-////
-//// 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 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 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[0];
- 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);
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
+ Search::Stack* s, Value beta) : pos(p), H(h), depth(d) {
+
+ assert(d > DEPTH_ZERO);
+
+ captureThreshold = 0;
+ cur = end = moves;
+ endBadCaptures = moves + MAX_MOVES - 1;
+ ss = s;
+
+ if (p.in_check())
+ phase = EVASION;
+
else
- phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
+ {
+ phase = MAIN_SEARCH;
- dc = p.discovered_check_candidates(us);
- pinned = p.pinned_pieces(p.side_to_move());
+ killers[0].move = ss->killers[0];
+ killers[1].move = ss->killers[1];
- finished = false;
+ // Consider sligtly negative captures as good if at low depth and far from beta
+ if (ss && ss->eval < beta - PawnValueMg && d < 3 * ONE_PLY)
+ captureThreshold = -PawnValueMg;
+
+ // Consider negative captures as good if still enough to reach beta
+ else if (ss && ss->eval > beta)
+ captureThreshold = beta - ss->eval;
+ }
+
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+ end += (ttMove != MOVE_NONE);
}
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
+ Square sq) : pos(p), H(h), cur(moves), end(moves) {
-/// 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 (p.in_check())
+ phase = EVASION;
- Move move;
+ else if (d > DEPTH_QS_NO_CHECKS)
+ phase = QSEARCH_0;
- while (true)
+ else if (d > DEPTH_QS_RECAPTURES)
{
- // 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;
- }
-
- // 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;
- }
+ phase = QSEARCH_1;
+
+ // 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 && !pos.is_capture_or_promotion(ttm))
+ ttm = MOVE_NONE;
}
+ else
+ {
+ phase = RECAPTURE;
+ recaptureSquare = sq;
+ ttm = MOVE_NONE;
+ }
+
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+ end += (ttMove != MOVE_NONE);
}
+MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType pt)
+ : pos(p), H(h), cur(moves), end(moves) {
-/// 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.in_check());
-Move MovePicker::get_next_move(Lock &lock) {
+ phase = 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 only captures better than parent's captured piece
+ captureThreshold = PieceValue[Mg][pt];
+ ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
- lock_release(&lock);
- return m;
+ if (ttMove && (!pos.is_capture(ttMove) || pos.see(ttMove) <= captureThreshold))
+ ttMove = MOVE_NONE;
+
+ end += (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().
+/// 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
// 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.
+ // 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;
- int seeValue;
- for (int i = 0; i < numOfMoves; i++)
+ for (MoveStack* it = moves; it != end; ++it)
{
- 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];
- }
+ m = it->move;
+ it->score = PieceValue[Mg][pos.piece_on(to_sq(m))]
+ - type_of(pos.piece_moved(m));
+
+ if (type_of(m) == PROMOTION)
+ it->score += PieceValue[Mg][promotion_type(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;
- for (int i = 0; i < numOfMoves; i++)
+ for (MoveStack* it = moves; it != end; ++it)
{
- m = moves[i].move;
-
- 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);
-
- // Ensure moves in history are always sorted as first
- if (hs > 0)
- hs += 1000;
-
- moves[i].score = hs + pos.mg_pst_delta(m);
+ m = it->move;
+ it->score = H.value(pos.piece_moved(m), to_sq(m));
}
}
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, then bad-captures and quiet
+ // moves with a negative SEE. This last group is ordered by the SEE score.
+ Move m;
+ int seeScore;
- 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);
- }
- // FIXME try psqt also here
-}
-
-void MovePicker::score_qcaptures() {
+ if (end < moves + 2)
+ return;
- // Use MVV/LVA ordering
- for (int i = 0; i < numOfMoves; i++)
+ for (MoveStack* it = moves; it != end; ++it)
{
- Move m = moves[i].move;
- if (move_promotion(m))
- moves[i].score = QueenValueMidgame;
+ m = it->move;
+ if ((seeScore = pos.see_sign(m)) < 0)
+ it->score = seeScore - History::MaxValue; // Be sure we are at the bottom
+ else if (pos.is_capture(m))
+ it->score = PieceValue[Mg][pos.piece_on(to_sq(m))]
+ - type_of(pos.piece_moved(m)) + History::MaxValue;
else
- moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
- -int(pos.type_of_piece_on(move_from(m)));
+ it->score = H.value(pos.piece_moved(m), to_sq(m));
}
}
-/// 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.
+/// MovePicker::generate_next() generates, scores and sorts the next bunch of moves,
+/// when there are no more moves to try for the current phase.
-int MovePicker::find_best_index() {
+void MovePicker::generate_next() {
- int bestScore = -10000000, bestIndex = -1;
+ cur = moves;
- for (int i = movesPicked; i < numOfMoves; i++)
- if (moves[i].score > bestScore)
- {
- bestIndex = i;
- bestScore = moves[i].score;
- }
- return bestIndex;
-}
+ switch (++phase) {
-int MovePicker::find_best_index(Bitboard* squares, int values[]) {
-
- int hs;
- Move m;
- Square to;
- int bestScore = -10000000, bestIndex = -1;
-
- for (int i = movesPicked; i < numOfMoves; i++)
- {
- m = moves[i].move;
- to = move_to(m);
-
- if (!bit_is_set(*squares, to))
- {
- // Init at first use
- set_bit(squares, to);
- values[to] = 0;
- }
-
- hs = moves[i].score - values[to];
- if (hs > bestScore)
- {
- bestIndex = i;
- bestScore = hs;
- }
- }
-
- 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;
-}
+ case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6:
+ end = generate(pos, moves);
+ score_captures();
+ return;
+ case KILLERS_S1:
+ cur = killers;
+ end = cur + 2;
+ return;
-/// 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.
+ case QUIETS_1_S1:
+ endQuiets = end = generate(pos, moves);
+ score_noncaptures();
+ end = std::partition(cur, end, has_positive_score);
+ sort(cur, end);
+ return;
-Move MovePicker::pick_move_from_list() {
+ case QUIETS_2_S1:
+ cur = end;
+ end = endQuiets;
+ if (depth >= 3 * ONE_PLY)
+ sort(cur, end);
+ return;
- int bestIndex;
- Move move;
+ case BAD_CAPTURES_S1:
+ // Just pick them in reverse order to get MVV/LVA ordering
+ cur = moves + MAX_MOVES - 1;
+ end = endBadCaptures;
+ return;
- switch (PhaseTable[phaseIndex]) {
- case PH_GOOD_CAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
+ case EVASIONS_S2:
+ end = generate(pos, moves);
+ score_evasions();
+ return;
- while (movesPicked < numOfMoves)
- {
- bestIndex = find_best_index();
+ case QUIET_CHECKS_S3:
+ end = generate(pos, moves);
+ return;
- if (bestIndex != -1) // Found a good capture
- {
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
- return move;
- }
- }
- break;
+ case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE:
+ phase = STOP;
+ case STOP:
+ end = cur + 1; // Avoid another next_phase() call
+ return;
- case PH_NONCAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
+ default:
+ assert(false);
+ }
+}
- while (movesPicked < numOfMoves)
- {
- // 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;
- if (bestIndex != -1)
- {
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
- return move;
- }
- }
- break;
+/// 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.
+template<>
+Move MovePicker::next_move() {
+
+ Move move;
- case PH_EVASIONS:
- assert(pos.is_check());
- assert(movesPicked >= 0);
+ while (true)
+ {
+ while (cur == end)
+ generate_next();
- while (movesPicked < numOfMoves)
- {
- bestIndex = find_best_index();
+ switch (phase) {
- if (bestIndex != -1)
+ case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT:
+ cur++;
+ return ttMove;
+
+ case CAPTURES_S1:
+ move = pick_best(cur++, end)->move;
+ if (move != ttMove)
{
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- return move;
+ assert(captureThreshold <= 0); // Otherwise we cannot use see_sign()
+
+ if (pos.see_sign(move) >= captureThreshold)
+ return move;
+
+ // Losing capture, move it to the tail of the array
+ (endBadCaptures--)->move = 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;
+ break;
+
+ case KILLERS_S1:
+ move = (cur++)->move;
+ if ( move != MOVE_NONE
+ && pos.is_pseudo_legal(move)
+ && move != ttMove
+ && !pos.is_capture(move))
+ return move;
+ break;
+
+ case QUIETS_1_S1: case QUIETS_2_S1:
+ move = (cur++)->move;
if ( move != ttMove
- && move != mateKiller
- && pos.pl_move_is_legal(move, pinned))
+ && move != killers[0].move
+ && move != killers[1].move)
return move;
- }
- break;
+ break;
- case PH_QCAPTURES:
- assert(!pos.is_check());
- assert(movesPicked >= 0);
- while (movesPicked < numOfMoves)
- {
- bestIndex = (movesPicked < 4 ? find_best_index() : movesPicked);
+ case BAD_CAPTURES_S1:
+ return (cur--)->move;
- if (bestIndex != -1)
- {
- 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))
- 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.pl_move_is_legal(move, pinned))
+ case EVASIONS_S2: case CAPTURES_S3: case CAPTURES_S4:
+ move = pick_best(cur++, end)->move;
+ if (move != ttMove)
return move;
- }
- break;
+ break;
- default:
- break;
- }
- return MOVE_NONE;
-}
+ case CAPTURES_S5:
+ move = pick_best(cur++, end)->move;
+ if (move != ttMove && pos.see(move) > captureThreshold)
+ return move;
+ break;
+
+ case CAPTURES_S6:
+ move = pick_best(cur++, end)->move;
+ if (to_sq(move) == recaptureSquare)
+ return move;
+ break;
+ case QUIET_CHECKS_S3:
+ move = (cur++)->move;
+ if (move != ttMove)
+ return move;
+ break;
-/// 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 {
+ case STOP:
+ return MOVE_NONE;
- return PhaseTable[phaseIndex];
+ default:
+ assert(false);
+ }
+ }
}
-/// 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;
-}
+/// Version of next_move() to use at split point nodes where the move is grabbed
+/// from the split point's shared MovePicker object. This function is not thread
+/// safe so should be lock protected by the caller.
+template<>
+Move MovePicker::next_move() { return ss->sp->mp->next_move(); }