X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.h;h=b2538e96b5cf9316dc2907bbfe43aec9d929dcc3;hp=5935181b5bf704fe7a41e83ee877756a892a7ff0;hb=ca14345ba26fc40e1039029659f57028f510502f;hpb=5b7a141065194da0b6640c3b4b27911a67557e21 diff --git a/src/position.h b/src/position.h index 5935181b..b2538e96 100644 --- a/src/position.h +++ b/src/position.h @@ -1,7 +1,8 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2016 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 @@ -17,532 +18,422 @@ along with this program. If not, see . */ -#if !defined(POSITION_H_INCLUDED) +#ifndef POSITION_H_INCLUDED #define POSITION_H_INCLUDED #include +#include // For offsetof() +#include +#include // For std::unique_ptr +#include +#include #include "bitboard.h" -#include "move.h" #include "types.h" -/// Maximum number of plies per game (220 should be enough, because the -/// maximum search depth is 100, and during position setup we reset the -/// move counter for every non-reversible move). -const int MaxGameLength = 220; - class Position; +class Thread; -/// struct checkInfo is initialized at c'tor time and keeps -/// info used to detect if a move gives check. +namespace PSQT { -struct CheckInfo { + extern Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; - explicit CheckInfo(const Position&); + void init(); +} - Bitboard dcCandidates; - Bitboard checkSq[8]; - Square ksq; -}; +/// CheckInfo struct is initialized at constructor time and keeps info used to +/// detect if a move gives check. -/// Castle rights, encoded as bit fields +struct CheckInfo { -enum CastleRights { - CASTLES_NONE = 0, - WHITE_OO = 1, - BLACK_OO = 2, - WHITE_OOO = 4, - BLACK_OOO = 8, - ALL_CASTLES = 15 -}; + explicit CheckInfo(const Position&); -/// Game phase -enum Phase { - PHASE_ENDGAME = 0, - PHASE_MIDGAME = 128 + Bitboard dcCandidates; + Bitboard pinned; + Bitboard checkSquares[PIECE_TYPE_NB]; + Square ksq; }; -/// The StateInfo struct stores information we need to restore a Position -/// object to its previous state when we retract a move. Whenever a move -/// is made on the board (by calling Position::do_move), an StateInfo object -/// must be passed as a parameter. +/// StateInfo struct stores information needed to restore a Position object to +/// its previous state when we retract a move. Whenever a move is made on the +/// board (by calling Position::do_move), a StateInfo object must be passed. struct StateInfo { - Key pawnKey, materialKey; - int castleRights, rule50, gamePly, pliesFromNull; + + // Copied when making a move + Key pawnKey; + Key materialKey; + Value nonPawnMaterial[COLOR_NB]; + int castlingRights; + int rule50; + int pliesFromNull; + Score psq; Square epSquare; - Score value; - Value npMaterial[2]; - PieceType capturedType; - Key key; - Bitboard checkersBB; + // Not copied when making a move + Key key; + Bitboard checkersBB; + PieceType capturedType; StateInfo* previous; }; +// In a std::deque references to elements are unaffected upon resizing +typedef std::unique_ptr> StateListPtr; -/// The position data structure. A position consists of the following data: -/// -/// * For each piece type, a bitboard representing the squares occupied -/// by pieces of that type. -/// * For each color, a bitboard representing the squares occupied by -/// pieces of that color. -/// * A bitboard of all occupied squares. -/// * A bitboard of all checking pieces. -/// * A 64-entry array of pieces, indexed by the squares of the board. -/// * The current side to move. -/// * Information about the castling rights for both sides. -/// * The initial files of the kings and both pairs of rooks. This is -/// used to implement the Chess960 castling rules. -/// * The en passant square (which is SQ_NONE if no en passant capture is -/// possible). -/// * The squares of the kings for both sides. -/// * Hash keys for the position itself, the current pawn structure, and -/// the current material situation. -/// * Hash keys for all previous positions in the game for detecting -/// repetition draws. -/// * A counter for detecting 50 move rule draws. -class Position { +/// Position class stores information regarding the board representation as +/// pieces, side to move, hash keys, castling info, etc. Important methods are +/// do_move() and undo_move(), used by the search to update node info when +/// traversing the search tree. - Position(); // No default or copy c'tor allowed - Position(const Position& pos); +class Position { public: - enum GamePhase { - MidGame, - EndGame - }; + static void init(); - // Constructors - Position(const Position& pos, int threadID); - Position(const std::string& fen, bool isChess960, int threadID); + Position() = default; + Position(const Position&) = delete; + Position& operator=(const Position&) = delete; - // Text input/output - void from_fen(const std::string& fen, bool isChess960); - const std::string to_fen() const; - void print(Move m = MOVE_NONE) const; - - // Copying - void flip(); - - // The piece on a given square - Piece piece_on(Square s) const; - PieceType type_of_piece_on(Square s) const; - Color color_of_piece_on(Square s) const; - bool square_is_empty(Square s) const; - bool square_is_occupied(Square s) const; - Value midgame_value_of_piece_on(Square s) const; - Value endgame_value_of_piece_on(Square s) const; - - // Side to move - Color side_to_move() const; + // FEN string input/output + Position& set(const std::string& fenStr, bool isChess960, StateInfo* si, Thread* th); + const std::string fen() const; - // Bitboard representation of the position - Bitboard empty_squares() const; - Bitboard occupied_squares() const; - Bitboard pieces_of_color(Color c) const; + // Position representation + Bitboard pieces() const; Bitboard pieces(PieceType pt) const; - Bitboard pieces(PieceType pt, Color c) const; Bitboard pieces(PieceType pt1, PieceType pt2) const; - Bitboard pieces(PieceType pt1, PieceType pt2, Color c) const; - - // Number of pieces of each color and type - int piece_count(Color c, PieceType pt) const; - - // The en passant square + Bitboard pieces(Color c) const; + Bitboard pieces(Color c, PieceType pt) const; + Bitboard pieces(Color c, PieceType pt1, PieceType pt2) const; + Piece piece_on(Square s) const; Square ep_square() const; - - // Current king position for each color - Square king_square(Color c) const; - - // Castling rights - bool can_castle_kingside(Color c) const; - bool can_castle_queenside(Color c) const; - bool can_castle(Color c) const; - Square initial_kr_square(Color c) const; - Square initial_qr_square(Color c) const; - - // Bitboards for pinned pieces and discovered check candidates - Bitboard discovered_check_candidates(Color c) const; - Bitboard pinned_pieces(Color c) const; - - // Checking pieces and under check information + bool empty(Square s) const; + template int count(Color c) const; + template const Square* squares(Color c) const; + template Square square(Color c) const; + + // Castling + int can_castle(Color c) const; + int can_castle(CastlingRight cr) const; + bool castling_impeded(CastlingRight cr) const; + Square castling_rook_square(CastlingRight cr) const; + + // Checking Bitboard checkers() const; - bool in_check() const; - - // Piece lists - Square piece_list(Color c, PieceType pt, int index) const; - const Square* piece_list_begin(Color c, PieceType pt) const; + Bitboard discovered_check_candidates() const; + Bitboard pinned_pieces(Color c) const; - // Information about attacks to or from a given square + // Attacks to/from a given square Bitboard attackers_to(Square s) const; - Bitboard attacks_from(Piece p, Square s) const; - static Bitboard attacks_from(Piece p, Square s, Bitboard occ); + Bitboard attackers_to(Square s, Bitboard occupied) const; + Bitboard attacks_from(Piece pc, Square s) const; template Bitboard attacks_from(Square s) const; template Bitboard attacks_from(Square s, Color c) const; + Bitboard slider_blockers(Bitboard target, Bitboard sliders, Square s) const; // Properties of moves - bool pl_move_is_legal(Move m, Bitboard pinned) const; - bool pl_move_is_evasion(Move m, Bitboard pinned) const; - bool move_is_legal(const Move m) const; - bool move_is_legal(const Move m, Bitboard pinned) const; - bool move_gives_check(Move m) const; - bool move_gives_check(Move m, const CheckInfo& ci) const; - bool move_is_capture(Move m) const; - bool move_is_passed_pawn_push(Move m) const; - bool move_attacks_square(Move m, Square s) const; - - // Piece captured with previous moves + bool legal(Move m, Bitboard pinned) const; + bool pseudo_legal(const Move m) const; + bool capture(Move m) const; + bool capture_or_promotion(Move m) const; + bool gives_check(Move m, const CheckInfo& ci) const; + bool advanced_pawn_push(Move m) const; + Piece moved_piece(Move m) const; PieceType captured_piece_type() const; - // Information about pawns - bool pawn_is_passed(Color c, Square s) const; - - // Weak squares - bool square_is_weak(Square s, Color c) const; + // Piece specific + bool pawn_passed(Color c, Square s) const; + bool opposite_bishops() const; // Doing and undoing moves - void do_setup_move(Move m); - void do_move(Move m, StateInfo& st); - void do_move(Move m, StateInfo& st, const CheckInfo& ci, bool moveIsCheck); + void do_move(Move m, StateInfo& st, bool givesCheck); void undo_move(Move m); void do_null_move(StateInfo& st); void undo_null_move(); // Static exchange evaluation - int see(Move m) const; - int see_sign(Move m) const; + Value see(Move m) const; + Value see_sign(Move m) const; // Accessing hash keys - Key get_key() const; - Key get_exclusion_key() const; - Key get_pawn_key() const; - Key get_material_key() const; - - // Incremental evaluation - Score value() const; - Value non_pawn_material(Color c) const; - static Score pst_delta(Piece piece, Square from, Square to); - - // Game termination checks - bool is_mate() const; - bool is_draw() const; - - // Number of plies from starting position - int startpos_ply_counter() const; + Key key() const; + Key key_after(Move m) const; + Key exclusion_key() const; + Key material_key() const; + Key pawn_key() const; // Other properties of the position - bool opposite_colored_bishops() const; - bool has_pawn_on_7th(Color c) const; + Color side_to_move() const; + Phase game_phase() const; + int game_ply() const; bool is_chess960() const; - - // Current thread ID searching on the position - int thread() const; - - int64_t nodes_searched() const; - void set_nodes_searched(int64_t n); + Thread* this_thread() const; + uint64_t nodes_searched() const; + void set_nodes_searched(uint64_t n); + bool is_draw() const; + int rule50_count() const; + Score psq_score() const; + Value non_pawn_material(Color c) const; // Position consistency check, for debugging - bool is_ok(int* failedStep = NULL) const; - - // Static member functions - static void init_zobrist(); - static void init_piece_square_tables(); + bool pos_is_ok(int* failedStep = nullptr) const; + void flip(); private: - - // Initialization helper functions (used while setting up a position) - void clear(); - void detach(); - void put_piece(Piece p, Square s); - void do_allow_oo(Color c); - void do_allow_ooo(Color c); - bool set_castling_rights(char token); - - // Helper functions for doing and undoing moves - void do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep); - void do_castle_move(Move m); - void undo_castle_move(Move m); - void find_checkers(); - - template - Bitboard hidden_checkers(Color c) const; - - // Computing hash keys from scratch (for initialization and debugging) - Key compute_key() const; - Key compute_pawn_key() const; - Key compute_material_key() const; - - // Computing incremental evaluation scores and material counts - static Score pst(Color c, PieceType pt, Square s); - Score compute_value() const; - Value compute_non_pawn_material(Color c) const; - - // Board - Piece board[64]; - - // Bitboards - Bitboard byTypeBB[8], byColorBB[2]; - - // Piece counts - int pieceCount[2][8]; // [color][pieceType] - - // Piece lists - Square pieceList[2][8][16]; // [color][pieceType][index] - int index[64]; // [square] - - // Other info + // Initialization helpers (used while setting up a position) + void set_castling_right(Color c, Square rfrom); + void set_state(StateInfo* si) const; + + // Other helpers + void put_piece(Color c, PieceType pt, Square s); + void remove_piece(Color c, PieceType pt, Square s); + void move_piece(Color c, PieceType pt, Square from, Square to); + template + void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto); + + // Data members + Piece board[SQUARE_NB]; + Bitboard byTypeBB[PIECE_TYPE_NB]; + Bitboard byColorBB[COLOR_NB]; + int pieceCount[COLOR_NB][PIECE_TYPE_NB]; + Square pieceList[COLOR_NB][PIECE_TYPE_NB][16]; + int index[SQUARE_NB]; + int castlingRightsMask[SQUARE_NB]; + Square castlingRookSquare[CASTLING_RIGHT_NB]; + Bitboard castlingPath[CASTLING_RIGHT_NB]; + uint64_t nodes; + int gamePly; Color sideToMove; - Key history[MaxGameLength]; - int castleRightsMask[64]; - StateInfo startState; - File initialKFile, initialKRFile, initialQRFile; - bool chess960; - int startPosPlyCounter; - int threadID; - int64_t nodes; + Thread* thisThread; StateInfo* st; - - // Static variables - static Key zobrist[2][8][64]; - static Key zobEp[64]; - static Key zobCastle[16]; - static Key zobSideToMove; - static Score PieceSquareTable[16][64]; - static Key zobExclusion; - static const Value seeValues[8]; - static const Value PieceValueMidgame[17]; - static const Value PieceValueEndgame[17]; + bool chess960; }; -inline int64_t Position::nodes_searched() const { - return nodes; +extern std::ostream& operator<<(std::ostream& os, const Position& pos); + +inline Color Position::side_to_move() const { + return sideToMove; } -inline void Position::set_nodes_searched(int64_t n) { - nodes = n; +inline bool Position::empty(Square s) const { + return board[s] == NO_PIECE; } inline Piece Position::piece_on(Square s) const { return board[s]; } -inline Color Position::color_of_piece_on(Square s) const { - return color_of_piece(piece_on(s)); -} - -inline PieceType Position::type_of_piece_on(Square s) const { - return type_of_piece(piece_on(s)); -} - -inline bool Position::square_is_empty(Square s) const { - return piece_on(s) == PIECE_NONE; -} - -inline bool Position::square_is_occupied(Square s) const { - return !square_is_empty(s); +inline Piece Position::moved_piece(Move m) const { + return board[from_sq(m)]; } -inline Value Position::midgame_value_of_piece_on(Square s) const { - return PieceValueMidgame[piece_on(s)]; -} - -inline Value Position::endgame_value_of_piece_on(Square s) const { - return PieceValueEndgame[piece_on(s)]; -} - -inline Color Position::side_to_move() const { - return sideToMove; -} - -inline Bitboard Position::occupied_squares() const { - return byTypeBB[0]; -} - -inline Bitboard Position::empty_squares() const { - return ~occupied_squares(); -} - -inline Bitboard Position::pieces_of_color(Color c) const { - return byColorBB[c]; +inline Bitboard Position::pieces() const { + return byTypeBB[ALL_PIECES]; } inline Bitboard Position::pieces(PieceType pt) const { return byTypeBB[pt]; } -inline Bitboard Position::pieces(PieceType pt, Color c) const { - return byTypeBB[pt] & byColorBB[c]; -} - inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const { return byTypeBB[pt1] | byTypeBB[pt2]; } -inline Bitboard Position::pieces(PieceType pt1, PieceType pt2, Color c) const { - return (byTypeBB[pt1] | byTypeBB[pt2]) & byColorBB[c]; -} - -inline int Position::piece_count(Color c, PieceType pt) const { - return pieceCount[c][pt]; +inline Bitboard Position::pieces(Color c) const { + return byColorBB[c]; } -inline Square Position::piece_list(Color c, PieceType pt, int idx) const { - return pieceList[c][pt][idx]; +inline Bitboard Position::pieces(Color c, PieceType pt) const { + return byColorBB[c] & byTypeBB[pt]; } -inline const Square* Position::piece_list_begin(Color c, PieceType pt) const { - return pieceList[c][pt]; +inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { + return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]); } -inline Square Position::ep_square() const { - return st->epSquare; +template inline int Position::count(Color c) const { + return pieceCount[c][Pt]; } -inline Square Position::king_square(Color c) const { - return pieceList[c][KING][0]; +template inline const Square* Position::squares(Color c) const { + return pieceList[c][Pt]; } -inline bool Position::can_castle_kingside(Color side) const { - return st->castleRights & (1+int(side)); +template inline Square Position::square(Color c) const { + assert(pieceCount[c][Pt] == 1); + return pieceList[c][Pt][0]; } -inline bool Position::can_castle_queenside(Color side) const { - return st->castleRights & (4+4*int(side)); +inline Square Position::ep_square() const { + return st->epSquare; } -inline bool Position::can_castle(Color side) const { - return can_castle_kingside(side) || can_castle_queenside(side); +inline int Position::can_castle(CastlingRight cr) const { + return st->castlingRights & cr; } -inline Square Position::initial_kr_square(Color c) const { - return relative_square(c, make_square(initialKRFile, RANK_1)); +inline int Position::can_castle(Color c) const { + return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c)); } -inline Square Position::initial_qr_square(Color c) const { - return relative_square(c, make_square(initialQRFile, RANK_1)); +inline bool Position::castling_impeded(CastlingRight cr) const { + return byTypeBB[ALL_PIECES] & castlingPath[cr]; } -template<> -inline Bitboard Position::attacks_from(Square s, Color c) const { - return StepAttacksBB[make_piece(c, PAWN)][s]; +inline Square Position::castling_rook_square(CastlingRight cr) const { + return castlingRookSquare[cr]; } -template // Knight and King and white pawns +template inline Bitboard Position::attacks_from(Square s) const { - return StepAttacksBB[Piece][s]; + return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, byTypeBB[ALL_PIECES]) + : Pt == QUEEN ? attacks_from(s) | attacks_from(s) + : StepAttacksBB[Pt][s]; } template<> -inline Bitboard Position::attacks_from(Square s) const { - return bishop_attacks_bb(s, occupied_squares()); +inline Bitboard Position::attacks_from(Square s, Color c) const { + return StepAttacksBB[make_piece(c, PAWN)][s]; } -template<> -inline Bitboard Position::attacks_from(Square s) const { - return rook_attacks_bb(s, occupied_squares()); +inline Bitboard Position::attacks_from(Piece pc, Square s) const { + return attacks_bb(pc, s, byTypeBB[ALL_PIECES]); } -template<> -inline Bitboard Position::attacks_from(Square s) const { - return attacks_from(s) | attacks_from(s); +inline Bitboard Position::attackers_to(Square s) const { + return attackers_to(s, byTypeBB[ALL_PIECES]); } inline Bitboard Position::checkers() const { return st->checkersBB; } -inline bool Position::in_check() const { - return st->checkersBB != EmptyBoardBB; +inline Bitboard Position::discovered_check_candidates() const { + return slider_blockers(pieces(sideToMove), pieces(sideToMove), square(~sideToMove)); } -inline bool Position::pawn_is_passed(Color c, Square s) const { - return !(pieces(PAWN, opposite_color(c)) & passed_pawn_mask(c, s)); +inline Bitboard Position::pinned_pieces(Color c) const { + return slider_blockers(pieces(c), pieces(~c), square(c)); } -inline bool Position::square_is_weak(Square s, Color c) const { - return !(pieces(PAWN, opposite_color(c)) & attack_span_mask(c, s)); +inline bool Position::pawn_passed(Color c, Square s) const { + return !(pieces(~c, PAWN) & passed_pawn_mask(c, s)); } -inline Key Position::get_key() const { - return st->key; +inline bool Position::advanced_pawn_push(Move m) const { + return type_of(moved_piece(m)) == PAWN + && relative_rank(sideToMove, from_sq(m)) > RANK_4; } -inline Key Position::get_exclusion_key() const { - return st->key ^ zobExclusion; +inline Key Position::key() const { + return st->key; } -inline Key Position::get_pawn_key() const { +inline Key Position::pawn_key() const { return st->pawnKey; } -inline Key Position::get_material_key() const { +inline Key Position::material_key() const { return st->materialKey; } -inline Score Position::pst(Color c, PieceType pt, Square s) { - return PieceSquareTable[make_piece(c, pt)][s]; -} - -inline Score Position::pst_delta(Piece piece, Square from, Square to) { - return PieceSquareTable[piece][to] - PieceSquareTable[piece][from]; -} - -inline Score Position::value() const { - return st->value; +inline Score Position::psq_score() const { + return st->psq; } inline Value Position::non_pawn_material(Color c) const { - return st->npMaterial[c]; + return st->nonPawnMaterial[c]; } -inline bool Position::move_is_passed_pawn_push(Move m) const { - - Color c = side_to_move(); - return piece_on(move_from(m)) == make_piece(c, PAWN) - && pawn_is_passed(c, move_to(m)); +inline int Position::game_ply() const { + return gamePly; } -inline int Position::startpos_ply_counter() const { - return startPosPlyCounter; +inline int Position::rule50_count() const { + return st->rule50; } -inline bool Position::opposite_colored_bishops() const { +inline uint64_t Position::nodes_searched() const { + return nodes; +} - return piece_count(WHITE, BISHOP) == 1 && piece_count(BLACK, BISHOP) == 1 - && opposite_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0)); +inline void Position::set_nodes_searched(uint64_t n) { + nodes = n; } -inline bool Position::has_pawn_on_7th(Color c) const { - return pieces(PAWN, c) & rank_bb(relative_rank(c, RANK_7)); +inline bool Position::opposite_bishops() const { + return pieceCount[WHITE][BISHOP] == 1 + && pieceCount[BLACK][BISHOP] == 1 + && opposite_colors(square(WHITE), square(BLACK)); } inline bool Position::is_chess960() const { return chess960; } -inline bool Position::move_is_capture(Move m) const { +inline bool Position::capture_or_promotion(Move m) const { - assert (m != MOVE_NONE && m != MOVE_NULL); - return !move_is_special(m) ? !square_is_empty(move_to(m)) : move_is_ep(m); + assert(is_ok(m)); + return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m)); +} + +inline bool Position::capture(Move m) const { + + // Castling is encoded as "king captures the rook" + assert(is_ok(m)); + return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT; } inline PieceType Position::captured_piece_type() const { return st->capturedType; } -inline int Position::thread() const { - return threadID; +inline Thread* Position::this_thread() const { + return thisThread; +} + +inline void Position::put_piece(Color c, PieceType pt, Square s) { + + board[s] = make_piece(c, pt); + byTypeBB[ALL_PIECES] |= s; + byTypeBB[pt] |= s; + byColorBB[c] |= s; + index[s] = pieceCount[c][pt]++; + pieceList[c][pt][index[s]] = s; + pieceCount[c][ALL_PIECES]++; } -inline void Position::do_allow_oo(Color c) { - st->castleRights |= (1 + int(c)); +inline void Position::remove_piece(Color c, PieceType pt, Square s) { + + // WARNING: This is not a reversible operation. If we remove a piece in + // do_move() and then replace it in undo_move() we will put it at the end of + // the list and not in its original place, it means index[] and pieceList[] + // are not guaranteed to be invariant to a do_move() + undo_move() sequence. + byTypeBB[ALL_PIECES] ^= s; + byTypeBB[pt] ^= s; + byColorBB[c] ^= s; + /* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */ + Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]]; + index[lastSquare] = index[s]; + pieceList[c][pt][index[lastSquare]] = lastSquare; + pieceList[c][pt][pieceCount[c][pt]] = SQ_NONE; + pieceCount[c][ALL_PIECES]--; } -inline void Position::do_allow_ooo(Color c) { - st->castleRights |= (4 + 4*int(c)); +inline void Position::move_piece(Color c, PieceType pt, Square from, Square to) { + + // index[from] is not updated and becomes stale. This works as long as index[] + // is accessed just by known occupied squares. + Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[pt] ^= from_to_bb; + byColorBB[c] ^= from_to_bb; + board[from] = NO_PIECE; + board[to] = make_piece(c, pt); + index[to] = index[from]; + pieceList[c][pt][index[to]] = to; } -#endif // !defined(POSITION_H_INCLUDED) +#endif // #ifndef POSITION_H_INCLUDED