X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.h;h=72932f778e9c07af6bcb9ce89e2822a8b78ddc61;hp=738fe8c9968272de24ec578a636eba5c032d37df;hb=d9caede3249698440b7579e31d92aaa9984a128b;hpb=239d7b3fd144d2b493bb47ea97a436cec8ae5990 diff --git a/src/position.h b/src/position.h index 738fe8c9..72932f77 100644 --- a/src/position.h +++ b/src/position.h @@ -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) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 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 @@ -17,7 +17,7 @@ along with this program. If not, see . */ -#if !defined(POSITION_H_INCLUDED) +#ifndef POSITION_H_INCLUDED #define POSITION_H_INCLUDED #include @@ -30,7 +30,7 @@ /// The checkInfo struct is initialized at c'tor time and keeps info used /// to detect if a move gives check. class Position; -class Thread; +struct Thread; struct CheckInfo { @@ -43,16 +43,16 @@ struct CheckInfo { }; -/// The StateInfo struct stores information we need to restore a Position +/// The 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 as a parameter. +/// is made on the board (by calling Position::do_move), a StateInfo +/// object must be passed as a parameter. struct StateInfo { Key pawnKey, materialKey; Value npMaterial[COLOR_NB]; - int castleRights, rule50, pliesFromNull; - Score psqScore; + int castlingRights, rule50, pliesFromNull; + Score psq; Square epSquare; Key key; @@ -67,39 +67,23 @@ struct StateInfo { const size_t StateCopySize64 = offsetof(StateInfo, key) / sizeof(uint64_t) + 1; -/// 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. +/// The Position class stores the information regarding the board representation +/// like pieces, side to move, hash keys, castling info, etc. The most important +/// methods are do_move() and undo_move(), used by the search to update node info +/// when traversing the search tree. class Position { public: Position() {} - Position(const Position& p, Thread* t) { *this = p; thisThread = t; } + Position(const Position& pos, Thread* t) { *this = pos; thisThread = t; } Position(const std::string& f, bool c960, Thread* t) { set(f, c960, t); } Position& operator=(const Position&); + static void init(); // Text input/output - void set(const std::string& fen, bool isChess960, Thread* th); + void set(const std::string& fenStr, bool isChess960, Thread* th); const std::string fen() const; - const std::string pretty(Move m = MOVE_NONE) const; + const std::string pretty() const; // Position representation Bitboard pieces() const; @@ -111,99 +95,93 @@ public: Piece piece_on(Square s) const; Square king_square(Color c) const; Square ep_square() const; - bool is_empty(Square s) const; - const Square* piece_list(Color c, PieceType pt) const; - int piece_count(Color c, PieceType pt) const; + bool empty(Square s) const; + template int count(Color c) const; + template const Square* list(Color c) const; // Castling - int can_castle(CastleRight f) const; int can_castle(Color c) const; - bool castle_impeded(Color c, CastlingSide s) const; - Square castle_rook_square(Color c, CastlingSide s) const; + int can_castle(CastlingRight cr) const; + bool castling_impeded(CastlingRight cr) const; + Square castling_rook_square(CastlingRight cr) const; // Checking - bool in_check() const; Bitboard checkers() const; Bitboard discovered_check_candidates() const; - Bitboard pinned_pieces() const; + Bitboard pinned_pieces(Color c) const; // Attacks to/from a given square Bitboard attackers_to(Square s) const; Bitboard attackers_to(Square s, Bitboard occ) const; - Bitboard attacks_from(Piece p, Square s) const; - static Bitboard attacks_from(Piece p, Square s, Bitboard occ); + Bitboard attacks_from(Piece pc, Square s) const; template Bitboard attacks_from(Square s) const; template Bitboard attacks_from(Square s, Color c) const; // Properties of moves - bool move_gives_check(Move m, const CheckInfo& ci) const; - bool move_is_legal(const Move m) const; - bool pl_move_is_legal(Move m, Bitboard pinned) const; - bool is_pseudo_legal(const Move m) const; - bool is_capture(Move m) const; - bool is_capture_or_promotion(Move m) const; - bool is_passed_pawn_push(Move m) const; - Piece piece_moved(Move m) const; + 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; // Piece specific - bool pawn_is_passed(Color c, Square s) const; + bool pawn_passed(Color c, Square s) const; bool pawn_on_7th(Color c) const; - bool opposite_bishops() const; bool bishop_pair(Color c) const; + bool opposite_bishops() const; // Doing and undoing moves void do_move(Move m, StateInfo& st); void do_move(Move m, StateInfo& st, const CheckInfo& ci, bool moveIsCheck); void undo_move(Move m); - template void do_null_move(StateInfo& st); + 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 key() const; + Key key_after(Move m) const; Key exclusion_key() const; Key pawn_key() const; Key material_key() const; // Incremental piece-square evaluation Score psq_score() const; - Score psq_delta(Piece p, Square from, Square to) const; Value non_pawn_material(Color c) const; // Other properties of the position Color side_to_move() const; - int startpos_ply_counter() const; + Phase game_phase() const; + int game_ply() const; bool is_chess960() const; Thread* this_thread() const; - int64_t nodes_searched() const; - void set_nodes_searched(int64_t n); - template bool is_draw() const; + uint64_t nodes_searched() const; + void set_nodes_searched(uint64_t n); + bool is_draw() const; // Position consistency check, for debugging - bool pos_is_ok(int* failedStep = NULL) const; + bool pos_is_ok(int* step = NULL) const; void flip(); private: // Initialization helpers (used while setting up a position) void clear(); - void put_piece(Piece p, Square s); - void set_castle_right(Color c, Square rfrom); - - // Helper template functions - template void do_castle_move(Move m); - template Bitboard hidden_checkers() const; + void set_castling_right(Color c, Square rfrom); + void set_state(StateInfo* si) 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 - Score compute_psq_score() const; - Value compute_non_pawn_material(Color c) const; + // Helper functions + Bitboard check_blockers(Color c, Color kingColor) const; + void put_piece(Square s, Color c, PieceType pt); + void remove_piece(Square s, Color c, PieceType pt); + void move_piece(Square from, Square to, Color c, PieceType pt); + template + void do_castling(Square from, Square& to, Square& rfrom, Square& rto); // Board and pieces Piece board[SQUARE_NB]; @@ -214,23 +192,23 @@ private: int index[SQUARE_NB]; // Other info - int castleRightsMask[SQUARE_NB]; - Square castleRookSquare[COLOR_NB][CASTLING_SIDE_NB]; - Bitboard castlePath[COLOR_NB][CASTLING_SIDE_NB]; + int castlingRightsMask[SQUARE_NB]; + Square castlingRookSquare[CASTLING_RIGHT_NB]; + Bitboard castlingPath[CASTLING_RIGHT_NB]; StateInfo startState; - int64_t nodes; - int startPosPly; + uint64_t nodes; + int gamePly; Color sideToMove; Thread* thisThread; StateInfo* st; - int chess960; + bool chess960; }; -inline int64_t Position::nodes_searched() const { +inline uint64_t Position::nodes_searched() const { return nodes; } -inline void Position::set_nodes_searched(int64_t n) { +inline void Position::set_nodes_searched(uint64_t n) { nodes = n; } @@ -238,11 +216,11 @@ inline Piece Position::piece_on(Square s) const { return board[s]; } -inline Piece Position::piece_moved(Move m) const { +inline Piece Position::moved_piece(Move m) const { return board[from_sq(m)]; } -inline bool Position::is_empty(Square s) const { +inline bool Position::empty(Square s) const { return board[s] == NO_PIECE; } @@ -274,12 +252,12 @@ inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]); } -inline int Position::piece_count(Color c, PieceType pt) const { - return pieceCount[c][pt]; +template inline int Position::count(Color c) const { + return pieceCount[c][Pt]; } -inline const Square* Position::piece_list(Color c, PieceType pt) const { - return pieceList[c][pt]; +template inline const Square* Position::list(Color c) const { + return pieceList[c][Pt]; } inline Square Position::ep_square() const { @@ -290,26 +268,26 @@ inline Square Position::king_square(Color c) const { return pieceList[c][KING][0]; } -inline int Position::can_castle(CastleRight f) const { - return st->castleRights & f; +inline int Position::can_castle(CastlingRight cr) const { + return st->castlingRights & cr; } inline int Position::can_castle(Color c) const { - return st->castleRights & ((WHITE_OO | WHITE_OOO) << (2 * c)); + return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c)); } -inline bool Position::castle_impeded(Color c, CastlingSide s) const { - return byTypeBB[ALL_PIECES] & castlePath[c][s]; +inline bool Position::castling_impeded(CastlingRight cr) const { + return byTypeBB[ALL_PIECES] & castlingPath[cr]; } -inline Square Position::castle_rook_square(Color c, CastlingSide s) const { - return castleRookSquare[c][s]; +inline Square Position::castling_rook_square(CastlingRight cr) const { + return castlingRookSquare[cr]; } template inline Bitboard Position::attacks_from(Square s) const { - return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, pieces()) + return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, byTypeBB[ALL_PIECES]) : Pt == QUEEN ? attacks_from(s) | attacks_from(s) : StepAttacksBB[Pt][s]; } @@ -319,8 +297,8 @@ inline Bitboard Position::attacks_from(Square s, Color c) const { return StepAttacksBB[make_piece(c, PAWN)][s]; } -inline Bitboard Position::attacks_from(Piece p, Square s) const { - return attacks_from(p, s, byTypeBB[ALL_PIECES]); +inline Bitboard Position::attacks_from(Piece pc, Square s) const { + return attacks_bb(pc, s, byTypeBB[ALL_PIECES]); } inline Bitboard Position::attackers_to(Square s) const { @@ -331,28 +309,25 @@ inline Bitboard Position::checkers() const { return st->checkersBB; } -inline bool Position::in_check() const { - return st->checkersBB != 0; -} - inline Bitboard Position::discovered_check_candidates() const { - return hidden_checkers(); + return check_blockers(sideToMove, ~sideToMove); } -inline Bitboard Position::pinned_pieces() const { - return hidden_checkers(); +inline Bitboard Position::pinned_pieces(Color c) const { + return check_blockers(c, c); } -inline bool Position::pawn_is_passed(Color c, Square s) const { +inline bool Position::pawn_passed(Color c, Square s) const { return !(pieces(~c, PAWN) & passed_pawn_mask(c, s)); } -inline Key Position::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::exclusion_key() const { - return st->key ^ Zobrist::exclusion; +inline Key Position::key() const { + return st->key; } inline Key Position::pawn_key() const { @@ -363,26 +338,16 @@ inline Key Position::material_key() const { return st->materialKey; } -inline Score Position::psq_delta(Piece p, Square from, Square to) const { - return pieceSquareTable[p][to] - pieceSquareTable[p][from]; -} - inline Score Position::psq_score() const { - return st->psqScore; + return st->psq; } inline Value Position::non_pawn_material(Color c) const { return st->npMaterial[c]; } -inline bool Position::is_passed_pawn_push(Move m) const { - - return type_of(piece_moved(m)) == PAWN - && pawn_is_passed(sideToMove, to_sq(m)); -} - -inline int Position::startpos_ply_counter() const { - return startPosPly + st->pliesFromNull; // HACK +inline int Position::game_ply() const { + return gamePly; } inline bool Position::opposite_bishops() const { @@ -406,17 +371,17 @@ inline bool Position::is_chess960() const { return chess960; } -inline bool Position::is_capture_or_promotion(Move m) const { +inline bool Position::capture_or_promotion(Move m) const { assert(is_ok(m)); - return type_of(m) ? type_of(m) != CASTLE : !is_empty(to_sq(m)); + return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m)); } -inline bool Position::is_capture(Move m) const { +inline bool Position::capture(Move m) const { - // Note that castle is coded as "king captures the rook" + // Note that castling is encoded as "king captures the rook" assert(is_ok(m)); - return (!is_empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT; + return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT; } inline PieceType Position::captured_piece_type() const { @@ -427,4 +392,44 @@ inline Thread* Position::this_thread() const { return thisThread; } -#endif // !defined(POSITION_H_INCLUDED) +inline void Position::put_piece(Square s, Color c, PieceType pt) { + + 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; +} + +inline void Position::move_piece(Square from, Square to, Color c, PieceType pt) { + + // 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; +} + +inline void Position::remove_piece(Square s, Color c, PieceType pt) { + + // 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, will be overwritten by capturing + 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; +} + +#endif // #ifndef POSITION_H_INCLUDED