/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-#if !defined(POSITION_H_INCLUDED)
+#ifndef POSITION_H_INCLUDED
#define POSITION_H_INCLUDED
-// Disable some silly and noisy warning from MSVC compiler
-#if defined(_MSC_VER)
-
-// Forcing value to bool 'true' or 'false' (performance warning)
-#pragma warning(disable: 4800)
-
-// Conditional expression is constant
-#pragma warning(disable: 4127)
-
-
-#endif
-
-////
-//// Includes
-////
+#include <cassert>
+#include <deque>
+#include <memory> // For std::unique_ptr
+#include <string>
#include "bitboard.h"
-#include "color.h"
-#include "direction.h"
-#include "move.h"
-#include "piece.h"
-#include "square.h"
-#include "value.h"
+#include "evaluate.h"
+#include "types.h"
+#include "nnue/nnue_accumulator.h"
-////
-//// Constants
-////
-/// FEN string for the initial position
-const std::string StartPosition = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
+/// 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.
-/// 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;
-
-
-////
-//// Types
-////
-
-/// Castle rights, encoded as bit fields
-
-enum CastleRights {
- NO_CASTLES = 0,
- WHITE_OO = 1,
- BLACK_OO = 2,
- WHITE_OOO = 4,
- BLACK_OOO = 8,
- ALL_CASTLES = 15
-};
+struct StateInfo {
-/// Game phase
-enum Phase {
- PHASE_ENDGAME = 0,
- PHASE_MIDGAME = 128
+ // Copied when making a move
+ Key pawnKey;
+ Key materialKey;
+ Value nonPawnMaterial[COLOR_NB];
+ int castlingRights;
+ int rule50;
+ int pliesFromNull;
+ Square epSquare;
+
+ // Not copied when making a move (will be recomputed anyhow)
+ Key key;
+ Bitboard checkersBB;
+ Piece capturedPiece;
+ StateInfo* previous;
+ Bitboard blockersForKing[COLOR_NB];
+ Bitboard pinners[COLOR_NB];
+ Bitboard checkSquares[PIECE_TYPE_NB];
+ int repetition;
+
+ // Used by NNUE
+ Eval::NNUE::Accumulator accumulator;
+ DirtyPiece dirtyPiece;
};
-/// 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.
-
-struct StateInfo {
- Key key, pawnKey, materialKey;
- int castleRights, rule50;
- Square kingSquare[2], epSquare;
- Value mgValue, egValue;
- Value npMaterial[2];
-
- PieceType capture;
- Bitboard checkersBB;
- StateInfo* previous;
-};
+/// A list to keep track of the position states along the setup moves (from the
+/// start position to the position just before the search starts). Needed by
+/// 'draw by repetition' detection. Use a std::deque because pointers to
+/// elements are not invalidated upon list resizing.
+typedef std::unique_ptr<std::deque<StateInfo>> 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.
+/// 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.
+class Thread;
class Position {
+public:
+ static void init();
- friend class MaterialInfo;
- friend class EndgameFunctions;
+ Position() = default;
+ Position(const Position&) = delete;
+ Position& operator=(const Position&) = delete;
-public:
- enum GamePhase {
- MidGame,
- EndGame
- };
-
- // Constructors
- Position() {}
- Position(const Position& pos);
- Position(const std::string& fen);
-
- // Text input/output
- void from_fen(const std::string& fen);
- const std::string to_fen() const;
- void print(Move m = MOVE_NONE) const;
-
- // Copying
- void copy(const Position& pos);
- void flipped_copy(const Position& pos);
-
- // 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);
+ Position& set(const std::string& code, Color c, StateInfo* si);
+ 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(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<PieceType Pt> int count(Color c) const;
+ template<PieceType Pt> int count() const;
+ template<PieceType Pt> const Square* squares(Color c) const;
+ template<PieceType Pt> Square square(Color c) const;
+ bool is_on_semiopen_file(Color c, Square s) const;
+
+ // Castling
+ CastlingRights castling_rights(Color c) const;
+ bool can_castle(CastlingRights cr) const;
+ bool castling_impeded(CastlingRights cr) const;
+ Square castling_rook_square(CastlingRights cr) const;
+
+ // Checking
Bitboard checkers() const;
- bool is_check() const;
-
- // Piece lists
- Square piece_list(Color c, PieceType pt, int index) const;
+ Bitboard blockers_for_king(Color c) const;
+ Bitboard check_squares(PieceType pt) const;
+ Bitboard pinners(Color c) const;
+ bool is_discovery_check_on_king(Color c, Move m) 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;
- template<PieceType> Bitboard attacks_from(Square s) const;
- template<PieceType> Bitboard attacks_from(Square s, Color c) const;
+ Bitboard attackers_to(Square s, Bitboard occupied) const;
+ Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const;
// Properties of moves
- bool pl_move_is_legal(Move m) const;
- bool pl_move_is_legal(Move m, Bitboard pinned) const;
- bool move_is_check(Move m) const;
- bool move_is_check(Move m, Bitboard dcCandidates) 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;
-
- // Information about pawns
- bool pawn_is_passed(Color c, Square s) const;
- static bool pawn_is_passed(Bitboard theirPawns, Color c, Square s);
- static bool pawn_is_isolated(Bitboard ourPawns, Square s);
- static bool pawn_is_doubled(Bitboard ourPawns, Color c, Square s);
-
- // Weak squares
- bool square_is_weak(Square s, Color c) const;
+ bool legal(Move m) 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;
+ bool advanced_pawn_push(Move m) const;
+ Piece moved_piece(Move m) const;
+ Piece captured_piece() const;
+
+ // Piece specific
+ bool pawn_passed(Color c, Square s) const;
+ bool opposite_bishops() const;
+ int pawns_on_same_color_squares(Color c, Square s) const;
// Doing and undoing moves
- void saveState();
- void do_move(Move m, StateInfo& st);
- void do_move(Move m, StateInfo& st, Bitboard dcCandidates);
+ void do_move(Move m, StateInfo& newSt);
+ void do_move(Move m, StateInfo& newSt, bool givesCheck);
void undo_move(Move m);
- void do_null_move(StateInfo& st);
+ void do_null_move(StateInfo& newSt);
void undo_null_move();
- // Static exchange evaluation
- int see(Square from, Square to) const;
- int see(Move m) const;
- int see(Square to) const;
- int see_sign(Move m) const;
+ // Static Exchange Evaluation
+ bool see_ge(Move m, Value threshold = VALUE_ZERO) const;
// Accessing hash keys
- Key get_key() const;
- Key get_pawn_key() const;
- Key get_material_key() const;
-
- // Incremental evaluation
- Value mg_value() const;
- Value eg_value() const;
- Value non_pawn_material(Color c) const;
- Phase game_phase() const;
- template<GamePhase> Value pst_delta(Piece piece, Square from, Square to) const;
-
- // Game termination checks
- bool is_mate() const;
- bool is_draw() const;
-
- // Check if one side threatens a mate in one
- bool has_mate_threat(Color c);
-
- // Number of plies since the last non-reversible move
- int rule_50_counter() const;
+ Key key() const;
+ Key key_after(Move m) 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;
-
- // Reset the gamePly variable to 0
- void reset_game_ply();
+ Color side_to_move() const;
+ int game_ply() const;
+ bool is_chess960() const;
+ Thread* this_thread() const;
+ bool is_draw(int ply) const;
+ bool has_game_cycle(int ply) const;
+ bool has_repeated() const;
+ int rule50_count() const;
+ Score psq_score() const;
+ Value non_pawn_material(Color c) const;
+ Value non_pawn_material() const;
// Position consistency check, for debugging
- bool is_ok(int* failedStep = NULL) const;
+ bool pos_is_ok() const;
+ void flip();
- // Static member functions
- static void init_zobrist();
- static void init_piece_square_tables();
+ // Used by NNUE
+ StateInfo* state() const;
private:
-
- // Initialization helper functions (used while setting up a position)
- void clear();
- void put_piece(Piece p, Square s);
- void allow_oo(Color c);
- void allow_ooo(Color c);
-
- // Helper functions for doing and undoing moves
- void do_capture_move(Bitboard& 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<PieceType Piece>
- void update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates);
-
- template<bool FindPinned>
- 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
- template<GamePhase> Value pst(Color c, PieceType pt, Square s) const;
- template<GamePhase> Value compute_value() const;
- Value compute_non_pawn_material(Color c) const;
-
- // Bitboards
- Bitboard byColorBB[2], byTypeBB[8];
-
- // Board
- Piece board[64];
-
- // Piece counts
- int pieceCount[2][8]; // [color][pieceType]
-
- // Piece lists
- Square pieceList[2][8][16]; // [color][pieceType][index]
- int index[64]; // [square]
-
- // Other info
- Color sideToMove;
+ // Initialization helpers (used while setting up a position)
+ void set_castling_right(Color c, Square rfrom);
+ void set_state(StateInfo* si) const;
+ void set_check_info(StateInfo* si) const;
+
+ // Other helpers
+ void put_piece(Piece pc, Square s);
+ void remove_piece(Square s);
+ void move_piece(Square from, Square to);
+ template<bool Do>
+ 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[PIECE_NB];
+ Square pieceList[PIECE_NB][16];
+ int index[SQUARE_NB];
+ int castlingRightsMask[SQUARE_NB];
+ Square castlingRookSquare[CASTLING_RIGHT_NB];
+ Bitboard castlingPath[CASTLING_RIGHT_NB];
int gamePly;
- Key history[MaxGameLength];
- File initialKFile, initialKRFile, initialQRFile;
- StateInfo startState;
+ Color sideToMove;
+ Score psq;
+ Thread* thisThread;
StateInfo* st;
-
- // Static variables
- static int castleRightsMask[64];
- static Key zobrist[2][8][64];
- static Key zobEp[64];
- static Key zobCastle[16];
- static Key zobMaterial[2][8][16];
- static Key zobSideToMove;
- static Value MgPieceSquareTable[16][64];
- static Value EgPieceSquareTable[16][64];
+ bool chess960;
};
-
-////
-//// Inline functions
-////
-
-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));
+namespace PSQT {
+ extern Score psq[PIECE_NB][SQUARE_NB];
}
-inline bool Position::square_is_empty(Square s) const {
- return piece_on(s) == EMPTY;
-}
-
-inline bool Position::square_is_occupied(Square s) const {
- return !square_is_empty(s);
-}
-
-inline Value Position::midgame_value_of_piece_on(Square s) const {
- return piece_value_midgame(piece_on(s));
-}
-
-inline Value Position::endgame_value_of_piece_on(Square s) const {
- return piece_value_endgame(piece_on(s));
-}
+extern std::ostream& operator<<(std::ostream& os, const Position& pos);
inline Color Position::side_to_move() const {
return sideToMove;
}
-inline Bitboard Position::occupied_squares() const {
- return byTypeBB[0];
+inline Piece Position::piece_on(Square s) const {
+ assert(is_ok(s));
+ return board[s];
}
-inline Bitboard Position::empty_squares() const {
- return ~(occupied_squares());
+inline bool Position::empty(Square s) const {
+ return piece_on(s) == NO_PIECE;
}
-inline Bitboard Position::pieces_of_color(Color c) const {
- return byColorBB[c];
+inline Piece Position::moved_piece(Move m) const {
+ return piece_on(from_sq(m));
}
-inline Bitboard Position::pieces(PieceType pt) const {
+inline Bitboard Position::pieces(PieceType pt = ALL_PIECES) 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];
+ return pieces(pt1) | pieces(pt2);
}
-inline Bitboard Position::pieces(PieceType pt1, PieceType pt2, Color c) const {
- return (byTypeBB[pt1] | byTypeBB[pt2]) & byColorBB[c];
+inline Bitboard Position::pieces(Color c) const {
+ return byColorBB[c];
}
-inline int Position::piece_count(Color c, PieceType pt) const {
- return pieceCount[c][pt];
+inline Bitboard Position::pieces(Color c, PieceType pt) const {
+ return pieces(c) & pieces(pt);
}
-inline Square Position::piece_list(Color c, PieceType pt, int index) const {
- return pieceList[c][pt][index];
+inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const {
+ return pieces(c) & (pieces(pt1) | pieces(pt2));
}
-inline Square Position::ep_square() const {
- return st->epSquare;
+template<PieceType Pt> inline int Position::count(Color c) const {
+ return pieceCount[make_piece(c, Pt)];
}
-inline Square Position::king_square(Color c) const {
- return st->kingSquare[c];
+template<PieceType Pt> inline int Position::count() const {
+ return count<Pt>(WHITE) + count<Pt>(BLACK);
}
-inline bool Position::can_castle_kingside(Color side) const {
- return st->castleRights & (1+int(side));
+template<PieceType Pt> inline const Square* Position::squares(Color c) const {
+ return pieceList[make_piece(c, Pt)];
}
-inline bool Position::can_castle_queenside(Color side) const {
- return st->castleRights & (4+4*int(side));
+template<PieceType Pt> inline Square Position::square(Color c) const {
+ assert(pieceCount[make_piece(c, Pt)] == 1);
+ return squares<Pt>(c)[0];
}
-inline bool Position::can_castle(Color side) const {
- return can_castle_kingside(side) || can_castle_queenside(side);
+inline Square Position::ep_square() const {
+ return st->epSquare;
}
-inline Square Position::initial_kr_square(Color c) const {
- return relative_square(c, make_square(initialKRFile, RANK_1));
+inline bool Position::is_on_semiopen_file(Color c, Square s) const {
+ return !(pieces(c, PAWN) & file_bb(s));
}
-inline Square Position::initial_qr_square(Color c) const {
- return relative_square(c, make_square(initialQRFile, RANK_1));
+inline bool Position::can_castle(CastlingRights cr) const {
+ return st->castlingRights & cr;
}
-template<>
-inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
- return StepAttackBB[piece_of_color_and_type(c, PAWN)][s];
+inline CastlingRights Position::castling_rights(Color c) const {
+ return c & CastlingRights(st->castlingRights);
}
-template<PieceType Piece> // Knight and King and white pawns
-inline Bitboard Position::attacks_from(Square s) const {
- return StepAttackBB[Piece][s];
-}
+inline bool Position::castling_impeded(CastlingRights cr) const {
+ assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
-template<>
-inline Bitboard Position::attacks_from<BISHOP>(Square s) const {
- return bishop_attacks_bb(s, occupied_squares());
+ return pieces() & castlingPath[cr];
}
-template<>
-inline Bitboard Position::attacks_from<ROOK>(Square s) const {
- return rook_attacks_bb(s, occupied_squares());
+inline Square Position::castling_rook_square(CastlingRights cr) const {
+ assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
+
+ return castlingRookSquare[cr];
}
-template<>
-inline Bitboard Position::attacks_from<QUEEN>(Square s) const {
- return attacks_from<ROOK>(s) | attacks_from<BISHOP>(s);
+inline Bitboard Position::attackers_to(Square s) const {
+ return attackers_to(s, pieces());
}
inline Bitboard Position::checkers() const {
return st->checkersBB;
}
-inline bool Position::is_check() const {
- return st->checkersBB != EmptyBoardBB;
+inline Bitboard Position::blockers_for_king(Color c) const {
+ return st->blockersForKing[c];
}
-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::pinners(Color c) const {
+ return st->pinners[c];
}
-inline bool Position::pawn_is_passed(Bitboard theirPawns, Color c, Square s) {
- return !(theirPawns & passed_pawn_mask(c, s));
+inline Bitboard Position::check_squares(PieceType pt) const {
+ return st->checkSquares[pt];
}
-inline bool Position::pawn_is_isolated(Bitboard ourPawns, Square s) {
- return !(ourPawns & neighboring_files_bb(s));
+inline bool Position::is_discovery_check_on_king(Color c, Move m) const {
+ return st->blockersForKing[c] & from_sq(m);
}
-inline bool Position::pawn_is_doubled(Bitboard ourPawns, Color c, Square s) {
- return ourPawns & squares_behind(c, s);
+inline bool Position::pawn_passed(Color c, Square s) const {
+ return !(pieces(~c, PAWN) & passed_pawn_span(c, s));
}
-inline bool Position::square_is_weak(Square s, Color c) const {
- return !(pieces(PAWN, c) & outpost_mask(opposite_color(c), s));
+inline bool Position::advanced_pawn_push(Move m) const {
+ return type_of(moved_piece(m)) == PAWN
+ && relative_rank(sideToMove, to_sq(m)) > RANK_5;
}
-inline Key Position::get_key() const {
+inline int Position::pawns_on_same_color_squares(Color c, Square s) const {
+ return popcount(pieces(c, PAWN) & ((DarkSquares & s) ? DarkSquares : ~DarkSquares));
+}
+
+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;
}
-template<Position::GamePhase Ph>
-inline Value Position::pst(Color c, PieceType pt, Square s) const {
- return (Ph == MidGame ? MgPieceSquareTable[piece_of_color_and_type(c, pt)][s]
- : EgPieceSquareTable[piece_of_color_and_type(c, pt)][s]);
+inline Score Position::psq_score() const {
+ return psq;
}
-template<Position::GamePhase Ph>
-inline Value Position::pst_delta(Piece piece, Square from, Square to) const {
- return (Ph == MidGame ? MgPieceSquareTable[piece][to] - MgPieceSquareTable[piece][from]
- : EgPieceSquareTable[piece][to] - EgPieceSquareTable[piece][from]);
+inline Value Position::non_pawn_material(Color c) const {
+ return st->nonPawnMaterial[c];
}
-inline Value Position::mg_value() const {
- return st->mgValue;
+inline Value Position::non_pawn_material() const {
+ return non_pawn_material(WHITE) + non_pawn_material(BLACK);
}
-inline Value Position::eg_value() const {
- return st->egValue;
+inline int Position::game_ply() const {
+ return gamePly;
}
-inline Value Position::non_pawn_material(Color c) const {
- return st->npMaterial[c];
+inline int Position::rule50_count() const {
+ return st->rule50;
}
-inline Phase Position::game_phase() const {
+inline bool Position::opposite_bishops() const {
+ return count<BISHOP>(WHITE) == 1
+ && count<BISHOP>(BLACK) == 1
+ && opposite_colors(square<BISHOP>(WHITE), square<BISHOP>(BLACK));
+}
- // Values modified by Joona Kiiski
- static const Value MidgameLimit = Value(15581);
- static const Value EndgameLimit = Value(3998);
+inline bool Position::is_chess960() const {
+ return chess960;
+}
- Value npm = non_pawn_material(WHITE) + non_pawn_material(BLACK);
+inline bool Position::capture_or_promotion(Move m) const {
+ assert(is_ok(m));
+ return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m));
+}
- if (npm >= MidgameLimit)
- return PHASE_MIDGAME;
- else if(npm <= EndgameLimit)
- return PHASE_ENDGAME;
- else
- return Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit));
+inline bool Position::capture(Move m) const {
+ assert(is_ok(m));
+ // Castling is encoded as "king captures rook"
+ return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT;
}
-inline bool Position::move_is_passed_pawn_push(Move m) const {
+inline Piece Position::captured_piece() const {
+ return st->capturedPiece;
+}
- Color c = side_to_move();
- return piece_on(move_from(m)) == piece_of_color_and_type(c, PAWN)
- && pawn_is_passed(c, move_to(m));
+inline Thread* Position::this_thread() const {
+ return thisThread;
}
-inline int Position::rule_50_counter() const {
+inline void Position::put_piece(Piece pc, Square s) {
- return st->rule50;
+ board[s] = pc;
+ byTypeBB[ALL_PIECES] |= byTypeBB[type_of(pc)] |= s;
+ byColorBB[color_of(pc)] |= s;
+ index[s] = pieceCount[pc]++;
+ pieceList[pc][index[s]] = s;
+ pieceCount[make_piece(color_of(pc), ALL_PIECES)]++;
+ psq += PSQT::psq[pc][s];
}
-inline bool Position::opposite_colored_bishops() const {
+inline void Position::remove_piece(Square s) {
- return piece_count(WHITE, BISHOP) == 1
- && piece_count(BLACK, BISHOP) == 1
- && square_color(piece_list(WHITE, BISHOP, 0)) != square_color(piece_list(BLACK, BISHOP, 0));
+ // 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 invariant to a do_move() + undo_move() sequence.
+ Piece pc = board[s];
+ byTypeBB[ALL_PIECES] ^= s;
+ byTypeBB[type_of(pc)] ^= s;
+ byColorBB[color_of(pc)] ^= s;
+ /* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */
+ Square lastSquare = pieceList[pc][--pieceCount[pc]];
+ index[lastSquare] = index[s];
+ pieceList[pc][index[lastSquare]] = lastSquare;
+ pieceList[pc][pieceCount[pc]] = SQ_NONE;
+ pieceCount[make_piece(color_of(pc), ALL_PIECES)]--;
+ psq -= PSQT::psq[pc][s];
}
-inline bool Position::has_pawn_on_7th(Color c) const {
+inline void Position::move_piece(Square from, Square to) {
- return pieces(PAWN, c) & relative_rank_bb(c, RANK_7);
+ // index[from] is not updated and becomes stale. This works as long as index[]
+ // is accessed just by known occupied squares.
+ Piece pc = board[from];
+ Bitboard fromTo = from | to;
+ byTypeBB[ALL_PIECES] ^= fromTo;
+ byTypeBB[type_of(pc)] ^= fromTo;
+ byColorBB[color_of(pc)] ^= fromTo;
+ board[from] = NO_PIECE;
+ board[to] = pc;
+ index[to] = index[from];
+ pieceList[pc][index[to]] = to;
+ psq += PSQT::psq[pc][to] - PSQT::psq[pc][from];
}
-inline bool Position::move_is_capture(Move m) const {
+inline void Position::do_move(Move m, StateInfo& newSt) {
+ do_move(m, newSt, gives_check(m));
+}
- // Move must not be MOVE_NONE !
+inline StateInfo* Position::state() const {
- return (!square_is_empty(move_to(m)) && !move_is_castle(m)) || move_is_ep(m);
+ return st;
}
-#endif // !defined(POSITION_H_INCLUDED)
+#endif // #ifndef POSITION_H_INCLUDED