/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
+ Copyright (C) 2004-2023 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
#include <cassert>
#include <deque>
-#include <memory> // For std::unique_ptr
+#include <iosfwd>
+#include <memory>
#include <string>
#include "bitboard.h"
-#include "evaluate.h"
-#include "psqt.h"
-#include "types.h"
-
#include "nnue/nnue_accumulator.h"
+#include "types.h"
namespace Stockfish {
-/// 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.
+// 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 {
- // 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;
- StateInfo* previous;
- Bitboard blockersForKing[COLOR_NB];
- Bitboard pinners[COLOR_NB];
- Bitboard checkSquares[PIECE_TYPE_NB];
- Piece capturedPiece;
- int repetition;
-
- // Used by NNUE
- Eval::NNUE::Accumulator accumulator;
- DirtyPiece dirtyPiece;
+ // Copied when making a move
+ Key materialKey;
+ Key pawnKey;
+ 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;
+ StateInfo* previous;
+ Bitboard blockersForKing[COLOR_NB];
+ Bitboard pinners[COLOR_NB];
+ Bitboard checkSquares[PIECE_TYPE_NB];
+ Piece capturedPiece;
+ int repetition;
+
+ // Used by NNUE
+ Eval::NNUE::Accumulator accumulator;
+ DirtyPiece dirtyPiece;
};
-/// 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;
+// 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.
+using StateListPtr = std::unique_ptr<std::deque<StateInfo>>;
-/// 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 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();
-
- Position() = default;
- Position(const Position&) = delete;
- Position& operator=(const Position&) = delete;
-
- // 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);
- std::string fen() const;
-
- // Position representation
- Bitboard pieces(PieceType pt) const;
- Bitboard pieces(PieceType pt1, PieceType pt2) const;
- 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;
- bool empty(Square s) const;
- template<PieceType Pt> int count(Color c) const;
- template<PieceType Pt> int count() 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;
- Bitboard blockers_for_king(Color c) const;
- Bitboard check_squares(PieceType pt) const;
- Bitboard pinners(Color c) const;
-
- // Attacks to/from a given square
- Bitboard attackers_to(Square s) const;
- Bitboard attackers_to(Square s, Bitboard occupied) const;
- Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const;
-
- // Properties of moves
- 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;
- 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 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& newSt);
- void undo_null_move();
-
- // Static Exchange Evaluation
- bool see_ge(Move m, Value threshold = VALUE_ZERO) const;
-
- // Accessing hash keys
- Key key() const;
- Key key_after(Move m) const;
- Key material_key() const;
- Key pawn_key() const;
-
- // Other properties of the position
- 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 pos_is_ok() const;
- void flip();
-
- // Used by NNUE
- StateInfo* state() const;
-
- void put_piece(Piece pc, Square s);
- void remove_piece(Square s);
-
-private:
- // 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 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];
- int castlingRightsMask[SQUARE_NB];
- Square castlingRookSquare[CASTLING_RIGHT_NB];
- Bitboard castlingPath[CASTLING_RIGHT_NB];
- Thread* thisThread;
- StateInfo* st;
- int gamePly;
- Color sideToMove;
- Score psq;
- bool chess960;
+ public:
+ static void init();
+
+ Position() = default;
+ Position(const Position&) = delete;
+ Position& operator=(const Position&) = delete;
+
+ // 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);
+ std::string fen() const;
+
+ // Position representation
+ Bitboard pieces(PieceType pt = ALL_PIECES) const;
+ template<typename... PieceTypes>
+ Bitboard pieces(PieceType pt, PieceTypes... pts) const;
+ Bitboard pieces(Color c) const;
+ template<typename... PieceTypes>
+ Bitboard pieces(Color c, PieceTypes... pts) const;
+ Piece piece_on(Square s) const;
+ Square ep_square() const;
+ bool empty(Square s) const;
+ template<PieceType Pt>
+ int count(Color c) const;
+ template<PieceType Pt>
+ int count() const;
+ template<PieceType Pt>
+ Square square(Color c) 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;
+ Bitboard blockers_for_king(Color c) const;
+ Bitboard check_squares(PieceType pt) const;
+ Bitboard pinners(Color c) const;
+
+ // Attacks to/from a given square
+ Bitboard attackers_to(Square s) const;
+ Bitboard attackers_to(Square s, Bitboard occupied) const;
+ void update_slider_blockers(Color c) const;
+ template<PieceType Pt>
+ Bitboard attacks_by(Color c) const;
+
+ // Properties of moves
+ bool legal(Move m) const;
+ bool pseudo_legal(const Move m) const;
+ bool capture(Move m) const;
+ bool capture_stage(Move m) const;
+ bool gives_check(Move m) const;
+ Piece moved_piece(Move m) const;
+ Piece captured_piece() const;
+
+ // Doing and undoing moves
+ 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& newSt);
+ void undo_null_move();
+
+ // Static Exchange Evaluation
+ bool see_ge(Move m, Value threshold = VALUE_ZERO) const;
+
+ // Accessing hash keys
+ Key key() const;
+ Key key_after(Move m) const;
+ Key material_key() const;
+ Key pawn_key() const;
+
+ // Other properties of the position
+ 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;
+ Value non_pawn_material(Color c) const;
+ Value non_pawn_material() const;
+
+ // Position consistency check, for debugging
+ bool pos_is_ok() const;
+ void flip();
+
+ // Used by NNUE
+ StateInfo* state() const;
+
+ void put_piece(Piece pc, Square s);
+ void remove_piece(Square s);
+
+ private:
+ // Initialization helpers (used while setting up a position)
+ void set_castling_right(Color c, Square rfrom);
+ void set_state() const;
+ void set_check_info() const;
+
+ // Other helpers
+ void move_piece(Square from, Square to);
+ template<bool Do>
+ void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto);
+ template<bool AfterMove>
+ Key adjust_key50(Key k) const;
+
+ // Data members
+ Piece board[SQUARE_NB];
+ Bitboard byTypeBB[PIECE_TYPE_NB];
+ Bitboard byColorBB[COLOR_NB];
+ int pieceCount[PIECE_NB];
+ int castlingRightsMask[SQUARE_NB];
+ Square castlingRookSquare[CASTLING_RIGHT_NB];
+ Bitboard castlingPath[CASTLING_RIGHT_NB];
+ Thread* thisThread;
+ StateInfo* st;
+ int gamePly;
+ Color sideToMove;
+ bool chess960;
};
-extern std::ostream& operator<<(std::ostream& os, const Position& pos);
+std::ostream& operator<<(std::ostream& os, const Position& pos);
-inline Color Position::side_to_move() const {
- return sideToMove;
-}
+inline Color Position::side_to_move() const { return sideToMove; }
inline Piece Position::piece_on(Square s) const {
- assert(is_ok(s));
- return board[s];
+ assert(is_ok(s));
+ return board[s];
}
-inline bool Position::empty(Square s) const {
- return piece_on(s) == NO_PIECE;
-}
+inline bool Position::empty(Square s) const { return piece_on(s) == NO_PIECE; }
-inline Piece Position::moved_piece(Move m) const {
- return piece_on(from_sq(m));
-}
+inline Piece Position::moved_piece(Move m) const { return piece_on(from_sq(m)); }
-inline Bitboard Position::pieces(PieceType pt = ALL_PIECES) const {
- return byTypeBB[pt];
-}
+inline Bitboard Position::pieces(PieceType pt) const { return byTypeBB[pt]; }
-inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const {
- return pieces(pt1) | pieces(pt2);
+template<typename... PieceTypes>
+inline Bitboard Position::pieces(PieceType pt, PieceTypes... pts) const {
+ return pieces(pt) | pieces(pts...);
}
-inline Bitboard Position::pieces(Color c) const {
- return byColorBB[c];
-}
+inline Bitboard Position::pieces(Color c) const { return byColorBB[c]; }
-inline Bitboard Position::pieces(Color c, PieceType pt) const {
- return pieces(c) & pieces(pt);
+template<typename... PieceTypes>
+inline Bitboard Position::pieces(Color c, PieceTypes... pts) const {
+ return pieces(c) & pieces(pts...);
}
-inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const {
- return pieces(c) & (pieces(pt1) | pieces(pt2));
+template<PieceType Pt>
+inline int Position::count(Color c) const {
+ return pieceCount[make_piece(c, Pt)];
}
-template<PieceType Pt> inline int Position::count(Color c) const {
- return pieceCount[make_piece(c, Pt)];
+template<PieceType Pt>
+inline int Position::count() const {
+ return count<Pt>(WHITE) + count<Pt>(BLACK);
}
-template<PieceType Pt> inline int Position::count() const {
- return count<Pt>(WHITE) + count<Pt>(BLACK);
+template<PieceType Pt>
+inline Square Position::square(Color c) const {
+ assert(count<Pt>(c) == 1);
+ return lsb(pieces(c, Pt));
}
-template<PieceType Pt> inline Square Position::square(Color c) const {
- assert(count<Pt>(c) == 1);
- return lsb(pieces(c, Pt));
-}
+inline Square Position::ep_square() const { return st->epSquare; }
-inline Square Position::ep_square() const {
- return st->epSquare;
-}
-
-inline bool Position::is_on_semiopen_file(Color c, Square s) const {
- return !(pieces(c, PAWN) & file_bb(s));
-}
-
-inline bool Position::can_castle(CastlingRights cr) const {
- return st->castlingRights & cr;
-}
+inline bool Position::can_castle(CastlingRights cr) const { return st->castlingRights & cr; }
inline CastlingRights Position::castling_rights(Color c) const {
- return c & CastlingRights(st->castlingRights);
+ return c & CastlingRights(st->castlingRights);
}
inline bool Position::castling_impeded(CastlingRights cr) const {
- assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
+ assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
- return pieces() & castlingPath[cr];
+ return pieces() & castlingPath[cr];
}
inline Square Position::castling_rook_square(CastlingRights cr) const {
- assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
+ assert(cr == WHITE_OO || cr == WHITE_OOO || cr == BLACK_OO || cr == BLACK_OOO);
- return castlingRookSquare[cr];
+ return castlingRookSquare[cr];
}
-inline Bitboard Position::attackers_to(Square s) const {
- return attackers_to(s, pieces());
-}
+inline Bitboard Position::attackers_to(Square s) const { return attackers_to(s, pieces()); }
-inline Bitboard Position::checkers() const {
- return st->checkersBB;
-}
+template<PieceType Pt>
+inline Bitboard Position::attacks_by(Color c) const {
-inline Bitboard Position::blockers_for_king(Color c) const {
- return st->blockersForKing[c];
+ if constexpr (Pt == PAWN)
+ return c == WHITE ? pawn_attacks_bb<WHITE>(pieces(WHITE, PAWN))
+ : pawn_attacks_bb<BLACK>(pieces(BLACK, PAWN));
+ else
+ {
+ Bitboard threats = 0;
+ Bitboard attackers = pieces(c, Pt);
+ while (attackers)
+ threats |= attacks_bb<Pt>(pop_lsb(attackers), pieces());
+ return threats;
+ }
}
-inline Bitboard Position::pinners(Color c) const {
- return st->pinners[c];
-}
+inline Bitboard Position::checkers() const { return st->checkersBB; }
-inline Bitboard Position::check_squares(PieceType pt) const {
- return st->checkSquares[pt];
-}
+inline Bitboard Position::blockers_for_king(Color c) const { return st->blockersForKing[c]; }
-inline bool Position::pawn_passed(Color c, Square s) const {
- return !(pieces(~c, PAWN) & passed_pawn_span(c, s));
-}
+inline Bitboard Position::pinners(Color c) const { return st->pinners[c]; }
-inline int Position::pawns_on_same_color_squares(Color c, Square s) const {
- return popcount(pieces(c, PAWN) & ((DarkSquares & s) ? DarkSquares : ~DarkSquares));
-}
+inline Bitboard Position::check_squares(PieceType pt) const { return st->checkSquares[pt]; }
-inline Key Position::key() const {
- return st->rule50 < 14 ? st->key
- : st->key ^ make_key((st->rule50 - 14) / 8);
-}
+inline Key Position::key() const { return adjust_key50<false>(st->key); }
-inline Key Position::pawn_key() const {
- return st->pawnKey;
+template<bool AfterMove>
+inline Key Position::adjust_key50(Key k) const {
+ return st->rule50 < 14 - AfterMove ? k : k ^ make_key((st->rule50 - (14 - AfterMove)) / 8);
}
-inline Key Position::material_key() const {
- return st->materialKey;
-}
+inline Key Position::pawn_key() const { return st->pawnKey; }
-inline Score Position::psq_score() const {
- return psq;
-}
+inline Key Position::material_key() const { return st->materialKey; }
-inline Value Position::non_pawn_material(Color c) const {
- return st->nonPawnMaterial[c];
-}
+inline Value Position::non_pawn_material(Color c) const { return st->nonPawnMaterial[c]; }
inline Value Position::non_pawn_material() const {
- return non_pawn_material(WHITE) + non_pawn_material(BLACK);
+ return non_pawn_material(WHITE) + non_pawn_material(BLACK);
}
-inline int Position::game_ply() const {
- return gamePly;
-}
+inline int Position::game_ply() const { return gamePly; }
-inline int Position::rule50_count() const {
- return st->rule50;
-}
+inline int Position::rule50_count() const { return st->rule50; }
-inline bool Position::opposite_bishops() const {
- return count<BISHOP>(WHITE) == 1
- && count<BISHOP>(BLACK) == 1
- && opposite_colors(square<BISHOP>(WHITE), square<BISHOP>(BLACK));
-}
-
-inline bool Position::is_chess960() const {
- return chess960;
-}
+inline bool Position::is_chess960() const { return chess960; }
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) == EN_PASSANT;
+ assert(is_ok(m));
+ return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == EN_PASSANT;
}
-inline Piece Position::captured_piece() const {
- return st->capturedPiece;
+// Returns true if a move is generated from the capture stage, having also
+// queen promotions covered, i.e. consistency with the capture stage move generation
+// is needed to avoid the generation of duplicate moves.
+inline bool Position::capture_stage(Move m) const {
+ assert(is_ok(m));
+ return capture(m) || promotion_type(m) == QUEEN;
}
-inline Thread* Position::this_thread() const {
- return thisThread;
-}
+inline Piece Position::captured_piece() const { return st->capturedPiece; }
+
+inline Thread* Position::this_thread() const { return thisThread; }
inline void Position::put_piece(Piece pc, Square s) {
- board[s] = pc;
- byTypeBB[ALL_PIECES] |= byTypeBB[type_of(pc)] |= s;
- byColorBB[color_of(pc)] |= s;
- pieceCount[pc]++;
- pieceCount[make_piece(color_of(pc), ALL_PIECES)]++;
- psq += PSQT::psq[pc][s];
+ board[s] = pc;
+ byTypeBB[ALL_PIECES] |= byTypeBB[type_of(pc)] |= s;
+ byColorBB[color_of(pc)] |= s;
+ pieceCount[pc]++;
+ pieceCount[make_piece(color_of(pc), ALL_PIECES)]++;
}
inline void Position::remove_piece(Square s) {
- Piece pc = board[s];
- byTypeBB[ALL_PIECES] ^= s;
- byTypeBB[type_of(pc)] ^= s;
- byColorBB[color_of(pc)] ^= s;
- board[s] = NO_PIECE;
- pieceCount[pc]--;
- pieceCount[make_piece(color_of(pc), ALL_PIECES)]--;
- psq -= PSQT::psq[pc][s];
+ Piece pc = board[s];
+ byTypeBB[ALL_PIECES] ^= s;
+ byTypeBB[type_of(pc)] ^= s;
+ byColorBB[color_of(pc)] ^= s;
+ board[s] = NO_PIECE;
+ pieceCount[pc]--;
+ pieceCount[make_piece(color_of(pc), ALL_PIECES)]--;
}
inline void Position::move_piece(Square from, Square to) {
- 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;
- psq += PSQT::psq[pc][to] - PSQT::psq[pc][from];
-}
-
-inline void Position::do_move(Move m, StateInfo& newSt) {
- do_move(m, newSt, gives_check(m));
+ 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;
}
-inline StateInfo* Position::state() const {
+inline void Position::do_move(Move m, StateInfo& newSt) { do_move(m, newSt, gives_check(m)); }
- return st;
-}
+inline StateInfo* Position::state() const { return st; }
-} // namespace Stockfish
+} // namespace Stockfish
-#endif // #ifndef POSITION_H_INCLUDED
+#endif // #ifndef POSITION_H_INCLUDED
projects / stockfish / blobdiff