/// The UndoInfo struct stores information we need to restore a Position
-/// object to its previous state when we retract a move. Whenever a move
+/// object to its previous state when we retract a move. Whenever a move
/// is made on the board (by calling Position::do_move), an UndoInfo object
-/// must be passed as a parameter. When the move is unmade (by calling
+/// must be passed as a parameter. When the move is unmade (by calling
/// Position::undo_move), the same UndoInfo object must be passed again.
struct UndoInfo {
- int castleRights;
- Square epSquare;
- Bitboard checkersBB;
+ Bitboard pinners[2], pinned[2], dcCandidates[2], checkersBB;
Key key, pawnKey, materialKey;
- int rule50;
+ int castleRights, rule50;
+ Square epSquare;
Move lastMove;
Value mgValue, egValue;
PieceType capture;
+ UndoInfo* previous;
};
// Bitboards for pinned pieces and discovered check candidates
Bitboard discovered_check_candidates(Color c) const;
+ Bitboard pinned_pieces(Color c, Bitboard& p) const;
Bitboard pinned_pieces(Color c) const;
// Checking pieces
template<PieceType>
Bitboard piece_attacks_square(Square f, Square t) const; // Dispatch at compile-time
- bool piece_attacks_square(Square f, Square t) const; // Dispatch at run-time
+ bool piece_attacks_square(Piece p, Square f, Square t) const; // Dispatch at run-time
// 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_deep_pawn_push(Move m) const;
bool move_is_pawn_push_to_7th(Move m) const;
bool square_is_weak(Square s, Color c) const;
// Doing and undoing moves
- void backup(UndoInfo &u) const;
- void restore(const UndoInfo &u);
void do_move(Move m, UndoInfo &u);
- void do_move(Move m, UndoInfo &u, Bitboard dcCandidates);
- void undo_move(Move m, const UndoInfo &u);
+ void undo_move(Move m);
void do_null_move(UndoInfo &u);
void undo_null_move(const UndoInfo &u);
// Helper functions for doing and undoing moves
void do_capture_move(Move m, PieceType capture, Color them, Square to);
void do_castle_move(Move m);
- void do_promotion_move(Move m, UndoInfo &u);
+ void do_promotion_move(Move m);
void do_ep_move(Move m);
void undo_castle_move(Move m);
- void undo_promotion_move(Move m, const UndoInfo &u);
+ void undo_promotion_move(Move m);
void undo_ep_move(Move m);
void find_checkers();
void update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates);
template<PieceType Piece, bool FindPinned>
- Bitboard hidden_checks(Color c, Square ksq) const;
+ Bitboard hidden_checks(Color c, Square ksq, Bitboard& pinners) const;
// Computing hash keys from scratch (for initialization and debugging)
Key compute_key() const;
Key compute_material_key() const;
// Computing incremental evaluation scores and material counts
- Value mg_pst(Color c, PieceType pt, Square s) const;
- Value eg_pst(Color c, PieceType pt, Square s) const;
- Value compute_mg_value() const;
- Value compute_eg_value() const;
+ enum GamePhase {
+ MidGame,
+ EndGame
+ };
+ 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];
- Bitboard checkersBB;
// Board
Piece board[64];
int index[64];
// Other info
- Color sideToMove;
- int castleRights;
- File initialKFile, initialKRFile, initialQRFile;
- Square epSquare;
Square kingSquare[2];
- Move lastMove;
- Key key, pawnKey, materialKey, history[MaxGameLength];
- int rule50, gamePly;
- Value mgValue, egValue;
+ Color sideToMove;
+ int gamePly;
+ Key history[MaxGameLength];
Value npMaterial[2];
+ File initialKFile, initialKRFile, initialQRFile;
+
+ // Info backed up in do_move()
+ union {
+ UndoInfo undoInfoUnion;
+ struct { // Must have the same layout of UndoInfo
+ mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
+ Bitboard checkersBB;
+ Key key, pawnKey, materialKey;
+ int castleRights, rule50;
+ Square epSquare;
+ Move lastMove;
+ Value mgValue, egValue;
+ PieceType capture;
+ UndoInfo* previous;
+ };
+ };
// Static variables
static int castleRightsMask[64];
return materialKey;
}
-inline Value Position::mg_pst(Color c, PieceType pt, Square s) const {
- return MgPieceSquareTable[piece_of_color_and_type(c, pt)][s];
+template<Position::GamePhase Phase>
+inline Value Position::pst(Color c, PieceType pt, Square s) const {
+ return (Phase == MidGame ? MgPieceSquareTable[piece_of_color_and_type(c, pt)][s]
+ : EgPieceSquareTable[piece_of_color_and_type(c, pt)][s]);
}
inline Value Position::mg_pst_delta(Move m) const {
-MgPieceSquareTable[piece_on(move_from(m))][move_from(m)];
}
-inline Value Position::eg_pst(Color c, PieceType pt, Square s) const {
- return EgPieceSquareTable[piece_of_color_and_type(c, pt)][s];
-}
-
inline Value Position::mg_value() const {
return mgValue;
}