Micro-optmize castling moves

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index 36d8869598292e87b158c96e4c4d4a93dc3d2690..30c25652f5b2455f966cd6767d9ae5011c43b814 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -37,6 +37,7 @@ struct CheckInfo {
   Bitboard dcCandidates;
   Bitboard pinned;
   Bitboard checkSq[8];
+  Square ksq;
 };
 
 
@@ -100,13 +101,13 @@ public:
 
   // The piece on a given square
   Piece piece_on(Square s) const;
+  Piece piece_moved(Move m) const;
   bool square_is_empty(Square s) const;
 
   // Side to move
   Color side_to_move() const;
 
   // Bitboard representation of the position
-  Bitboard empty_squares() const;
   Bitboard occupied_squares() const;
   Bitboard pieces(Color c) const;
   Bitboard pieces(PieceType pt) const;
@@ -126,6 +127,7 @@ public:
   // Castling rights
   bool can_castle(CastleRight f) const;
   bool can_castle(Color c) const;
+  bool castle_impeded(CastleRight f) const;
   Square castle_rook_square(CastleRight f) const;
 
   // Bitboards for pinned pieces and discovered check candidates
@@ -183,21 +185,14 @@ public:
   Value non_pawn_material(Color c) const;
   Score pst_delta(Piece piece, Square from, Square to) const;
 
-  // Game termination checks
-  bool is_mate() const;
+  // Other properties of the position
   template<bool SkipRepetition> bool is_draw() const;
-
-  // Plies from start position to the beginning of search
   int startpos_ply_counter() const;
-
-  // Other properties of the position
   bool opposite_colored_bishops() const;
+  bool both_color_bishops(Color c) const;
   bool has_pawn_on_7th(Color c) 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);
 
@@ -213,7 +208,7 @@ private:
   // Initialization helper functions (used while setting up a position)
   void clear();
   void put_piece(Piece p, Square s);
-  void set_castle_right(Square ksq, Square rsq);
+  void set_castle_right(Color c, Square rfrom);
   bool move_is_legal(const Move m) const;
 
   // Helper template functions
@@ -248,6 +243,7 @@ private:
   // Other info
   int castleRightsMask[64];    // [square]
   Square castleRookSquare[16]; // [castleRight]
+  Bitboard castlePath[16];     // [castleRight]
   StateInfo startState;
   int64_t nodes;
   int startPosPly;
@@ -259,7 +255,7 @@ private:
   // Static variables
   static Score pieceSquareTable[16][64]; // [piece][square]
   static Key zobrist[2][8][64];          // [color][pieceType][square]/[piece count]
-  static Key zobEp[64];                  // [square]
+  static Key zobEp[8];                   // [file]
   static Key zobCastle[16];              // [castleRight]
   static Key zobSideToMove;
   static Key zobExclusion;
@@ -277,6 +273,10 @@ inline Piece Position::piece_on(Square s) const {
   return board[s];
 }
 
+inline Piece Position::piece_moved(Move m) const {
+  return board[from_sq(m)];
+}
+
 inline bool Position::square_is_empty(Square s) const {
   return board[s] == NO_PIECE;
 }
@@ -289,10 +289,6 @@ inline Bitboard Position::occupied_squares() const {
   return occupied;
 }
 
-inline Bitboard Position::empty_squares() const {
-  return ~occupied;
-}
-
 inline Bitboard Position::pieces(Color c) const {
   return byColorBB[c];
 }
@@ -337,41 +333,32 @@ inline bool Position::can_castle(Color c) const {
   return st->castleRights & ((WHITE_OO | WHITE_OOO) << c);
 }
 
-inline Square Position::castle_rook_square(CastleRight f) const {
-  return castleRookSquare[f];
+inline bool Position::castle_impeded(CastleRight f) const {
+  return occupied & castlePath[f];
 }
 
-template<>
-inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
-  return StepAttacksBB[make_piece(c, PAWN)][s];
+inline Square Position::castle_rook_square(CastleRight f) const {
+  return castleRookSquare[f];
 }
 
-template<PieceType Piece> // Knight and King and white pawns
+template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
-  return StepAttacksBB[Piece][s];
+  return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, occupied_squares())
+        : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
+        : StepAttacksBB[Pt][s];
 }
 
 template<>
-inline Bitboard Position::attacks_from<BISHOP>(Square s) const {
-  return bishop_attacks_bb(s, occupied_squares());
-}
-
-template<>
-inline Bitboard Position::attacks_from<ROOK>(Square s) const {
-  return rook_attacks_bb(s, occupied_squares());
-}
-
-template<>
-inline Bitboard Position::attacks_from<QUEEN>(Square s) const {
-  return attacks_from<ROOK>(s) | attacks_from<BISHOP>(s);
+inline Bitboard Position::attacks_from<PAWN>(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, occupied_squares());
+  return attacks_from(p, s, occupied);
 }
 
 inline Bitboard Position::attackers_to(Square s) const {
-  return attackers_to(s, occupied_squares());
+  return attackers_to(s, occupied);
 }
 
 inline Bitboard Position::checkers() const {
@@ -391,7 +378,7 @@ inline Bitboard Position::pinned_pieces() const {
 }
 
 inline bool Position::pawn_is_passed(Color c, Square s) const {
-  return !(pieces(PAWN, flip(c)) & passed_pawn_mask(c, s));
+  return !(pieces(PAWN, ~c) & passed_pawn_mask(c, s));
 }
 
 inline Key Position::key() const {
@@ -443,6 +430,12 @@ inline bool Position::opposite_colored_bishops() const {
         && opposite_colors(pieceList[WHITE][BISHOP][0], pieceList[BLACK][BISHOP][0]);
 }
 
+inline bool Position::both_color_bishops(Color c) const {
+  // Assumes that there are only two bishops
+  return  pieceCount[c][BISHOP] >= 2 &&
+          opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]);
+}
+
 inline bool Position::has_pawn_on_7th(Color c) const {
   return pieces(PAWN, c) & rank_bb(relative_rank(c, RANK_7));
 }