Micro-optmize castling moves

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index 8229e71b4a1a4e8c3c66f7cdcd12cbaa580635b2..30c25652f5b2455f966cd6767d9ae5011c43b814 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -108,7 +108,6 @@ public:
   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;
@@ -128,6 +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
@@ -192,10 +192,7 @@ public:
   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);
 
@@ -211,7 +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(Color c, Square rsq);
+  void set_castle_right(Color c, Square rfrom);
   bool move_is_legal(const Move m) const;
 
   // Helper template functions
@@ -246,6 +243,7 @@ private:
   // Other info
   int castleRightsMask[64];    // [square]
   Square castleRookSquare[16]; // [castleRight]
+  Bitboard castlePath[16];     // [castleRight]
   StateInfo startState;
   int64_t nodes;
   int startPosPly;
@@ -257,7 +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;
@@ -291,10 +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];
 }
@@ -339,16 +333,19 @@ inline bool Position::can_castle(Color c) const {
   return st->castleRights & ((WHITE_OO | WHITE_OOO) << c);
 }
 
+inline bool Position::castle_impeded(CastleRight f) const {
+  return occupied & castlePath[f];
+}
+
 inline Square Position::castle_rook_square(CastleRight f) const {
   return castleRookSquare[f];
 }
 
 template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
-  return  Pt == BISHOP ? bishop_attacks_bb(s, occupied_squares())
-        : Pt == ROOK   ? rook_attacks_bb(s, occupied_squares())
+  return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, occupied_squares())
         : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
-                       : StepAttacksBB[Pt][s];
+        : StepAttacksBB[Pt][s];
 }
 
 template<>
@@ -357,11 +354,11 @@ inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
 }
 
 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 {