Micro optimize copy of new state in do_move()

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index aaed663b79209620a490d276bc6b86a34c879d2f..8e29eb13458390ff2d4a405ffd61cebd794f46ee 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -73,20 +73,21 @@ enum CastleRights {
 };
 
 
-/// The UndoInfo struct stores information we need to restore a Position
+/// 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 UndoInfo object
-/// must be passed as a parameter. When the move is unmade (by calling
-/// Position::undo_move), the same UndoInfo object must be passed again.
+/// is made on the board (by calling Position::do_move), an StateInfo object
+/// must be passed as a parameter.
 
-struct UndoInfo {
-  Bitboard pinners[2], pinned[2], dcCandidates[2], checkersBB;
+struct StateInfo {
   Key key, pawnKey, materialKey;
   int castleRights, rule50;
   Square epSquare;
-  Move lastMove;
   Value mgValue, egValue;
+
   PieceType capture;
+  Bitboard checkersBB;
+  Move lastMove;
+  StateInfo* previous;
 };
 
 
@@ -219,7 +220,9 @@ public:
 
   // 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;
@@ -240,10 +243,12 @@ public:
   bool square_is_weak(Square s, Color c) const;
 
   // Doing and undoing moves
-  void do_move(Move m, UndoInfo &u);
-  void undo_move(Move m, const UndoInfo &u);
-  void do_null_move(UndoInfo &u);
-  void undo_null_move(const UndoInfo &u);
+  void setStartState(const StateInfo& st);
+  void do_move(Move m, StateInfo& st);
+  void do_move(Move m, StateInfo& st, Bitboard dcCandidates);
+  void undo_move(Move m);
+  void do_null_move(StateInfo& st);
+  void undo_null_move();
 
   // Static exchange evaluation
   int see(Square from, Square to) const;
@@ -287,6 +292,7 @@ public:
   static void init_piece_square_tables();
 
 private:
+
   // Initialization helper functions (used while setting up a position)
   void clear();
   void put_piece(Piece p, Square s);
@@ -296,10 +302,10 @@ private:
   // 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();
 
@@ -315,10 +321,12 @@ private:
   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
@@ -341,21 +349,8 @@ private:
   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;
-      };
-  };
+  StateInfo startState;
+  StateInfo* st;
 
   // Static variables
   static int castleRightsMask[64];
@@ -506,7 +501,7 @@ inline Square Position::piece_list(Color c, PieceType pt, int index) const {
 }
 
 inline Square Position::ep_square() const {
-  return epSquare;
+  return st->epSquare;
 }
 
 inline Square Position::king_square(Color c) const {
@@ -514,11 +509,11 @@ inline Square Position::king_square(Color c) const {
 }
 
 inline bool Position::can_castle_kingside(Color side) const {
-  return castleRights & (1+int(side));
+  return st->castleRights & (1+int(side));
 }
 
 inline bool Position::can_castle_queenside(Color side) const {
-  return castleRights & (4+4*int(side));
+  return st->castleRights & (4+4*int(side));
 }
 
 inline bool Position::can_castle(Color side) const {
@@ -568,11 +563,11 @@ inline Bitboard Position::piece_attacks<KING>(Square s) const {
 }
 
 inline Bitboard Position::checkers() const {
-  return checkersBB;
+  return st->checkersBB;
 }
 
 inline bool Position::is_check() const {
-  return checkersBB != EmptyBoardBB;
+  return st->checkersBB != EmptyBoardBB;
 }
 
 inline bool Position::pawn_attacks_square(Color c, Square f, Square t) const {
@@ -619,19 +614,21 @@ inline bool Position::square_is_weak(Square s, Color c) const {
 }
 
 inline Key Position::get_key() const {
-  return key;
+  return st->key;
 }
 
 inline Key Position::get_pawn_key() const {
-  return pawnKey;
+  return st->pawnKey;
 }
 
 inline Key Position::get_material_key() const {
-  return materialKey;
+  return st->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 {
@@ -639,16 +636,12 @@ 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;
+  return st->mgValue;
 }
 
 inline Value Position::eg_value() const {
-  return egValue;
+  return st->egValue;
 }
 
 inline Value Position::non_pawn_material(Color c) const {
@@ -707,7 +700,7 @@ inline bool Position::move_was_passed_pawn_push(Move m) const {
 
 inline int Position::rule_50_counter() const {
 
-  return rule50;
+  return st->rule50;
 }
 
 inline bool Position::opposite_colored_bishops() const {