Micro-optimize do_castle_move()

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 60c5380d8352e329c2b662e218d75fbb885717cc..9af42558867b52aeec7c5e525dbb8c21ed2407ee 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -240,7 +240,7 @@ void Position::set_castle_right(Color c, Square rfrom) {
 
   Square kfrom = king_square(c);
   CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE;
-  int cr = (cs == KING_SIDE ? WHITE_OO : WHITE_OOO) << c;
+  CastleRight cr = make_castle_right(c, cs);
 
   st->castleRights |= cr;
   castleRightsMask[kfrom] |= cr;
@@ -830,7 +830,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
   prefetch((char*)TT.first_entry(k));
 
   // Move the piece
-  Bitboard from_to_bb = SquareBB[from] | SquareBB[to];
+  Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
   byTypeBB[ALL_PIECES] ^= from_to_bb;
   byTypeBB[pt] ^= from_to_bb;
   byColorBB[us] ^= from_to_bb;
@@ -995,7 +995,7 @@ void Position::undo_move(Move m) {
   }
 
   // Put the piece back at the source square
-  Bitboard from_to_bb = SquareBB[from] | SquareBB[to];
+  Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
   byTypeBB[ALL_PIECES] ^= from_to_bb;
   byTypeBB[pt] ^= from_to_bb;
   byColorBB[us] ^= from_to_bb;
@@ -1078,21 +1078,13 @@ void Position::do_castle_move(Move m) {
   assert(piece_on(kfrom) == make_piece(us, KING));
   assert(piece_on(rfrom) == make_piece(us, ROOK));
 
-  // Remove pieces from source squares
-  byTypeBB[ALL_PIECES] ^= kfrom;
-  byTypeBB[KING] ^= kfrom;
-  byColorBB[us] ^= kfrom;
-  byTypeBB[ALL_PIECES] ^= rfrom;
-  byTypeBB[ROOK] ^= rfrom;
-  byColorBB[us] ^= rfrom;
-
-  // Put pieces on destination squares
-  byTypeBB[ALL_PIECES] |= kto;
-  byTypeBB[KING] |= kto;
-  byColorBB[us] |= kto;
-  byTypeBB[ALL_PIECES] |= rto;
-  byTypeBB[ROOK] |= rto;
-  byColorBB[us] |= rto;
+  // Move the pieces, with some care; in chess960 could be kto == rfrom
+  Bitboard k_from_to_bb = SquareBB[kfrom] ^ SquareBB[kto];
+  Bitboard r_from_to_bb = SquareBB[rfrom] ^ SquareBB[rto];
+  byTypeBB[KING] ^= k_from_to_bb;
+  byTypeBB[ROOK] ^= r_from_to_bb;
+  byTypeBB[ALL_PIECES] ^= k_from_to_bb ^ r_from_to_bb;
+  byColorBB[us] ^= k_from_to_bb ^ r_from_to_bb;
 
   // Update board
   Piece king = make_piece(us, KING);
@@ -1727,15 +1719,13 @@ bool Position::pos_is_ok(int* failedStep) const {
   if (failedStep) (*failedStep)++;
   if (debugCastleSquares)
       for (Color c = WHITE; c <= BLACK; c++)
-          for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s+1))
+          for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1))
           {
-              CastleRight cr = CastleRight((s == KING_SIDE ? WHITE_OO : WHITE_OOO) << c);
-
-              if (!can_castle(cr))
+              if (!can_castle(make_castle_right(c, s)))
                   continue;
 
               if (   piece_on(castleRookSquare[c][s]) != make_piece(c, ROOK)
-                  || castleRightsMask[castleRookSquare[c][s]] != cr)
+                  || castleRightsMask[castleRookSquare[c][s]] != make_castle_right(c, s))
                   return false;
           }