Use operator~ to flip colors and squares

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index f09d629f4e829f967558ad810f737d8fdf1d30a3..c391d8247c72f4530d78d942a1d087eb1d472180 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -392,7 +392,7 @@ 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 {