X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fbitboard.h;h=f1db634f1bd058910ef32127bb9f6f956437dd9b;hb=a8e903c33a676decfcf5c721b6b4bfdb4102e5c0;hp=559c70f62acf9e5f056d26f205fa6dc2aa24f38f;hpb=cf5d683408a2ef8a1c80be9bf7d6790a38b16277;p=stockfish

diff --git a/src/bitboard.h b/src/bitboard.h
index 559c70f6..f1db634f 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -135,6 +135,11 @@ constexpr bool more_than_one(Bitboard b) {
   return b & (b - 1);
 }
 
+inline bool opposite_colors(Square s1, Square s2) {
+
+  return bool(DarkSquares & s1) != bool(DarkSquares & s2);
+}
+
 /// rank_bb() and file_bb() return a bitboard representing all the squares on
 /// the given file or rank.
 
@@ -177,6 +182,16 @@ constexpr Bitboard pawn_attacks_bb(Bitboard b) {
 }
 
 
+/// double_pawn_attacks_bb() returns the pawn attacks for the given color
+/// from the squares in the given bitboard.
+
+template<Color C>
+constexpr Bitboard double_pawn_attacks_bb(Bitboard b) {
+  return C == WHITE ? shift<NORTH_WEST>(b) & shift<NORTH_EAST>(b)
+                    : shift<SOUTH_WEST>(b) & shift<SOUTH_EAST>(b);
+}
+
+
 /// adjacent_files_bb() returns a bitboard representing all the squares on the
 /// adjacent files of the given one.