Add behind_bb() helper to simplify code logic

[stockfish] / src / bitboard.h

diff --git a/src/bitboard.h b/src/bitboard.h
index b193786cb8e28eae2096cbcb9095b14dd006cf5c..847132c499fdc41df9cddf97e44f01c90dd4bb7f 100644 (file)
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -236,6 +236,19 @@ inline Bitboard in_front_bb(Color c, Square s) {
 }
 
 
+/// behind_bb() takes a color and a rank or square as input, and returns a
+/// bitboard representing all the squares on all ranks behind of the rank
+/// (or square), from the given color's point of view.
+
+inline Bitboard behind_bb(Color c, Rank r) {
+  return InFrontBB[opposite_color(c)][r];
+}
+
+inline Bitboard behind_bb(Color c, Square s) {
+  return in_front_bb(opposite_color(c), square_rank(s));
+}
+
+
 /// ray_bb() gives a bitboard representing all squares along the ray in a
 /// given direction from a given square.