Equations for edges and corners.

[stockfish] / src / bitboard.h

diff --git a/src/bitboard.h b/src/bitboard.h
index 3ea18dd88d6f09bb31c9a0f9813b8a6c44f24214..f1d14603687fd19ae0d975799154d15ac8058a66 100644 (file)
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -255,6 +255,8 @@ template<> inline int distance<File>(Square x, Square y) { return std::abs(file_
 template<> inline int distance<Rank>(Square x, Square y) { return std::abs(rank_of(x) - rank_of(y)); }
 template<> inline int distance<Square>(Square x, Square y) { return SquareDistance[x][y]; }
 
+inline File edge_distance(File f) { return std::min(f, File(FILE_H - f)); }
+inline Rank edge_distance(Rank r) { return std::min(r, Rank(RANK_8 - r)); }
 
 /// attacks_bb() returns a bitboard representing all the squares attacked by a
 /// piece of type Pt (bishop or rook) placed on 's'.