Detect stalemate in KXK endgames

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index f09d629f4e829f967558ad810f737d8fdf1d30a3..8229e71b4a1a4e8c3c66f7cdcd12cbaa580635b2 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -189,6 +189,7 @@ public:
   template<bool SkipRepetition> bool is_draw() const;
   int startpos_ply_counter() const;
   bool opposite_colored_bishops() const;
+  bool both_color_bishops(Color c) const;
   bool has_pawn_on_7th(Color c) const;
   bool is_chess960() const;
 
@@ -342,29 +343,17 @@ inline Square Position::castle_rook_square(CastleRight f) const {
   return castleRookSquare[f];
 }
 
-template<>
-inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
-  return StepAttacksBB[make_piece(c, PAWN)][s];
-}
-
-template<PieceType Piece> // Knight and King and white pawns
+template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
-  return StepAttacksBB[Piece][s];
-}
-
-template<>
-inline Bitboard Position::attacks_from<BISHOP>(Square s) const {
-  return bishop_attacks_bb(s, occupied_squares());
+  return  Pt == BISHOP ? bishop_attacks_bb(s, occupied_squares())
+        : Pt == ROOK   ? rook_attacks_bb(s, occupied_squares())
+        : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
+                       : StepAttacksBB[Pt][s];
 }
 
 template<>
-inline Bitboard Position::attacks_from<ROOK>(Square s) const {
-  return rook_attacks_bb(s, occupied_squares());
-}
-
-template<>
-inline Bitboard Position::attacks_from<QUEEN>(Square s) const {
-  return attacks_from<ROOK>(s) | attacks_from<BISHOP>(s);
+inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
+  return StepAttacksBB[make_piece(c, PAWN)][s];
 }
 
 inline Bitboard Position::attacks_from(Piece p, Square s) const {
@@ -392,7 +381,7 @@ 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 {
@@ -444,6 +433,12 @@ inline bool Position::opposite_colored_bishops() const {
         && opposite_colors(pieceList[WHITE][BISHOP][0], pieceList[BLACK][BISHOP][0]);
 }
 
+inline bool Position::both_color_bishops(Color c) const {
+  // Assumes that there are only two bishops
+  return  pieceCount[c][BISHOP] >= 2 &&
+          opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]);
+}
+
 inline bool Position::has_pawn_on_7th(Color c) const {
   return pieces(PAWN, c) & rank_bb(relative_rank(c, RANK_7));
 }