}
-/// Position:hidden_checkers() returns a bitboard of all pinned / discovered check
-/// pieces, according to the call parameters. Pinned pieces protect our king and
-/// discovered check pieces attack the enemy king.
-
-Bitboard Position::hidden_checkers(Color c, Color kingColor) const {
+/// Position::check_blockers() returns a bitboard of all the pieces with color
+/// 'c' that are blocking check on the king with color 'kingColor'. A piece
+/// blocks a check if removing that piece from the board would result in a
+/// position where the king is in check. A check blocking piece can be either a
+/// pinned or a discovered check piece, according if its color 'c' is the same
+/// or the opposite of 'kingColor'.
+
+Bitboard Position::check_blockers(Color c, Color kingColor) const {
Bitboard b, pinners, result = 0;
Square ksq = king_square(kingColor);
// Helper functions
void do_castling(Square kfrom, Square kto, Square rfrom, Square rto);
- Bitboard hidden_checkers(Color c, Color kingColor) const;
+ Bitboard check_blockers(Color c, Color kingColor) const;
void put_piece(Square s, Color c, PieceType pt);
void remove_piece(Square s, Color c, PieceType pt);
void move_piece(Square from, Square to, Color c, PieceType pt);
}
inline Bitboard Position::discovered_check_candidates() const {
- return hidden_checkers(sideToMove, ~sideToMove);
+ return check_blockers(sideToMove, ~sideToMove);
}
inline Bitboard Position::pinned_pieces(Color c) const {
- return hidden_checkers(c, c);
+ return check_blockers(c, c);
}
inline bool Position::pawn_passed(Color c, Square s) const {