- template<Color Us, CastlingSide Cs, bool Checks, bool Chess960>
- ExtMove* generate_castling(const Position& pos, ExtMove* moveList) {
-
- constexpr CastlingRight Cr = Us | Cs;
- constexpr bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO);
-
- if (pos.castling_impeded(Cr) || !pos.can_castle(Cr))
- return moveList;
-
- // After castling, the rook and king final positions are the same in Chess960
- // as they would be in standard chess.
- Square kfrom = pos.square<KING>(Us);
- Square rfrom = pos.castling_rook_square(Cr);
- Square kto = relative_square(Us, KingSide ? SQ_G1 : SQ_C1);
- Bitboard enemies = pos.pieces(~Us);
-
- assert(!pos.checkers());
-
- const Direction step = Chess960 ? kto > kfrom ? WEST : EAST
- : KingSide ? WEST : EAST;
-
- for (Square s = kto; s != kfrom; s += step)
- if (pos.attackers_to(s) & enemies)
- return moveList;
-
- // Because we generate only legal castling moves we need to verify that
- // when moving the castling rook we do not discover some hidden checker.
- // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
- if (Chess960 && (attacks_bb<ROOK>(kto, pos.pieces() ^ rfrom) & pos.pieces(~Us, ROOK, QUEEN)))
- return moveList;
-
- Move m = make<CASTLING>(kfrom, rfrom);
-
- if (Checks && !pos.gives_check(m))
- return moveList;
-
- *moveList++ = m;
- return moveList;
- }
-
-