- template<CastlingSide Side, bool Checks, bool Chess960>
- ExtMove* generate_castling(const Position& pos, ExtMove* mlist, Color us) {
-
- if (pos.castling_impeded(us, Side) || !pos.can_castle(make_castling_flag(us, Side)))
- return mlist;
-
- // After castling, the rook and king final positions are the same in Chess960
- // as they would be in standard chess.
- Square kfrom = pos.king_square(us);
- Square rfrom = pos.castling_rook_square(us, Side);
- Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Bitboard enemies = pos.pieces(~us);
-
- assert(!pos.checkers());
-
- const Square K = Chess960 ? kto > kfrom ? DELTA_W : DELTA_E
- : Side == KING_SIDE ? DELTA_W : DELTA_E;
-
- for (Square s = kto; s != kfrom; s += K)
- if (pos.attackers_to(s) & enemies)
- return mlist;
-
- // 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 mlist;
-
- (mlist++)->move = make<CASTLING>(kfrom, rfrom);