- if(piece == king_of_color(us)) {
- // Is this a castling move? A king move is assumed to be a castling
- // move if the destination square is occupied by a friendly rook, or
- // if the distance between the source and destination squares is more
- // than 1.
- if(pos.piece_on(to) == rook_of_color(us))
- return make_castle_move(from, to);
- else if(square_distance(from, to) > 1) {
- // This is a castling move, but we have to translate it to the
- // internal "king captures rook" representation.
- SquareDelta delta = (to > from)? DELTA_E : DELTA_W;
- Square s;
- for(s = from + delta;
- relative_rank(us, s) == RANK_1 && pos.piece_on(s) != rook_of_color(us);
- s += delta);
- if(relative_rank(us, s) == RANK_1 && pos.piece_on(s) == rook_of_color(us))
- return make_castle_move(from, s);
- }
+ if (piece == piece_of_color_and_type(us, KING))
+ {
+ // Is this a castling move? A king move is assumed to be a castling
+ // move if the destination square is occupied by a friendly rook, or
+ // if the distance between the source and destination squares is more
+ // than 1.
+ if (pos.piece_on(to) == piece_of_color_and_type(us, ROOK))
+ return make_castle_move(from, to);
+
+ else if (square_distance(from, to) > 1)
+ {
+ // This is a castling move, but we have to translate it to the
+ // internal "king captures rook" representation.
+ SquareDelta delta = (to > from ? DELTA_E : DELTA_W);
+ Square s = from + delta;
+ while (relative_rank(us, s) == RANK_1 && pos.piece_on(s) != piece_of_color_and_type(us, ROOK))
+ s += delta;
+
+ return (relative_rank(us, s) == RANK_1 ? make_castle_move(from, s) : MOVE_NONE);
+ }