bit_ff_area_at_
*(_resultp) = bit_ff_area_at_(_bitstr, _start, _nbits, _size, _match);
*(_resultp) = bit_ff_area_at_((_bitstr), (_start), (_nbits), (_size), 1)
*(_resultp) = bit_ff_area_at_((_bitstr), (_start), (_nbits), (_size), 0)
*(_resultp) = bit_ff_area_at_((_bitstr), 0, (_nbits), (_size), 1)
*(_resultp) = bit_ff_area_at_((_bitstr), 0, (_nbits), (_size), 0)