INT2_MAP_MASK0
bus_space_write_1(iot, ioh, INT2_MAP_MASK0, 0);
mmask = bus_space_read_1(iot, ioh, INT2_MAP_MASK0 + (which << 2));
mask = bus_space_read_1(iot, ioh, INT2_MAP_MASK0);
bus_space_write_1(iot, ioh, INT2_MAP_MASK0, mask);