siop_gsc_r1
reg = siop_gsc_r1(v, h, SIOP_SIST0);
reg |= siop_gsc_r1(v, h, SIOP_SIST1) << 8;
uint8_t siop_gsc_r1(void *, bus_space_handle_t, bus_size_t);
gsc->sc_bustag.hbt_r1 = siop_gsc_r1;