SIOP_SIST1
reg |= siop_sgc_r1(v, h, SIOP_SIST1) << 8;
reg |= siop_gsc_r1(v, h, SIOP_SIST1) << 8;
sist1 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SIST1);