SIOP_DMODE
dmode = readb(addr + SIOP_DMODE);
writeb(addr + SIOP_DMODE, dmode);
dmode = readb(addr + SIOP_DMODE);
writeb(addr + SIOP_DMODE, dmode);
dmode = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_DMODE);
bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_DMODE, dmode);