dz_read1
status = dz_read1(sc, sc->sc_dr.dr_dcd) | sc->sc_dsr;
status = dz_read1(sc, sc->sc_dr.dr_ring);
status = dz_read1(sc, sc->sc_dr.dr_dtr);
dz_write1(sc, sc->sc_dr.dr_dtr, dz_read1(sc, sc->sc_dr.dr_dtr) | bit);
dz_write1(sc, sc->sc_dr.dr_dtr, dz_read1(sc, sc->sc_dr.dr_dtr) & ~bit);
if ((dz_read1(sc, sc->sc_dr.dr_dcd) | sc->sc_dsr) & bit) {