com_msr
sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);
sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);
sc->sc_msr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, com_msr);
c = bus_space_read_1(bst, bsh, com_msr);
[COM_REG_MSR] = com_msr,