OPENPIC_PCPU_TPR
openpic_write(sc, OPENPIC_PCPU_TPR(cpu), 15);
openpic_write(sc, OPENPIC_PCPU_TPR(cpu), 0);
sc->sc_saved_prios[i] = bus_read_4(sc->sc_memr, OPENPIC_PCPU_TPR(i));
bus_write_4(sc->sc_memr, OPENPIC_PCPU_TPR(i), sc->sc_saved_prios[i]);