AR_INTR_SYNC_ENABLE
AR_WRITE(sc, AR_INTR_SYNC_ENABLE, sc->isync);
AR_WRITE(sc, AR_INTR_SYNC_ENABLE, 0);
(void)AR_READ(sc, AR_INTR_SYNC_ENABLE);
AR_WRITE(sc, AR_INTR_SYNC_ENABLE, sc->isync);
AR_WRITE(sc, AR_INTR_SYNC_ENABLE, 0);