IB_SCTS
CLR(sc->sc_imrb, IB_SCTS|IB_SDCD);
single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);
MFP->mf_ierb |= IB_SCTS|IB_SDCD;
MFP->mf_imrb &= ~(IB_SCTS|IB_SDCD);
sc->sc_imrb = IB_SCTS|IB_SDCD;
if ((MFP->mf_imrb & (IB_SCTS|IB_SDCD)) != sc->sc_imrb) {
single_inst_bclr_b(MFP->mf_imrb, IB_SCTS|IB_SDCD);