UCDC_LINE_RTS
SET(val, UCDC_LINE_RTS);
if (onoff && (sc->sc_lcr & UCDC_LINE_RTS)) return;
if (!onoff && !(sc->sc_lcr & UCDC_LINE_RTS)) return;
sc->sc_lcr = onoff ? sc->sc_lcr | UCDC_LINE_RTS
: sc->sc_lcr & ~UCDC_LINE_RTS;
(sc->sc_rts ? UCDC_LINE_RTS : 0);
(sc->sc_rts ? UCDC_LINE_RTS : 0);