VR_CDTX
d = VR_CDTX(sc, nexttx);
VR_CDTX(sc, sc->vr_txlast)->vr_ctl |= htole32(VR_TXCTL_FINT);
VR_CDTX(sc, firsttx)->vr_status = htole32(VR_TXSTAT_OWN);
d = VR_CDTX(sc, i);
d = VR_CDTX(sc, i);