EPIC_CDTX
txd = EPIC_CDTX(sc, nexttx);
EPIC_CDTX(sc, sc->sc_txlast)->et_control |= ET_TXCTL_IAF;
EPIC_CDTX(sc, firsttx)->et_txstatus |= ET_TXSTAT_OWNER;
txd = EPIC_CDTX(sc, i);
txd = EPIC_CDTX(sc, i);