ATW_NEXTTX
htole32(ATW_CDTXADDR(sc, ATW_NEXTTX(i)));
for (i = txs->txs_firstdesc;; i = ATW_NEXTTX(i)) {
seg++, nexttx = ATW_NEXTTX(nexttx)) {
for (seg = sc->sc_txnext;; seg = ATW_NEXTTX(seg)) {