PUTRFD16
PUTRFD16(rfd, RFD_CTL_OFFSET, RFD_CTL_EL);
PUTRFD16(rfd, RFD_SIZ_OFFSET, RFD_SIZE - RFD_PKT_OFFSET);
PUTRFD16(rfd, RFD_CNT_OFFSET, 0);
PUTRFD16(lfd, RFD_CTL_OFFSET, 0);