cas_post_rxds_ringN
cas_post_rxds_ringN(cp, 1, 0);
cas_post_rxds_ringN(cp, 1, RX_DESC_RINGN_SIZE(1) -
cas_post_rxds_ringN(cp, 0, 0);
cas_post_rxds_ringN(cp, 0, RX_DESC_RINGN_SIZE(0) -
if (cas_post_rxds_ringN(cp, i, cp->rx_last[i]) < 0) {