I595_XMT_HDRLEN
ecp->ec_multicnt, len + I595_XMT_HDRLEN, avail);
sc->tx_end = sc->rx_size + I595_XMT_HDRLEN + len;
if ((len+pad+2*I595_XMT_HDRLEN) > avail) {
end = last + pad + len + I595_XMT_HDRLEN;
if ((sc->sram - last) <= I595_XMT_HDRLEN) {
end = last + pad + len + I595_XMT_HDRLEN;