FullDuplex
new_tx_mode = np->tx_mode & ~FullDuplex; /* duplex setting */
new_tx_mode |= FullDuplex;
tp->csr6 = 0x82420000 | (tp->sym_advertise & 0x0040 ? FullDuplex : 0);
if (dr32(MacMode) & FullDuplex)
macmode |= FullDuplex;
macmode &= ~FullDuplex;
if (tp->full_duplex) new_csr6 |= FullDuplex;
else new_csr6 &= ~FullDuplex;
if ((options[board_idx] & FullDuplex) || full_duplex[board_idx] > 0)
PutByte(XIRCREG1_ECR, GetByte(XIRCREG1_ECR) | FullDuplex);