W3_MAC_CONTROL
mctl = GET16(W3_MAC_CONTROL);
PUT16(W3_MAC_CONTROL, mctl);
PUT16(W3_MAC_CONTROL, GET16(W3_MAC_CONTROL) |
mctl = GET16(W3_MAC_CONTROL);
PUT16(W3_MAC_CONTROL, mctl);
sc->ex_duplex = GET16(W3_MAC_CONTROL) & MAC_CONTROL_FDX ?