MII_RD4
v = (MII_RD4(sc, reg+0) & 0xff) << 0;
v |= (MII_RD4(sc, reg+4) & 0xff) << 8;
v |= (MII_RD4(sc, reg+8) & 0xff) << 16;
v |= (MII_RD4(sc, reg+12) & 0xff) << 24;