E1000_RCTL_MO_SHIFT
rctl &= ~(3 << E1000_RCTL_MO_SHIFT);
(hw->mac.mc_filter_type << E1000_RCTL_MO_SHIFT);
preg |= (((mreg & E1000_RCTL_MO_3) >> E1000_RCTL_MO_SHIFT)