EMAC_DM646X_INTPRESCALE_MASK
addnl_dvdr = EMAC_DM646X_INTPRESCALE_MASK / prescale;
int_ctrl &= (~EMAC_DM646X_INTPRESCALE_MASK);
int_ctrl |= (prescale & EMAC_DM646X_INTPRESCALE_MASK);