private void fillData(){
        for (AbstractUnit unit : units) {
            if(unit instanceof IOutputUnit ){
                IInstructionUnit nextUnit = (IInstructionUnit) ((IOutputUnit)unit).getNextUnit();
                if(nextUnit == null){
//                    tulip.Tulip.mainFrame.writeConsole("unit №"+unit.unitNumber+ " has no next unit");
//                    unit.color = Color.BLUE;
                }else
                if(unit instanceof DataUnit){
                    DataUnit dataUnit = (DataUnit)unit;
                    nextUnit.setOperand(dataUnit.getData(), dataUnit.position.ordinal());
                }else
                if(unit instanceof IOutputUnit){
                    nextUnit.setOperand("_", unit.position.ordinal());
                }
            }
        }
    }