In the design of a control unit of a processor, two common approaches are used: hardware control and microprogrammed control. Consider the following statements: 

1. Hardware control units are generally faster but more difficult to modify than microprogrammed control units. 
2. In a horizontal microprogrammed control unit, each control signal has a separate bit in the control word. 
3. Vertical microprogramming leads to longer control words but provides greater parallelism. 
4. Microprogrammed control units are typically easier to implement and modify than hardware control units.

• Statement 1 – True: Hardware control units are implemented using combinational logic circuits. They generate control signals directly through hardware, making them faster but difficult to modify since any change requires redesigning the hardware.
• Statement 2 – True: In a horizontal microprogrammed control unit, each control signal is represented by a dedicated bit in the control word. This allows maximum parallelism but results in a wide (long) control word.
• Statement 3 – False: In vertical microprogramming, control words use encoded fields to represent control signals. This makes the word shorter, not longer, but reduces parallelism since only a few signals can be activated at once.
• Statement 4 – True: Microprogrammed control units are easier to implement and modify because control logic is stored in a control memory (microprograms). Modifications can be done by changing microinstructions instead of redesigning hardware.

✅ Correct statements: 1, 2, and 4