Computer Architecture 2075( Old Course)

Answered by: Ranjit Shrestha

Hardwired Control Unit

1. Hardwired control unit generates the control signals needed for the processor using logic circuits 2. Hardwired control unit is faster when compared to microprogrammed control unit as the required control signals are generated with the help of hardwares 3. Difficult to modify as the control signals that need to be generated are hard wired 4. More costlier as everything has to be realized in terms of logic gates 5. It cannot handle complex instructions as the circuit design for it becomes complex 6. Only limited number of instructions are used due to the hardware implementation 7. Used in computer that makes use of Reduced Instruction Set Computers(RISC)

Microprogrammed Control Unit 1. Micrprogrammed control unit generates the control signals with the help of micro instructions stored in control memory 2. This is slower than the other as micro instructions are used for generating signals here 3.Easy to modify as the modification need to be done only at the instruction level 4.Less costlier than hardwired control as only micro instructions are used for generating control signals 5. It can handle complex instructions 6. Control signals for many instructions can be generated 7.Used in computer that makes use of Complex Instruction Set Computers(CISC)