GATE CS 1987 Q1-vi — ALU, Data-path and Control Unit

A control unit can be designed using two main approaches: hardwired control and microprogrammed control.

• Hardwired Control Unit: Built using combinational and sequential logic circuits. It is extremely fast because control signals are generated directly by hardware, but it is rigid and difficult to modify or extend.
• Microprogrammed Control Unit: Control signals are generated by executing a sequence of microinstructions stored in a special control memory (ROM). Since instructions are defined by microprograms in memory, adding or modifying instructions only requires updating the control memory. This facilitates easy implementation of new instructions. However, because it requires memory access to fetch microinstructions, it is slower than a hardwired control unit.

Therefore, option B is the correct statement.