Instruction decoding produces controls signals for the datapath and memory. The inputs to control circuitry are the opcode and function fields of the instruction. It generates the following kinds of control signals.

• read and write control signals for data memory
• write control signal for registers
• multiplexer controls for routing data through the datapath
• control signal to select an appropriate ALU operation
• control signal to control PC update

Instruction decode is the same for all instructions.