The processing unit
First topic: The datapath
- Functional units operate on data
- ALU, adders, multipliers, ROM lookup tables, etc.
- Registers store and shift data and addresses
- Program counter, shifters, registers
Second topic: The controller
- Finite state machine coordinates the processor’s operations
- Instructions (fetch, decode, execute) tell the FSM what to do
- Inputs = machine instruction, datapath conditions
- Outputs = register-transfer control signals, ALU op codes