A processor can be understood as stored state connected by combinational logic. Registers hold the current machine state; a datapath transforms values; control signals decide which transformation and state updates an instruction requires.

Datapath

Arithmetic units, multiplexers and connections move operands from registers, perform operations and route results toward registers or memory interfaces.

Control

The instruction's encoded fields determine control choices such as which registers to read, which arithmetic operation to perform and where the result should go.

Clocked state transitions

Combinational logic computes from the current state between clock edges. At an active edge, selected registers capture the next state. Repeated state transitions implement the instruction sequence.

current registers
      ↓
 decode + combinational datapath
      ↓
next register values
      ↓ clock edge
updated registers

This simple model connects logic gates and registers to the abstract fetch/decode/execute model. Modern processors add pipelines, caches and speculative execution, but still implement an architectural state transition compatible with their instruction set.