The Fetch-and-Execute Cycle, or instruction cycle, is the basic operation cycle of a computer. It is the process (input -> process -> output) by which a computer retrieves a program instruction from its memory, determines what actions the instruction requires, and carries out those actions. This cycle is repeated continuously by the central processing unit (CPU), from bootup to when the computer is shut down.
The basic steps in a standard fetch execute cycle are: Fetch -> Decode -> Execute
Let’s look at the steps in more detail.