Learn: The Fetch-Decode-Execute Cycle

Welcome!Building on what you've already learned about why the CPU is essential, we’ll now explore how it processes instructions through the Fetch-Decode-Execute Cycle.

What is the Fetch-Decode-Execute Cycle?The Fetch-Decode-Execute Cycle is the process used by the CPU to run instructions. It ensures all tasks in a computer are completed efficiently and accurately.

Step 1: FetchDuring the fetch step, the CPU retrieves the instruction from memory. The Memory Address Register (MAR) holds the memory location, while the Program Counter (PC) keeps track of the next instruction’s address.

Step 2: DecodeIn the decode step, the CPU analyses the instruction to understand what it needs to do. The Control Unit (CU) plays a key role by interpreting the instruction and preparing the necessary resources.

Step 3: ExecuteThe execute step is where the instruction is carried out. Tasks like calculations or memory access are performed by the Arithmetic Logic Unit (ALU). Results may be temporarily stored in the Accumulator.

Why Does the Fetch-Decode-Execute Cycle Matter?This cycle is essential for the CPU to carry out all instructions step by step. It ensures computers perform tasks accurately, from simple calculations to complex processes.

Review Time!Great work! You've learned about the Fetch-Decode-Execute Cycle and the role of CPU components. Let’s test your understanding with a few final questions.