Learn: The Fetch-Decode-Execute Cycle

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

What is the Fetch-Decode-Execute Cycle?The Fetch-Decode-Execute Cycle is the process the CPU uses to run instructions. It happens continuously while the computer is powered on, ensuring tasks are completed efficiently. Each step ensures the CPU understands and carries out the instruction.

Step 1: FetchDuring the fetch step, the CPU retrieves the next instruction from memory. The Program Counter (PC) provides the address and the Memory Address Register (MAR) temporarily stores it. The instruction is then fetched from memory and stored in the Memory Data Register (MDR).

Step 2: DecodeOnce fetched, the CPU decodes the instruction to understand what needs to be done. This is handled by the Control Unit (CU), which interprets the data and prepares the CPU components for execution.

Step 3: ExecuteIn the execute step, the CPU carries out the instruction. The Arithmetic Logic Unit (ALU) handles calculations and logical comparisons, while the Accumulator stores the result temporarily.

Why is the Fetch-Decode-Execute Cycle Important?This cycle ensures the CPU can process instructions quickly and accurately, allowing computers to perform tasks efficiently. Without it, the CPU wouldn't know how to handle instructions stored in memory.

Review Time!Great work! You've learned about the key steps and components of the Fetch-Decode-Execute Cycle. Let's test your understanding with some final questions.