Learn: The Fetch-Decode-Execute Cycle

Welcome!Building on what you've already learned about why the CPU is essential, today we'll explore how instructions are processed using the Fetch-Decode-Execute Cycle. This is a key process that helps the CPU perform tasks efficiently.

What is the Fetch-Decode-Execute Cycle?The Fetch-Decode-Execute Cycle is the process the CPU uses to run instructions. It involves fetching the instruction from memory, decoding what it means, and executing it. This happens repeatedly and quickly, allowing the computer to operate smoothly.

Step 1: FetchDuring the Fetch step, the CPU retrieves the instruction from memory. The Program Counter (PC) points to the memory address of the next instruction, and this address is sent to the Memory Address Register (MAR).

Step 2: DecodeIn the Decode step, the CPU interprets the fetched instruction. The instruction is sent to the Control Unit (CU), which determines what needs to be done next. This step ensures the CPU understands how to process the instruction.

Step 3: ExecuteIn the Execute step, the CPU carries out the instruction. This might involve performing calculations in the Arithmetic Logic Unit (ALU), accessing memory, or managing data. This is the final step before the cycle repeats.

Review Time!Great work! You've learned about the steps of the Fetch-Decode-Execute Cycle and the roles of key CPU components. Now let's test your understanding with a few questions.