Learn: Fetch-Decode-Execute Cycle

Welcome!Today we'll learn about the fetch-decode-execute (FDE) cycle, which is a key process that happens inside the CPU. It's an essential concept in Computer Science, so let's break it down step by step!

What is the Fetch-Decode-Execute Cycle?Computers process instructions using the fetch-decode-execute cycle. This cycle allows the CPU to fetch data and instructions, decode them, and execute the required task. It repeats continuously to ensure the computer runs smoothly.

Step 1: FetchDuring the fetch phase, the CPU retrieves an instruction from memory. The Program Counter (PC) holds the address of the next instruction, and the Memory Address Register (MAR) sends this address to memory. The Memory Data Register (MDR) collects the data or instruction at that address.

Step 2: DecodeOnce the instruction is fetched, it moves to the Control Unit (CU). The CU decodes the instruction to understand what needs to be done. This involves identifying whether the instruction requires calculations, data movement, or other tasks.

Step 3: ExecuteDuring the execute phase, the CPU performs the operation specified by the instruction. If calculations are needed, the Arithmetic Logic Unit (ALU) handles them. Other tasks might involve moving data or interacting with devices.

Review Time!Great work! You've learned about how the CPU processes instructions using the fetch-decode-execute cycle. Now let's test your understanding with a few questions.