Learn: The Fetch-Decode-Execute Cycle

Welcome!Building on what you've already learned about the CPU and its importance, we'll explore how it processes instructions using the Fetch-Decode-Execute Cycle.

What is the Fetch-Decode-Execute Cycle?The Fetch-Decode-Execute Cycle is the process the CPU uses to carry out instructions from a program. It involves fetching the instruction, decoding it to understand what to do, and executing it to perform the operation.

Step 1: FetchThe CPU retrieves the next instruction from memory using the Memory Address Register (MAR) and the Memory Data Register (MDR). The address of the next instruction is stored in the Program Counter (PC).

Step 2: DecodeOnce the instruction is fetched, the Control Unit (CU) interprets it. Decoding involves converting the instruction into signals that tell the CPU what action to perform.

Step 3: ExecuteIn the execute stage, the Arithmetic Logic Unit (ALU) performs operations such as calculations or logical comparisons. The Accumulator temporarily holds the result of these operations.

The Registers InvolvedSeveral registers play key roles in the cycle: Program Counter (PC) stores the address of the next instruction, Memory Address Register (MAR) holds the memory location, Memory Data Register (MDR) stores the data fetched from memory, and Accumulator holds intermediate results.

Review Time!Great work! You've learned about the Fetch-Decode-Execute Cycle and how the CPU processes instructions. Now let's test your understanding with a few questions.