Learn: The Fetch-Decode-Execute Cycle

Welcome!Today, we'll explore the Fetch-Decode-Execute Cycle. This is a fundamental process carried out by the CPU to execute instructions. Let's break it down step by step!

What is the Fetch-Decode-Execute Cycle?The Fetch-Decode-Execute Cycle is the sequence of steps the CPU follows to process instructions in a program. It consists of fetching an instruction, decoding it, and executing it. This cycle is repeated continuously to make the computer function.

Step 1: FetchDuring the fetch step, the CPU retrieves an instruction from memory. The Program Counter (PC) holds the address of the next instruction, and the Memory Address Register (MAR) is used to locate that address in memory.

Step 2: DecodeOnce the instruction is fetched, the CPU decodes it to understand what action is required. The Current Instruction Register (CIR) holds the instruction being decoded. The Control Unit interprets the instruction and prepares other parts of the CPU for execution.

Step 3: ExecuteDuring the execute step, the CPU performs the action specified by the instruction. The Arithmetic Logic Unit (ALU) is responsible for calculations and logical operations, and the results may be stored in the Accumulator (ACC).

How Registers Work TogetherRegisters like the PC, MAR, MDR, CIR, and ACC work in coordination during the Fetch-Decode-Execute Cycle. They store addresses, data, and instructions temporarily to allow the CPU to execute tasks efficiently.

Review Time!Great work! You've learned about the Fetch-Decode-Execute Cycle and its key steps and components. Now, let's review and test your understanding.