In a basic CPU instruction cycle, what is the initial stage where the next instruction is retrieved from memory?

In a basic CPU instruction cycle, what is the initial stage where the next instruction is retrieved from memory?

• A. Fetch
• B. Decode
• C. Execute
• D. Store

Answer: (A)

The initial stage is fetching the instruction. In a basic CPU cycle, you must first retrieve the next instruction from memory so the processor has the actual bits to work with. The program counter tells the CPU where that instruction lives; these bits are loaded into the instruction register and the PC is typically advanced to point to the following instruction. Without fetching, there’s nothing to decode or execute. Once the instruction is fetched, the next step is decoding its opcode and operands, then executing the operation, and finally storing any results back to registers or memory. So fetch is the starting point because it supplies the instruction data that drives the rest of the cycle.

The initial stage is fetching the instruction. In a basic CPU cycle, you must first retrieve the next instruction from memory so the processor has the actual bits to work with. The program counter tells the CPU where that instruction lives; these bits are loaded into the instruction register and the PC is typically advanced to point to the following instruction. Without fetching, there’s nothing to decode or execute.

Once the instruction is fetched, the next step is decoding its opcode and operands, then executing the operation, and finally storing any results back to registers or memory. So fetch is the starting point because it supplies the instruction data that drives the rest of the cycle.