Question

When a CPU executes the instructions in a program, it is engaged in what process?

Short answer

Question: Briefly explain the process a CPU undergoes when it executes the instructions in a program. Answer: When a CPU executes instructions in a program, it undergoes the instruction cycle, also known as the fetch-decode-execute cycle. This cycle consists of three main steps: fetching the instruction from memory, decoding the instruction to determine the operation and operands, and executing the operation. The CPU's Program Counter (PC) helps keep track of the memory address of the current instruction.

Step-by-step solution

Introduction to CPU

The CPU (Central Processing Unit) is the main component of a computer system, responsible for executing instructions of a program. These instructions are stored in the computer's memory and are fetched, decoded, and executed by the CPU. The process the CPU undergoes while executing instructions is referred to as the instruction cycle or fetch-decode-execute cycle.

Fetch Instruction

In the first step, the CPU fetches the next instruction to be executed from the computer's memory (RAM). The instruction is stored in a specific memory address, and the CPU uses an internal register called the Program Counter (PC) to keep track of the memory address of the current instruction.

Decode Instruction

Once the instruction is fetched, the CPU decodes it to determine the operation that needs to be performed, such as addition, subtraction, or comparison. This process involves identifying the opcode (operation code), which is a specific numeric value representing the operation, and the operands or data required for the operation.

Execute Instruction

In the final step, the CPU performs the operation specified by the opcode, using the operands provided. The result is then stored in a CPU register or written back to memory.

Conclusion

When a CPU executes the instructions in a program, it is engaged in the instruction cycle or fetch-decode-execute cycle. This cycle consists of three main steps: fetching the instruction from memory, decoding the instruction to determine the operation and operands, and executing the operation.