which of the following statements about the fetch-decode-execute cycle in a CPU are correct?
I. The Program Counter is incremented after each instruction is fetched so the CPU moves to the next instruction.
II. The Control Unit is responsible for fetching instructions and placing them in the Instruction Register.
III. The ALU is responsible for decoding instructions and determining which operation to perform.
IV. Registers are used to permanently store operating system files for fast access.
Explanation
To identify the correct statements, we analyze the components of the fetch-decode-execute cycle:
Statement I: This is correct. The Program Counter (PC) holds the address of the next instruction and is updated (incremented) during the fetch phase to point to the next instruction in memory.
Statement II: This is correct. The Control Unit (CU) coordinates the fetching of instructions from memory and directs them into the Instruction Register (IR) for subsequent decoding.
Statement III: This is incorrect. The Arithmetic Logic Unit (ALU) performs arithmetic and logical operations. The decoding of instructions is the responsibility of the Control Unit, not the ALU.
Statement IV: This is incorrect. Registers are volatile, high-speed storage locations within the CPU used for temporary data; they are not used for permanent storage of operating system files.
Since only statements I and II are correct, the correct option is (d).
Correct Option: (d) I and II
