CPU Functions

Which register holds the address of the next instruction to be fetched?

• Program Counter

• Accumulator

• Memory Data Register

• Control Unit

Answer explanation

The Program Counter (PC) holds the address of the next instruction to be fetched in a CPU. It increments after each instruction is fetched, ensuring the CPU executes instructions in the correct sequence.

What is the role of the Memory Address Register (MAR)?

• Holds the address of the next instruction

• Stores intermediate arithmetic results

• Holds the address of memory being accessed

• Controls the execution of instructions

Answer explanation

The Memory Address Register (MAR) holds the address of the memory being accessed. It is crucial for fetching instructions and data from memory, making it essential for the CPU's operation.

Which bus carries memory addresses?

• Data Bus

• Control Bus

• Address Bus

• Instruction Bus

Answer explanation

The Address Bus is responsible for carrying memory addresses from the CPU to other components, allowing the system to access specific locations in memory. Therefore, the correct answer is the Address Bus.

What does the Control Unit do?

• Stores intermediate values

• Manages CPU execution

• Carries addresses to memory

• Performs arithmetic operations

Answer explanation

The Control Unit manages CPU execution by directing the operation of the processor, coordinating the flow of data between the CPU and other components, and ensuring instructions are executed in the correct order.

Which register temporarily stores fetched data or instructions?

• MDR

• ALU

• PC

• MAR

Answer explanation

The MDR (Memory Data Register) temporarily stores fetched data or instructions from memory before they are processed. It acts as a buffer between the CPU and memory, making it essential for data handling.

What is the function of the Accumulator (ACC)?

• Stores results of calculations

• Holds program instructions

• Manages clock speed

• Carries signals to RAM

Answer explanation

The Accumulator (ACC) is a register in a computer's CPU that stores the results of calculations performed by the arithmetic logic unit (ALU). This makes 'Stores results of calculations' the correct answer.

What happens during the Decode phase of the FDE cycle?

• Instruction is retrieved

• Instruction is interpreted

• Instruction is executed

• Instruction is outputted

Answer explanation

During the Decode phase, the instruction is interpreted, meaning the CPU determines what action the instruction specifies. This is crucial for the subsequent execution phase.

Which of these is NOT a component of the CPU?

• ALU

• CU

• RAM

• PC

Answer explanation

RAM (Random Access Memory) is not a component of the CPU. The CPU consists of the ALU (Arithmetic Logic Unit), CU (Control Unit), and PC (Program Counter), which are all integral to its operation.

What is the function of the ALU?

• Performs calculations

• Manages memory

• Decodes instructions

• Holds registers

Answer explanation

The ALU (Arithmetic Logic Unit) is responsible for performing calculations and executing arithmetic and logical operations, making 'Performs calculations' the correct choice.

Which CPU architecture uses shared memory for instructions and data?

• Harvard

• Von Neumann

• ARM

• RISC

Answer explanation

The Von Neumann architecture uses a single shared memory for both instructions and data, allowing the CPU to fetch instructions and data from the same memory space. In contrast, Harvard architecture has separate memory for instructions and data.