CPU Organization MCQs

By: Prof. Dr. Fazal Rehman | Last updated: June 19, 2025

1. : What is the main function of the Arithmetic Logic Unit (ALU) in the CPU?
(A) To manage memory
(B) To execute arithmetic and logical operations
(C) To control data flow
(D) To handle input/output operations

2. : Which part of the CPU is responsible for fetching instructions from memory?
(A) ALU
(B) Control Unit
(C) Register
(D) Cache

3. : What does the Control Unit (CU) do in a CPU?
(A) Executes arithmetic calculations
(B) Manages the data transfer between components
(C) Fetches and decodes instructions
(D) Stores data temporarily

4. : Which register holds the address of the next instruction to be executed?
(A) Accumulator
(B) Instruction Register (IR)
(C) Program Counter (PC)
(D) Memory Address Register (MAR)

5. : What is the purpose of the Instruction Register (IR) in the CPU?
(A) To hold the address of the next instruction
(B) To store the result of arithmetic operations
(C) To hold the current instruction being executed
(D) To manage data transfer between the CPU and memory

6. : Which component of the CPU performs data manipulation and computation operations?
(A) Control Unit
(B) Memory Unit
(C) Arithmetic Logic Unit (ALU)
(D) Register Unit

7. : What is the function of the Memory Address Register (MAR)?
(A) To store the data to be written
(B) To hold the address of data in memory
(C) To execute arithmetic operations
(D) To manage input/output operations

8. : Which register temporarily holds data that is being transferred between memory and the CPU?
(A) Accumulator
(B) Data Register
(C) Memory Buffer Register (MBR)
(D) Instruction Register

9. : What does the Program Counter (PC) do during the execution of a program?
(A) Holds the result of the arithmetic operation
(B) Points to the location of the next instruction
(C) Manages data transfer between the CPU and peripherals
(D) Stores temporary data

10. : In a CPU, what is the role of the accumulator?
(A) To store data temporarily during processing
(B) To hold the address of the next instruction
(C) To fetch and decode instructions
(D) To control the timing of operations

11. : Which unit in the CPU controls the execution of instructions by directing the ALU and registers?
(A) Arithmetic Logic Unit
(B) Control Unit
(C) Memory Address Register
(D) Data Register

12. : What does the term “pipelining” refer to in CPU organization?
(A) Executing multiple instructions simultaneously
(B) Storing data temporarily in cache memory
(C) Fetching, decoding, and executing multiple instructions in overlapping stages
(D) Managing the flow of data between the CPU and external devices

13. : Which type of CPU register is used to hold intermediate results during computation?
(A) Program Counter
(B) Instruction Register
(C) Accumulator
(D) Memory Address Register

14. : What is the primary purpose of cache memory in a CPU?
(A) To provide additional storage for data
(B) To speed up data access by storing frequently used instructions and data
(C) To manage memory addresses
(D) To execute complex arithmetic operations

15. : Which part of the CPU is responsible for decoding instructions?
(A) Arithmetic Logic Unit
(B) Memory Address Register
(C) Control Unit
(D) Cache

16. : What does a CPU’s clock speed measure?
(A) The rate at which instructions are executed
(B) The size of the CPU’s cache
(C) The amount of data stored in the CPU
(D) The frequency of the clock signal driving the CPU

17. : In CPU architecture, what is the purpose of the bus interface unit?
(A) To manage data transfer between the CPU and memory
(B) To decode and execute instructions
(C) To control the flow of power to the CPU
(D) To store temporary data during computations

18. : What is the function of the status register in the CPU?
(A) To store the next instruction to be executed
(B) To hold intermediate results of operations
(C) To keep flags that indicate the status of the CPU (e.g., overflow, carry)
(D) To manage data transfers between the CPU and peripherals

19. : Which register is used to store the results of operations before they are written back to memory or used in further computations?
(A) Instruction Register
(B) Program Counter
(C) Accumulator
(D) Memory Buffer Register

20. : What does the term “context switching” refer to in CPU operation?
(A) Switching between different levels of cache
(B) Changing the current executing process to another process
(C) Updating the status register with new flags
(D) Transferring data between the CPU and memory

21. : Which component of the CPU is responsible for managing interrupts?
(A) Control Unit
(B) Arithmetic Logic Unit
(C) Memory Address Register
(D) Data Register

22. : What is the role of the instruction decoder in the CPU?
(A) To execute arithmetic operations
(B) To decode the binary representation of instructions into a format that the CPU can execute
(C) To store instructions temporarily
(D) To manage data transfers between the CPU and memory

23. : What is meant by the term “instruction set architecture” (ISA)?
(A) The physical arrangement of CPU components
(B) The set of instructions that the CPU can execute
(C) The design of the CPU’s cache system
(D) The speed at which the CPU operates

24. : Which unit in the CPU is responsible for performing arithmetic operations?
(A) Control Unit
(B) Arithmetic Logic Unit (ALU)
(C) Memory Address Register
(D) Instruction Register

25. : What does the term “data path” refer to in CPU organization?
(A) The route through which data is transferred within the CPU
(B) The path used for instruction decoding
(C) The connection between the CPU and peripheral devices
(D) The memory location used for data storage

26. : Which register is responsible for holding data that is being read from or written to memory?
(A) Program Counter
(B) Data Register
(C) Memory Address Register
(D) Instruction Register

27. : What is the main function of the fetch-execute cycle in CPU operations?
(A) To decode instructions
(B) To manage data transfers
(C) To retrieve an instruction from memory and execute it
(D) To handle interrupts

28. : Which component of the CPU is responsible for ensuring that the CPU performs operations correctly and efficiently?
(A) Control Unit
(B) Arithmetic Logic Unit
(C) Memory Address Register
(D) Status Register

29. : In CPU architecture, what does “superscalar” mean?
(A) A design that allows multiple instructions to be executed in parallel
(B) A technique for increasing clock speed
(C) A type of cache memory
(D) A method for managing interrupts

30. : Which component manages the flow of data and instructions between the CPU and other components of the computer?
(A) Data Bus
(B) Address Bus
(C) Control Unit
(D) Memory Address Register

31. : What does the term “microarchitecture” refer to in the context of CPU design?
(A) The high-level design and features of the CPU
(B) The specific implementation and layout of the CPU’s internal components
(C) The set of instructions the CPU can execute
(D) The software that controls CPU operations

32. : Which register is used to store the address of the next instruction to be fetched?
(A) Instruction Register
(B) Accumulator
(C) Program Counter
(D) Data Register

33. : What is the purpose of the stack pointer in CPU operations?
(A) To hold the address of the next instruction
(B) To manage the CPU’s cache
(C) To point to the top of the stack in memory
(D) To store intermediate results of computations

34. : Which part of the CPU handles the execution of branch instructions?
(A) Control Unit
(B) Arithmetic Logic Unit
(C) Memory Address Register
(D) Data Register

35. : In CPU organization, what does “out-of-order execution” refer to?
(A) Executing instructions in the order they appear in the program
(B) Executing instructions based on their availability rather than their order
(C) Managing memory access operations
(D) Decoding instructions before fetching them

36. : What is the function of the data cache in a CPU?
(A) To store data that has been recently accessed to speed up future access
(B) To manage the execution of instructions
(C) To control the flow of power to the CPU
(D) To hold the address of the next instruction

37. : Which unit is responsible for managing the data flow within the CPU and to/from memory?
(A) Arithmetic Logic Unit
(B) Control Unit
(C) Data Path
(D) Memory Address Register

38. : Which CPU component is responsible for handling interrupts and exceptions during program execution?
(A) Control Unit
(B) Interrupt Controller
(C) Arithmetic Logic Unit
(D) Instruction Register

39. : What does the term “hazard” refer to in CPU pipelining?
(A) A delay caused by resource conflicts or data dependencies
(B) A type of instruction cache miss
(C) A register storing intermediate results
(D) An error in instruction decoding

40. : Which technique is commonly used to resolve data hazards in pipelined CPUs?
(A) Instruction Fetching
(B) Branch Prediction
(C) Forwarding (or Bypassing)
(D) Caching

41. : What is the function of the program counter (PC) in a CPU?
(A) To store the current instruction being executed
(B) To hold the address of the next instruction to be fetched
(C) To manage arithmetic calculations
(D) To decode instructions

42. : Which type of CPU architecture executes multiple instructions simultaneously using multiple execution units?
(A) Scalar Architecture
(B) Superscalar Architecture
(C) RISC Architecture
(D) CISC Architecture

43. : What is the main advantage of using cache memory in a CPU?
(A) To increase the instruction set size
(B) To provide faster access to frequently used data and instructions
(C) To execute instructions in parallel
(D) To decode complex instructions

44. : In a CPU, what is a “stall”?
(A) An interruption caused by power failure
(B) A delay introduced to resolve hazards or wait for resources
(C) An instruction that executes instantly
(D) A type of register used for temporary storage

45. : Which CPU design feature allows the processor to continue execution by guessing the outcome of branches?
(A) Pipelining
(B) Speculative Execution
(C) Interrupt Handling
(D) Multithreading

46. : What is the role of the “decode” stage in a CPU pipeline?
(A) To fetch the instruction from memory
(B) To interpret the instruction and generate control signals
(C) To execute arithmetic or logic operations
(D) To write back results to registers

47. : Which type of memory is directly accessible by the CPU and has the fastest access time?
(A) Hard Disk
(B) Cache Memory
(C) Main Memory (RAM)
(D) Virtual Memory

48. : In CPU architecture, what does SIMD stand for?
(A) Single Instruction, Multiple Data
(B) Single Instruction, Multiple Devices
(C) Simple Instruction, Multiple Data
(D) Simultaneous Instruction, Multiple Data

49. : What is the purpose of the “write-back” stage in a CPU pipeline?
(A) To fetch instructions from memory
(B) To execute the instruction
(C) To write the computed result back to a register or memory
(D) To decode the instruction

50. : Which CPU design concept improves performance by overlapping the execution of multiple instructions?
(A) Multithreading
(B) Pipelining
(C) Cache Memory
(D) Branch Prediction