Vaidikalaya

MCQ On CPU Registers

Q1. What is the primary function of a CPU register?.
  1. To store large amounts of data for long-term use.
  2. To provide high-speed, temporary storage for data and instructions currently being used by the CPU.
  3. To handle input and output operations with peripheral devices.
  4. To manage virtual memory and swap space on a hard drive.

Answer: b, To provide high-speed, temporary storage for data and instructions currently being used by the CPU.

Q2. The register that holds the address of the next instruction to be fetched from memory is the:.
  1. Instruction Register (IR)
  2. Memory Address Register (MAR)
  3. Program Counter (PC)
  4. Accumulator (AC)

Answer: c, Program Counter (PC)

Q3. Which register holds the instruction currently being executed or decoded?.
  1. Storing the address of the next instruction to be executed.
  2. Holding the memory address of the data to be accessed.
  3. Instruction Register (IR)
  4. Temporarily storing the result of an arithmetic or logical operation.

Answer: c, Instruction Register (IR)

Q4. Which type of register is often used to hold intermediate results of arithmetic and logical operations?.
  1. Memory Address Register (MAR)
  2. Accumulator (AC)
  3. Program Counter (PC)
  4. Memory Data Register (MDR)

Answer: b, Accumulator (AC)

Q5. The Memory Address Register (MAR) and Memory Data Register (MDR) help the CPU communicate with which component?.
  1. The CPU and the hard disk.
  2. The CPU and the main memory (RAM).
  3. The ALU and the control unit.
  4. The cache memory and the virtual memory.

Answer: b, The CPU and the main memory (RAM).

Q6. What is a key difference between General-Purpose Registers and Special-Purpose Registers?.
  1. General-Purpose Registers are always larger in size than Special-Purpose Registers.
  2. General-Purpose Registers can be used for various tasks, while Special-Purpose Registers are designated for a specific function.
  3. General-Purpose Registers are only accessible by the operating system, while Special-Purpose Registers can be used by any program.
  4. Special-Purpose Registers are visible to the user, while General-Purpose Registers are not.

Answer: b, General-Purpose Registers can be used for various tasks, while Special-Purpose Registers are designated for a specific function.

Q7. Which of the following registers is typically not accessible by the programmer?.
  1. Program Counter (PC)
  2. General-Purpose Registers
  3. Memory Address Register (MAR)
  4. Accumulator (AC)

Answer: c, Memory Address Register (MAR)

Q8. In a modern CPU, which register holds temporary data during calculations and logical operations?.
  1. Temporary Register (TR)
  2. Program Counter (PC)
  3. Instruction Register (IR)
  4. Memory Address Register (MAR)

Answer: a, Temporary Register (TR)

Q9. What does a "Flag" or "Status" register contain?.
  1. The address of the next instruction.
  2. The status of the CPU and the results of various operations.
  3. Data to be written to memory.
  4. The instruction currently being executed.

Answer: b, The status of the CPU and the results of various operations.

Q10. When an instruction is fetched from memory, it is first placed in which register?.
  1. Program Counter (PC)
  2. Memory Data Register (MDR)
  3. Memory Address Register (MAR)
  4. Instruction Register (IR)

Answer: d, Instruction Register (IR)

Q11. Which of the following registers holds the address of an instruction?.
  1. DR
  2. PC
  3. IR
  4. More than one of the above

Answer: b, PC

Q12. Which addressing mode is useful for initializing registers to a constant value?.
  1. implied mode
  2. immediate mode
  3. register mode
  4. register indirect mode

Answer: b, immediate mode

Q13. Which of the following is a group of bits that instructs the computer to perform a specific operation?.
  1. address
  2. memory
  3. program counter
  4. instruction code

Answer: d, instruction code

Q14. A register is defined as ___________.
  1. The group of latches for storing one bit of information
  2. The group of latches for storing n-bit of information
  3. The group of flip-flops suitable for storing one bit of information
  4. The group of flip-flops suitable for storing binary information

Answer: d, The group of flip-flops suitable for storing binary information

Solution: A register is defined as the group of flip-flops suitable for storing binary information. Each flip-flop is a binary cell capable of storing one bit of information. The data in a register can be transferred from one flip-flop to another.

Q15. The register is a type of ___________.
  1. Sequential circuit
  2. Combinational circuit
  3. CPU
  4. Latches

Answer: a, Sequential circuit

Solution: Register’s output depends on the past and present states of the inputs. The device which follows these properties is termed as a sequential circuit. Whereas, combinational circuits only depend on the present values of inputs.

Q16. The length of a register is called _______.
  1. word limit
  2. word size
  3. register limit
  4. register size

Answer: b, word size

Solution: The length of a register is called word size. It tells the number of bits a register can store. Registers are a part of the CPU.

Q17. The _________ holds the contents of the accessed memory word..
  1. MAR
  2. MBR
  3. PC
  4. IR

Answer: b, MBR

Solution: The MBR holds the contents of the accessed (read/written) memory word. MBR stands for Memory Buffer Register.

Q18. Which of the following is not a visible register?.
  1. General Purpose Registers
  2. Address Register
  3. Status Register
  4. MAR

Answer: d, MAR

Solution: MAR or the memory address register is not a visible register. This register is user inaccessible. It contains the address of the memory block to be read or written to.

Q19. What kind of a flag is the sign flag?.
  1. General Purpose
  2. Status
  3. Address
  4. Instruction

Answer: b, Status

Solution: Sign flag is a type of status register or the flag register. It is used to indicate the sign of certain bits.