ALU Design MCQs

By: Prof. Dr. Fazal Rehman Shamil | Last updated: September 20, 2024

Which of the following components is part of the Arithmetic Logic Unit (ALU)?

A) Memory
B) Control Unit
C) Registers
D) Adder
Answer: D) Adder

The primary function of an ALU is to perform __________.
A) Memory management
B) Logical and arithmetic operations
C) Instruction fetching
D) Data storage
Answer: B) Logical and arithmetic operations

What does the ALU use to carry out arithmetic operations like addition and subtraction?
A) Control signals
B) Flip-flops
C) Accumulators
D) Adders and subtractors
Answer: D) Adders and subtractors

In a computer, the ALU is part of the __________.
A) Central Processing Unit (CPU)
B) Memory Unit
C) Input/Output System
D) Secondary Storage
Answer: A) Central Processing Unit (CPU)

Which operation is not performed by the ALU?
A) Addition
B) Subtraction
C) Program Counter update
D) Bitwise AND
Answer: C) Program Counter update

Which of the following logic operations is performed by an ALU?
A) OR operation
B) NAND operation
C) NOR operation
D) All of the above
Answer: D) All of the above

The ALU design includes a collection of __________.
A) Registers and memory
B) Multiplexers and logic gates
C) Control units
D) Instruction decoders
Answer: B) Multiplexers and logic gates

Which of the following is a common input to an ALU?
A) Program counter
B) Status register
C) Data and instruction
D) Control signals
Answer: C) Data and instruction

What does the ‘L’ in ALU stand for?
A) Large
B) Logic
C) Loop
D) Load
Answer: B) Logic

ALU outputs are directly connected to __________.
A) Accumulators
B) Registers
C) Program Counter
D) Control Unit
Answer: B) Registers

The control unit interacts with the ALU to perform __________.
A) Memory read/write
B) Arithmetic and logic operations
C) I/O operations
D) Interrupt handling
Answer: B) Arithmetic and logic operations

Which of the following arithmetic operations cannot be performed by a basic ALU?
A) Addition
B) Division
C) Subtraction
D) Multiplication
Answer: B) Division

How does an ALU perform a subtraction operation?
A) Using only an adder
B) By inverting the bits and adding
C) Using a subtractor
D) Using a multiplier
Answer: B) By inverting the bits and adding

ALU flags are used to indicate __________.
A) Execution speed
B) The result of an operation
C) Instruction types
D) Cache state
Answer: B) The result of an operation

Which flag in the ALU indicates that an arithmetic operation has generated a carry?
A) Zero flag
B) Carry flag
C) Overflow flag
D) Sign flag
Answer: B) Carry flag

The Zero Flag in an ALU is set when __________.
A) The result of an operation is non-zero
B) The result of an operation is zero
C) There is an overflow
D) A carry is generated
Answer: B) The result of an operation is zero

The ALU works in conjunction with the __________ to execute instructions.
A) Instruction Set Architecture (ISA)
B) Memory Management Unit (MMU)
C) Control Unit (CU)
D) Input/Output Unit (I/O)
Answer: C) Control Unit (CU)

What is the role of multiplexers in an ALU?
A) To select between different operations
B) To store intermediate results
C) To handle data input/output
D) To control memory access
Answer: A) To select between different operations

Which of the following is an example of a logical operation in an ALU?
A) Addition
B) Multiplication
C) OR
D) Division
Answer: C) OR

The Overflow Flag in an ALU is used to detect __________.
A) Zero result
B) Signed overflow
C) Unsigned carry
D) Even result
Answer: B) Signed overflow

The ALU’s shift operation is used to __________.
A) Shift data left or right
B) Add two numbers
C) Multiply numbers
D) Invert data bits
Answer: A) Shift data left or right

What is the primary role of the Accumulator in ALU operations?
A) Store results temporarily
B) Control instruction flow
C) Address memory locations
D) Decode instructions
Answer: A) Store results temporarily

Which part of the CPU fetches data for the ALU to process?
A) Memory
B) Control Unit
C) Cache
D) Registers
Answer: B) Control Unit

How is a multiplication operation typically performed in ALU design?
A) By repeatedly adding
B) Using a direct multiplier circuit
C) By repeatedly subtracting
D) Using division logic
Answer: A) By repeatedly adding

Which component signals the ALU on what operation to perform?
A) Status Register
B) Control Unit
C) Memory
D) Instruction Pointer
Answer: B) Control Unit

Which operation would cause the Carry Flag in an ALU to be set?
A) Subtraction without carry
B) Addition causing overflow
C) Logical AND
D) Multiplication by zero
Answer: B) Addition causing overflow

ALUs in modern processors can perform both integer and __________ arithmetic.
A) Floating-point
B) String-based
C) Symbolic
D) Character-based
Answer: A) Floating-point

In many ALU designs, which of the following operations can be performed using a left-shift operation?
A) Subtraction
B) Division by 2
C) Multiplication by 2
D) Addition of two numbers
Answer: C) Multiplication by 2

Which of the following units is responsible for handling conditional branches based on ALU operations?
A) Memory Unit
B) Instruction Fetch Unit
C) Control Unit
D) ALU Flags
Answer: C) Control Unit

Which of the following statements is true about the relationship between the ALU and the CPU?
A) The CPU controls the ALU
B) The ALU stores the instructions for the CPU
C) The ALU manages the I/O operations
D) The ALU is independent of the CPU
Answer: A) The CPU controls the ALU

Which of the following is a secondary function of the ALU?
A) Instruction decoding
B) Data comparison
C) Memory allocation
D) I/O processing
Answer: B) Data comparison

The Sign Flag in an ALU is set when __________.
A) The result is negative
B) The result is zero
C) A carry is generated
D) An overflow occurs
Answer: A) The result is negative

What component in the CPU typically provides operands for the ALU?
A) Cache
B) Register file
C) Hard drive
D) Control bus
Answer: B) Register file

Logical operations in an ALU generally involve __________.
A) Addition and subtraction
B) Multiplication and division
C) Bitwise operations
D) Floating-point arithmetic
Answer: C) Bitwise operations

Which of the following best describes an ALU in modern microprocessors?
A) A separate processing chip
B) A fixed-function hardware component
C) A programmable unit
D) A multi-core processing unit
Answer: B) A fixed-function hardware component

The ALU in a CPU performs shifts and rotates for __________.
A) Arithmetic only
B) Logical only
C) Both arithmetic and logical purposes
D) Memory purposes
Answer: C) Both arithmetic and logical purposes

Which of the following best describes the function of a half-adder in an ALU?
A) Performs logical XOR operations
B) Adds two binary digits without considering carry-in
C) Performs subtraction
D) Multiplies two binary numbers
Answer: B) Adds two binary digits without considering carry-in

A carry-lookahead adder improves ALU performance by __________.
A) Increasing the bit size
B) Reducing propagation delay
C) Storing intermediate values
D) Reducing memory access time
Answer: B) Reducing propagation delay

What is the role of a Barrel Shifter in some ALUs?
A) Multiplies two numbers quickly
B) Divides numbers by powers of 2
C) Shifts multiple bits simultaneously
D) Manages memory addressing
Answer: C) Shifts multiple bits simultaneously

In ALU design, a ripple carry adder is slower than a carry-lookahead adder because __________.
A) It requires more power
B) It propagates carry through each bit
C) It has more gates
D) It uses floating-point arithmetic
Answer: B) It propagates carry through each bit

Which logic gate is essential in the design of an ALU’s adder circuit?
A) AND gate
B) OR gate
C) XOR gate
D) NOR gate
Answer: C) XOR gate

What is the purpose of using multiplexers in ALU design?
A) To reduce circuit complexity
B) To select between different operations
C) To handle overflow detection
D) To store results
Answer: B) To select between different operations

Which type of arithmetic operations can be performed by the ALU without any additional components?
A) Integer division
B) Subtraction
C) Floating-point multiplication
D) Exponentiation
Answer: B) Subtraction

What is a combinational logic circuit used in the ALU for performing addition?
A) Full Adder
B) Latch
C) Multiplexer
D) Flip-flop
Answer: A) Full Adder

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• Introduction to Computer Architecture MCQs
  • Evolution of Computer Architecture MCQs
  • von Neumann vs Harvard Architecture MCQs
• Basic Components of a Computer System MCQs
  • Central Processing Unit (CPU) MCQs
  • Memory (RAM, ROM, Cache) MCQs
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  • Flags and Status Registers MCQs
• Instruction Set Architecture (ISA) MCQs
  • Types of Instructions (Data Movement, Arithmetic, Control) MCQs
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  • RISC (Reduced Instruction Set Computer) vs CISC (Complex Instruction Set Computer) MCQs
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  • Cache Mapping Techniques (Direct, Associative, Set-Associative) MCQs
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• Input/Output Organization MCQs
  • I/O Techniques (Polling, Interrupts, DMA) MCQs
  • I/O Mapping (Memory-Mapped I/O, Isolated I/O) MCQs
  • Interrupt Handling MCQs
• Bus Architecture MCQs
  • System Bus (Data, Address, Control) MCQs
  • Bus Arbitration MCQs
  • Synchronous vs Asynchronous Buses MCQs
• Performance Metrics MCQs
  • Clock Speed and Cycles per Instruction (CPI) MCQs
  • MIPS (Million Instructions per Second) MCQs
  • FLOPS (Floating-Point Operations per Second) MCQs
  • Amdahl’s Law MCQs
• Parallelism in Computer Architecture MCQs
  • Instruction-Level Parallelism (ILP) MCQs
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  • Thread-Level Parallelism (TLP) MCQs
  • Symmetric Multiprocessing (SMP) vs Asymmetric Multiprocessing (AMP) MCQs
• Multicore and Multiprocessor Systems MCQs
  • Multicore Architectures MCQs
  • Shared Memory vs Distributed Memory MCQs
  • Interconnection Networks MCQs
• Control Unit Design MCQs
  • Hardwired Control vs Microprogrammed Control MCQs
  • Control Signals and Timing MCQs
  • Instruction Cycle and Control Flow MCQs
• Pipeline Hazards MCQs
  • Structural, Data, and Control Hazards MCQs
  • Techniques to Overcome Hazards (Stalling, Forwarding, Branch Prediction) MCQs
• Branch Prediction and Speculation MCQs
  • Static and Dynamic Branch Prediction MCQs
  • Speculative Execution MCQs
  • Branch Target Buffers MCQs
• Arithmetic and Logic Operations MCQs
  • Integer and Floating-Point Arithmetic MCQs
  • ALU Design MCQs
  • Fixed-Point vs Floating-Point Representation MCQs
• Memory Management MCQs
  • Paging, Segmentation, and Virtual Memory MCQs
  • Memory Protection and Privilege Levels MCQs
  • Memory Allocation and Deallocation MCQs
• Power and Energy Efficiency MCQs
  • Power Dissipation in CPUs MCQs
  • Low-Power Design Techniques MCQs
  • Energy-Aware Computing MCQs
• Advanced Topics MCQs
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• Emerging Trends
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