Multiple-Choice Questions on Microprocessors and Computer Architecture of TU IT Adhikrit

 Multiple-Choice Questions on Microprocessors and Computer Architecture

Microprocessor and Bus System of Microprocessor Based System

What is the primary function of the address bus in a microprocessor-based system?

a) Transfers data between CPU and memory

b) Specifies memory or I/O device locations

c) Controls the timing of operations

d) Carries power to peripherals

Answer: b) Specifies memory or I/O device locations

Explanation: The address bus carries the memory address or I/O port number to identify the location for data transfer.

Which bus in a microprocessor system is bidirectional?

a) Address bus

b) Data bus

c) Control bus

d) System bus

Answer: b) Data bus

Explanation: The data bus is bidirectional, allowing data to be transferred to and from the CPU, memory, or I/O devices.

Intel 8085 Microprocessor Architecture, Programming, and Interfacing

How many general-purpose registers are available in the Intel 8085 microprocessor?

a) 4

b) 6

c) 8

d) 10

Answer: b) 6

Explanation: The 8085 has six general-purpose registers: B, C, D, E, H, and L, used for data manipulation and addressing.

Which instruction in 8085 is used to load data into the accumulator from memory?

a) MOV

b) LDA

c) STA

d) MVI

Answer: b) LDA

Explanation: The LDA (Load Accumulator Direct) instruction loads data from a specified memory address into the accumulator.

Intel 8086 Microprocessor Architecture

What is the size of the address bus in the Intel 8086 microprocessor?

a) 16 bits

b) 20 bits

c) 24 bits

d) 32 bits

Answer: b) 20 bits

Explanation: The 8086 has a 20-bit address bus, allowing it to address 1 MB (2^20) of memory.

Which segment register in the 8086 is used for storing the instruction pointer?

a) Data Segment (DS)

b) Code Segment (CS)

c) Stack Segment (SS)

d) Extra Segment (ES)

Answer: b) Code Segment (CS)

Explanation: The Code Segment (CS) register, combined with the Instruction Pointer (IP), points to the next instruction to be executed.

Assembly Language Programming with 8086

What does the MOV AX, BX instruction do in 8086 assembly?

a) Moves data from memory to AX

b) Copies the contents of BX to AX

c) Adds BX to AX

d) Compares AX with BX

Answer: b) Copies the contents of BX to AX

Explanation: The MOV instruction copies data from the source (BX) to the destination (AX) without altering the source.

Which 8086 instruction is used to call a subroutine?

a) JMP

b) CALL

c) RET

d) INT

Answer: b) CALL

Explanation: The CALL instruction transfers control to a subroutine, saving the return address on the stack.

Instruction Set, Instruction Format, and Addressing Modes

Which addressing mode in the 8086 uses a register to hold the memory address?

a) Immediate addressing

b) Direct addressing

c) Register indirect addressing

d) Indexed addressing

Answer: c) Register indirect addressing

Explanation: In register indirect addressing, a register (e.g., BX) holds the memory address of the operand.

How many bytes does the 8086 MOV AX, 1234H instruction occupy?

a) 1 byte

b) 2 bytes

c) 3 bytes

d) 4 bytes

Answer: c) 3 bytes

Explanation: The MOV AX, immediate instruction includes a 1-byte opcode and a 2-byte immediate value, totaling 3 bytes.

Interrupt System in Microprocessors

What is the purpose of an interrupt in a microprocessor?

a) To execute a subroutine automatically

b) To pause the CPU indefinitely

c) To handle external or internal events by suspending the current task

d) To reset the microprocessor

Answer: c) To handle external or internal events by suspending the current task

Explanation: Interrupts allow the CPU to temporarily halt its current execution to handle events like hardware signals or errors.

Which interrupt in the 8085 is non-maskable?

a) INTR

b) RST 5.5

c) TRAP

d) RST 7.5

Answer: c) TRAP

Explanation: The TRAP interrupt in the 8085 is non-maskable, meaning it cannot be disabled and is used for critical events.

Computer Organization and Computer Architecture

What is the primary difference between computer organization and architecture?

a) Architecture deals with hardware design; organization deals with software

b) Architecture defines the structure and behavior; organization deals with implementation

c) Organization defines instruction sets; architecture defines memory

d) Both are identical

Answer: b) Architecture defines the structure and behavior; organization deals with implementation

Explanation: Architecture specifies what the system does (e.g., instruction set), while organization details how it is implemented (e.g., circuits).

Which component is NOT part of computer organization?

a) CPU

b) Memory hierarchy

c) Instruction set design

d) I/O system

Answer: c) Instruction set design

Explanation: Instruction set design is part of computer architecture, while CPU, memory, and I/O systems are aspects of organization.

Instruction Cycle and Machine Cycle, Execution of an Instructio

What is the first step in the instruction cycle of a microprocessor?

a) Decode

b) Fetch

c) Execute

d) Store

Answer: b) Fetch

Explanation: The instruction cycle begins with fetching the instruction from memory, followed by decoding and execution.

How many machine cycles are typically required to execute the 8085 MOV A, B instruction?

a) 1

b) 2

c) 3

d) 4

Answer: a) 1

Explanation: The MOV A, B instruction in 8085 requires one machine cycle (opcode fetch) as it is a register-to-register operation.

CPU Structure and Function, Arithmetic and Logic Unit, Data Representation

What is the primary function of the Arithmetic and Logic Unit (ALU)?

a) Stores data temporarily

b) Performs arithmetic and logical operations

c) Manages I/O operations

d) Controls instruction execution

Answer: b) Performs arithmetic and logical operations

Explanation: The ALU handles operations like addition, subtraction, AND, OR, and comparisons.

Which data representation uses 2’s complement in microprocessors?

a) Floating-point numbers

b) Signed integers

c) Unsigned integers

d) ASCII characters

Answer: b) Signed integers

Explanation: 2’s complement is used to represent signed integers, allowing efficient arithmetic operations.

Control Unit, Hardwired and Microprogrammed Control Unit

What is a characteristic of a hardwired control unit?

a) Uses microinstructions stored in memory

b) Implemented using fixed hardware circuits

c) Easily modifiable for new instructions

d) Slower than microprogrammed control

Answer: b) Implemented using fixed hardware circuits

Explanation: Hardwired control units use fixed logic circuits, making them faster but less flexible than microprogrammed units.

What is the role of a microprogrammed control unit?

a) Executes instructions directly

b) Uses microinstructions to generate control signals

c) Manages memory allocation

d) Performs arithmetic operations

Answer: b) Uses microinstructions to generate control signals

Explanation: A microprogrammed control unit uses microcode stored in control memory to generate control signals for instruction execution.

Memory Devices, Classification, and Hierarchies

Which memory type is fastest in the memory hierarchy?

a) RAM

b) Cache

c) Registers

d) Hard disk

Answer: c) Registers

Explanation: Registers, located inside the CPU, are the fastest memory type due to their proximity and speed.

Which memory is volatile?

a) ROM

b) Flash memory

c) SRAM

d) Hard disk

Answer: c) SRAM

Explanation: SRAM (Static RAM), used in cache, is volatile, losing data when power is off, unlike ROM or flash memory.

Cache Memory and Cache Mapping, Multi-level Cache Memory

Which cache mapping technique allows a block to be placed in any cache line?

a) Direct mapping

b) Associative mapping

c) Set-associative mapping

d) Sector mapping

Answer: b) Associative mapping

Explanation: Associative mapping allows a memory block to be placed in any cache line, offering flexibility but requiring complex hardware.

What is the purpose of multi-level cache memory (e.g., L1, L2, L3)?

a) To increase power consumption

b) To balance speed, size, and cost

c) To replace main memory

d) To store permanent data

Answer: b) To balance speed, size, and cost

Explanation: Multi-level caches (L1, L2, L3) provide a hierarchy where smaller, faster caches (L1) are closer to the CPU, while larger, slower caches (L3) reduce costs.

Von Neumann and Harvard Architecture, RISC & CISC Architecture

What is a key difference between Von Neumann and Harvard architecture?

a) Von Neumann uses separate memory for data and instructions

b) Harvard uses a single memory for data and instructions

c) Harvard uses separate memory for data and instructions

d) Von Neumann has no cache memory

Answer: c) Harvard uses separate memory for data and instructions

Explanation: Harvard architecture separates data and instruction memory, allowing simultaneous access, unlike Von Neumann’s single memory.

Which characteristic is typical of RISC architecture?

a) Complex instructions with variable lengths

b) Simple instructions with fixed lengths

c) High number of addressing modes

d) Large instruction set

Answer: b) Simple instructions with fixed lengths

Explanation: RISC (Reduced Instruction Set Computing) uses simple, fixed-length instructions for faster execution.

Input/Output Organization: I/O Programming, Memory-Mapped I/O, DMA

What is memory-mapped I/O?

a) Using separate I/O instructions for device communication

b) Mapping I/O devices to memory addresses

c) Transferring data directly to the CPU

d) Storing I/O data in cache

Answer: b) Mapping I/O devices to memory addresses

Explanation: Memory-mapped I/O allows devices to be accessed as if they were memory locations, using standard memory instructions.

What is the primary advantage of Direct Memory Access (DMA)?

a) Increases CPU workload

b) Allows direct data transfer between memory and I/O devices

c) Reduces memory size

d) Simplifies instruction sets

Answer: b) Allows direct data transfer between memory and I/O devices

Explanation: DMA enables data transfer without CPU intervention, improving efficiency for large data transfers.

Pipelining, Pipelining Hazards, and Remedies

What is a data hazard in pipelining?

a) When an instruction depends on the result of a previous instruction

b) When the pipeline is stalled due to a branch instruction

c) When the CPU runs out of memory

d) When instructions are executed sequentially

Answer: a) When an instruction depends on the result of a previous instruction

Explanation: A data hazard occurs when an instruction needs data that a prior instruction has not yet produced.

Which technique is used to resolve a control hazard in pipelining?

a) Data forwarding

b) Branch prediction

c) Cache replacement

d) Instruction prefetching

Answer: b) Branch prediction

Explanation: Branch prediction anticipates the outcome of branch instructions to minimize pipeline stalls caused by control hazards.