CACS155 Microprocessor and Computer Architecture

Microprocessor and Computer Architecture TU Board 2026 question paper

10 questionsSit this paper (timed)

Tribhuvan University

Bachelor of Computer Application

Semester 2 · TU Board 2026

Course Title: Microprocessor and Computer Architecture (CACS155)

Full Marks: 60Pass Marks: 24Time: 3 hours

Candidates are required to answer the question in their own words as far as possible.

Group B

Attempt any SIX question.(6 × 5 = 30)

  1. 2.

    Explain the internal architecture of the 8085 microprocessor. Describe the functions of the ALU, accumulator, general-purpose registers, program counter, stack pointer, instruction register, and control unit.

    5
  2. 3.

    Explain the different addressing modes of the 8085 microprocessor with suitable instruction examples.

    5
  3. 4.

    Differentiate between RISC and CISC architectures on the basis of instruction set, instruction format, execution time, addressing modes, hardware complexity, and pipelining.

    5
  4. 5.

    Explain the concept of Direct Memory Access (DMA). Describe the steps involved when a DMA controller transfers a block of data between an I/O device and memory.

    5
  5. 6.

    Explain arithmetic, logical, and shift micro-operations with suitable examples. Also state the purpose of each type of micro-operation.

    5
  6. 7.

    Compare hardwired and microprogrammed control units in terms of implementation, speed, flexibility, complexity, and modification of the instruction set.

    5
  7. 8.

    Explain instruction pipelining. Discuss structural hazards, data hazards, and control hazards, and describe suitable techniques used to reduce these pipeline hazards.

    5

Group C

Attempt any TWO questions(2 × 10 = 20)

  1. 9.

    Answer the following: a. Explain the instruction cycle, machine cycle, and T-state in the 8085 microprocessor. Describe the sequence of operations performed while executing the instruction MVI A, 32H. [6.5] b. Write an 8085 assembly language program to search an array of eight unsigned numbers and store the smallest number at a specified memory location. [6]

    10
  2. 10.

    Answer the following: a. Explain the stored-program concept and describe how the CPU, memory, input unit, and output unit communicate through address, data, and control buses. [6.5] b. Explain Booth's multiplication algorithm. Using the algorithm, demonstrate the multiplication of binary numbers (+5) and (−3). [6]

    10
  3. 11.

    Answer the following: a. Explain the memory hierarchy of a computer system. Discuss registers, cache memory, main memory, and secondary memory in terms of speed, capacity, cost, and access time. Also explain the concept of memory address mapping. [6.5] b. Explain the major components of the 8086 microprocessor. Discuss the functions of the Bus Interface Unit, Execution Unit, segment registers, instruction pointer, general-purpose registers, and instruction queue. [6] OR Compare isolated I/O and memory-mapped I/O in terms of address space, instructions used, control signals, available I/O addresses, and system complexity with suitable examples.

    10

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