Computer Architecture and Organization

SECTION A

Question 1 (20 marks)

Compulsory to show each step clearly.

a) Giving 0342302, illustrate the subtraction of the 3th digit of the number

from the 5th digit of number in the 2’s complement form using 8 bits.

(6 marks)

b) Calculate the decimal equivalent of the hexadecimal number DEF.

(3 marks)

c) Identify the subtraction of C675 – A247 in 2s complement form.

(3 marks)

d) A 9 bit binary is given to you. Distinguish the below and explain your answers in detail. Your

answer must be in both binary and decimal.

(8 marks)

i. The most +ve number in signed form using two’s complement.

ii. The most –ve number in signed form using two’s complement.

iii. The most –ve number represented in unsigned number.

iv. The most + ve number represented in unsigned number.

Question 2 (20marks)

a) Assume that the machine is starting with its program counter containing the address 20. This

machine’s instructions are described in language description table.

Display the machine cycle in the table form with Program Counter (P.C), increment of P.C.,

Instruction Register (I.R.) and General-Purpose Register (G.P.R) and description of each

instruction executed. Explanation of each of the output is compulsory.

b) Assume that the machine is starting with its program counter containing 00. This machine’s

instructions are described in language description table. Display the machine cycle in the table

form with Program Counter (P.C), increment of P.C., Instruction Register (I.R.) and GeneralPurpose Register (G.P.R) and description of each instruction executed. Show SIX (6) execution

process. Explanation of each of the output is compulsory.

Question 3 (9 marks)

Use Karnaugh map to simplify the expressions below:

a) 𝑦 = 𝐶̅(A’B’D’ + 𝐷) + 𝐴𝐵’𝐶 + D’

(5 marks)

b) 𝐹 = 𝐴’B’C’+ ABC’+A’C’

(4 marks)

Question 4 (6 marks)

Apply the Boolean theories to simplify the expressions below. Show the Boolean theorem for each

step.

a) X= (𝐴 + 𝐵)(𝐴’+ 𝐶 )(𝐵 + 𝐶) (3 marks)

b) Y= (B + C’)(B’ + C)(A’+B+C’)’ (3 marks)

Question 5 (5 marks)

Design a circuit that produces a HIGH output only when all three inputs are the same level.

(5 marks)

SECTION B

Short Answer Questions – 40 marks

Question 6 (30 marks)

a) The battle between digital and analog signal transmission never ends.

” Produces fewer error during transmission” and “permits higher transmission rate” are both

advantages of the digital signal. Analyze the reason for these advantages and compare

these factors in analog transmission.

(10 marks)

b) Investigate the relation between pipelining and RISC-Reduced instruction set Computing.

Support your answer with examples. (10 marks)

c) Investigate about the half adder and full adder in detail with the appropriate diagrams and

truth tables.

(10 marks)

Question 7 (10 marks)

Design a circuit with four-bit binary input W, X, Y, Z and a single output (K) with the criteria below:

K= 0, when the input is less than 610

K = 1, otherwise

Determine the inputs and outputs

W is the MSB

Z is the LSB

(10 marks)

Complete Logic Circuit with labels (3m), Incomplete but correct (1-2m)

Complete Truth Table with labels (3m), incomplete but correct (1-2m)

Proving using the K-map (3m)

Follow the five steps (1m)

ASCII Table

Language Description Table