Philadelphia University
Lecturer
: Dr. M. Maouche
Coordinator
: Dr M. Maouche
Internal Examiner : Prof.Dr. M. Mahafzah
Faculty of Information Technology
Department of Computer Science
Examination Paper
Course Name: Computer Design and Organization (750233)
Section: 1
Final Exam
First Semester Academic Year: 2014/15 Date: February, 4th, 2015 Time: 120 minutes
Information for Candidates
1.This examination paper contains 5 questions, totaling 42 marks (bonus: 2 marks)
2.The marks for parts of questions are shown in round brackets.
Advice to Candidates
1. You should write your answers precisely, clearly and to the point .
I. Basic Notions
Objectives. The aim of the question in this part is to evaluate the required minimal student
knowledge and skills. Answers in the pass category represent the minimum acceptable standard.
Question1: (14 marks)
1. Name two number representation techniques that deal with Fractional
numbers.
(2 marks)
2. Categorize ISAs according to the operand location criteria.
(3 marks)
3. Draw four different kinds of ISA instruction Formats.
(4 marks)
4. Name at least three categories of ISA instructions types.
(3 marks)
5. Write the benefits of ISA based on expanded operation codes.
(2 marks)
II. Familiar Problems Solving
Objectives. The aim of the question in this part is to evaluate that the student has some basic
knowledge of the key aspects of the lecture material and can attempt to solve familiar
problems.
Question2: (5 marks)
Given the following two binary numbers: 11111100 and 01110000.
a. Which of these two numbers is the larger unsigned binary number? (2 marks)
b. Which of these two numbers is the larger when it is being interpreted on a
computer using signed-two’s complement representation?
(3marks)
Explain your answers.
Question3: (8 marks)
The memory unit of a computer has 256K words of 32 bits each. The computer has an
Instruction format with 4 fields: an opcode field; a mode field to specify 1 of 7
addressing modes; a register address field to specify one of 60 registers; and a
memory address field. Assume an instruction is 32 bits long.
Answer the following:
a. How large must the mode field be? (2 marks)
b. How large must the register field be? (2 marks)
c. How large must the address field be? (2 marks)
d. How large is the opcode field?
(2 marks)
Question 4: (6 marks)
Suppose we have the instruction Load 500. Given memory and register R1 contain
the values below:
Assuming R1 is implied in the indexed addressing mode, determine the actual value
loaded into the accumulator and fill in the table below:
III. Unfamiliar Problems Solving
Objectives. The aim of the question in this part is to evaluate that the student has some basic
knowledge of the key aspects of the lecture material and can attempt to solve unfamiliar
problems.
Question 5: (9 marks)
Write code to implement the expression: A= (B + C) * (D + E)
on 3-, 2-, and 1- address machines. In accordance with programming language
practice, computing the expression should not change the values of its operands.