Download Binary Coded Decimal - Computer Architecture - Past Exam and more Exams Computer Architecture and Organization in PDF only on Docsity!
Cork Institute of Technology
Bachelor of Science (Honours) in Software Development and Computer
Networking – Stage 1
(NFQ Level 8)
Summer 2006
Computer Architecture
(Time: 3 Hours)
Answer any five questions. Examiners: Mr. S. Lankford Mr. J. Buckley Dr. A. Kinsella
Q1. (a) Convert the Decimal value, 468 10 , into Binary Coded Decimal (BCD). [2 marks] (b) i. Convert the following from Binary to Hex 0111001011012 [2marks] ii. Convert the following from Octal to Hex 67438 [2 marks] (c) Given n bits , what is the range of numbers, which can be represented by the following: i. An unsigned binary number system [2 marks] ii. A two’s complement number system [2 marks] (d) Determine the Hamming code for the information bits, 1101 2 , using ODD parity. [5 marks] (e) Assume the following 32-bit floating-point representation:
sign bit of mantissa
8 bit exponent in two’s complement
23 bit mantissa
Using this format, code the following value in floating point format: i. -8.25 [5 marks]
Q2. (a) Draw the K-map for the following expression. Using the rules of K-maps, simplify the expression:
ABCD + ABCD + ABCD + ABCD_ [4 marks]
(b) Using a Sum of Products approach, design the circuit for the following truth table. In your design, show the Boolean expression for the truth table and the corresponding circuit.
A B C F (Output) 0 0 0 1 0 0 1 0 0 1 0 1 0 1 1 0 1 0 0 1 1 0 1 0 1 1 0 0 1 1 1 1 [6 marks]
(c) Draw the circuit and truth table for: i. A Half Adder [3 marks]
(d) Using black box design, draw the following: i. A Full Adder using Half Adders and any other gates. [3 marks] ii. A 3-bit Carry Ripple Adder using Full Adders. [4 marks]
Q4. (a) Describe the sequence of steps in involved in the fetch and execute cycle in a 68000 based microprocessor. [8 marks]
(b) What types of addressing modes are used in the following instructions? Explain what happens to the specified operands once each instruction executes.
i. MOVEA #2,(A1) ii. MOVEA #4,(A2)+ iii. MOVEA #9,-(A0) iv. MOVE #5,D [4 marks]
(c) Write an assembly language program, which determines the odd numbers stored in the array, which is outlined below. The array is terminated with the value 01. Include code, which checks if the end of the array has been reached.
Each odd number found is to be stored in a separate array, which you must define.
INPUT: DC.B 08,07,43,05,01 [8 marks]
Q5. (a) Describe, briefly, the function of the following in the 68000 microprocessor: i. PC ii. IR iii. SR iv. Control Unit v. ALU [10 marks]
(b) What is wrong with the following assembly language statements?
i. MOVE.B D3,# ii. ADD.B (A8)+,D iii. CLR.L -(D1) [3 marks]
(c) Write a 68000 assembly language program, which calculates the average of 10 numbers stored in the array, MYNUMS. The result, i.e. the average of the numbers, should be stored in register D0. Define your array to hold 10 numbers. Use some form of indirect addressing to access the elements within the array. [7 marks]
Q6. (a) Briefly describe what is meant by DRAM and SRAM. In your explanation outline the key features and characteristics associated with each type of RAM. [8 marks]
(b) What is the front side bus speed and theoretical transfer rates of the following DDR SDRAM? Show how you arrived at the theoretical transfer rates of each type of DDR SDRAM. i. PC 1600 DDR 200 ii. PC 2700 DDR 333 [4 marks]
(c) Explain and illustrate what is meant by the “Hierarchy of Memory”. In your explanation, give a rough indication of typical access speeds, required to access the various types of memory in the hierarchy. [8 marks]
