Pir Mehr Ali Shah
Arid Agriculture University, Rawalpindi
Office of the controller of Examinations
Mid Exam / Spring 2020 (Paper Duration 48 hours)
To be filled by Teacher
Course No.: …..CS-530……Course Title: …Computer Organization & Assembly Language…
Total Marks:…………48……… Date of Exam:………………23-June-2020……………………..
Degree: …………… BS(CS)……………...Semester:…6th … Section:………C (Morning)……...
7
8
9
10
__ __ __
Marks
Obtained
Total Marks in Words:
Name of the teacher: Mr. Muhammad Usman
Who taught the course:
__
__
___
Q. No.
1
2
3
4
5
6
Marks
Obtained/
Total Marks
_ _ /48 = _ _ /12
Signature of teacher / Examiner:
To be filled by Student
Registration No.: …………………………… Name:……………………………………………….
Note:
1. Approximately paper solving time is 2.5 hrs, however submission time is till 48 hours.
2. Try to upload paper as soon as possible to avoid DOS error at server due to bulk submissions
in late hours.
3. There are total four (4) questions in the paper.
4. Write programs in DOSBOX / emu8086 and add code with screenshots of program with its
output in your answer sheet (word file) wherever required.
5. Make sure you have filled your Name and Reg. No. in the above provided space.
6. Upload the paper only through PC or laptop, Mobile submission is not allowed.
Answer the following questions.
Question # 1:
(Points: 3+3+6=12)
a) Describe the following resister with their purposes.
1) Code Segment
2) Flag Registers
3) Extra Segment
4) Base Register
5) Accumulator
b) Describe the difference between
1) Instruction Pointer
2) Stack Pointer
3) Base pointer
c) Write a code to display the largest number in array. Array size is up to 5 elements.
OR
Sample execution:
Write a code to convert Capital letter to small letter and then display
A=a
all Capital letter (A to Z) along with Small letter (a to z) on the next
B=b
line.
……
Z=z
Solution of Question # 1:
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Question # 2:
(Points: 2+4+6=12)
a) Find the following differences using twos complement arithmetic:
1) Binary of your last 3 digits of ARID number (i.e. 449 111000001) – 11011010
2) Binary of your last 4 digits of ARID number (i.e. 2449 1001…) – 1111100111
b) The hypothetical machine has two I/O instructions:
0011 Load AC from I/O
0111 Store AC to I/O
In these cases, the 12-bit address identifies a particular I/O device. Show the program
execution (using the format of Figure 1 and filled Figure 2) for the following program:
Take a mod of your last 4 digit of your arid number with 10 (e.g. if arid no. is 18-arid1234 then take mod of 1234 % 10 = 4)
1. Load AC from device 4 (mod result).
2. Add contents of memory location 940/941.
(940 if mod result is even, 941 if mod result is odd)
3. Store AC to memory location 940/941.
(940 if mod result is odd, 941 if mod result is even)
Assume that the next value retrieved from device 4 (mod result) is last two digits of
arid number and that location 940/941 contains a value of 3.
Figure 1
Figure 2
c) Convert the following high level (C++) program into assembly language.
#include<iostream>
using namespace std;
int main()
{
char name;
int age;
cout<<"Enter Full name: ";
cin>>name;
cout<<"Enter age: ";
cin>>age;
cout<<"\nDisplaying Info."<<endl;
cout<<"Name: "<<name<<endl;
cout<<"Age: "<<age<<endl;
}
Solution of Question # 2:
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Question # 3:
(Points: 2+4+6=12)
a) When Two 16-bits numbers are multiplied, what two registers holds the product? Show
the registers that contains the most and least significant portions of the products.
b) Write an if-else statement in assembly language that displays Yes if a variable age is
greater than 21 or otherwise displays No.
c) Predict the output of the following code and comments every-line purpose.
.model small
.stack 100h
.code
start:
mov cx, 5
L1:
push cx
L2:
mov ah,2h
mov dl,2Ah
int 21h
loop L2
mov dl,0Ah
int 21h
mov dl,0Dh
int 21h
pop cx
loop L1
mov cx,5
L3:
push cx
L4:
mov ah,2h
mov dl,20h
int 21h
loop L4
mov dl,2Ah
int 21h
mov dl,0Ah
int 21h
mov dl,0Dh
int 21h
pop cx
loop L3
exit:
int 21h
end start
Solution of Question # 3:
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Question # 4:
(Points: 2+4+6=12)
a) Explain what the JMP AX Instruction accomplishes. Also identify it as a near or far
jump instruction.
b) If AX=8FFF and BX=0FFF and “cmp ax, bx” is executed, which of the following jumps
will be taken? Each part is independent of others. Also give the value of Z, S, and C
flags.
1) jg greater
2) jl smaller
3) ja above
c) Write a program that prompts the user to type a decimal number of 16 digits or less,
display its output in Hex on the next line. If the user enters an any wrong character, he
or she should be prompted to begin again.
Solution of Question # 4:
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
