# CS401 Assignment 2 Solution and Discussion

Computer Architecture and Assembly Language Programming (CS401)
Assignment # 02
Total marks = 20

Nov 26, 2019

RULES FOR MARKING
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• The assignment is submitted after the due date.
• The submitted assignment does not open or file is corrupt.
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Topic Covered:
• Branching
• Subroutines•
NOTE
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If you people find any mistake or confusion in assignment (Question statement), please consult with your instructor before the deadline. After the deadline no queries will be entertained in this regard.
For any query, feel free to email at:
[email protected]

Q1. Write a subroutine that will find the first even number from an array of your VU ID and calculate its factorial. (10 Marks)

Note: Skip 0’s in your VU ID as shown below,
VU ID: BC190206435
After skipping 0’s, array would be:
Array: 1, 9, 2, 6, 4, 3, 5
The first even number is 2 in the array so its factorial will be calculated and saved in AX register.

Q2. Write a code in assembly language (using appropriate jumps) equivalent to this given code in C. (10 Marks)

``````#include <stdio.h>
int main()
{
int n1=1, n2=2;
int largest;
if( n1>n2)
largest=n1;
else
largest = n2;
return 0;
}
``````

“The End”

Q1. Write a subroutine that will find the first even number from an array of your VU ID and calculate its factorial. (10 Marks)

Note: Skip 0’s in your VU ID as shown below,
VU ID: BC190206435
After skipping 0’s, array would be:
Array: 1, 9, 2, 6, 4, 3, 5
The first even number is 2 in the array so its factorial will be calculated and saved in AX register.
Solution:

``````[org 0x100]
jmp start
data:  dw 1, 9,2,6,4,3,5

;initiliazation

checkEven:
mov dl,0002h
mov ax,[data+bx]
mov cx,[data+bx]
xor ah,ah
xor ch,ch
div dl
cmp ah,00h    ;checking remainder
je fact
jmp checkEven
fact:
mov ax,0001
mov dx,0000
mult:
mul cx
loop mult

ret

start:  mov si,00h
mov bx,si
call checkEven

mov ax,0x4c00
int 0x21
``````

Q2. Write a code in assembly language (using appropriate jumps) equivalent to this given code in C. (10 Marks)
#include <stdio.h>
int main()
{
int n1=1, n2=2;
int largest;
if( n1>n2)
largest=n1;
else
largest = n2;
return 0;
}

Solution:

Assembly code:

``````[org 0x100]
jmp start
n1 db 1
n2 db 2
largest db 0

start:
mov ax, [n1]
xor ah,ah
mov bx, [n2]
cmp ax,bx
ja large
mov [largest],bx

large:  mov [largest],ax

mov ax, 0x4c00
int 21h
``````

Q1. Write a subroutine that will find the first even number from an array of your VU ID and calculate its factorial. (10 Marks)

Note: Skip 0’s in your VU ID as shown below,
VU ID: BC190206435
After skipping 0’s, array would be:
Array: 1, 9, 2, 6, 4, 3, 5
The first even number is 2 in the array so its factorial will be calculated and saved in AX register.
Solution:

``````[org 0x100]
jmp start
data:  dw 1, 9,2,6,4,3,5

;initiliazation

checkEven:
mov dl,0002h
mov ax,[data+bx]
mov cx,[data+bx]
xor ah,ah
xor ch,ch
div dl
cmp ah,00h    ;checking remainder
je fact
jmp checkEven
fact:
mov ax,0001
mov dx,0000
mult:
mul cx
loop mult

ret

start:  mov si,00h
mov bx,si
call checkEven

mov ax,0x4c00
int 0x21
``````

Q2. Write a code in assembly language (using appropriate jumps) equivalent to this given code in C. (10 Marks)
#include <stdio.h>
int main()
{
int n1=1, n2=2;
int largest;
if( n1>n2)
largest=n1;
else
largest = n2;
return 0;
}

Solution:

Assembly code:

``````[org 0x100]
jmp start
n1 db 1
n2 db 2
largest db 0

start:
mov ax, [n1]
xor ah,ah
mov bx, [n2]
cmp ax,bx
ja large
mov [largest],bx

large:  mov [largest],ax

mov ax, 0x4c00
int 21h
``````