CS401 GDB 1 Solution and Discussion

[zareen]

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

Deadline Date
Nov 26, 2019

Please carefully read the following instructions before attempting assignment.
RULES FOR MARKING
It should be clear that your assignment would not get any credit if:
• The assignment is submitted after the due date.
• The submitted assignment does not open or file is corrupt.
• Strict action will be taken if submitted solution is copied from any other student or from the internet.
You should concern the recommended books to clarify your concepts as handouts are not sufficient.
You are supposed to submit your assignment in .doc or docx format.
Any other formats like scan images, PDF, zip, rar, ppt and bmp etc. will not be accepted.
Topic Covered:
• Addressing Modes
• Branching
• Subroutines•
NOTE
No assignment will be accepted after the due date via email in any case (whether it is the case of load shedding or internet malfunctioning etc.). Hence refrain from uploading assignment in the last hour of deadline. It is recommended to upload solution file at least two days before its closing date.
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:
cs401@vu.edu.pk

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”

[zareen]

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
        add bx,2
        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

[zareen]

https://www.youtube.com/watch?v=hUTxoD74RJ8

[zareen]

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
        add bx,2
        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