Question

Creat a linux assembly program that asks two scores from the user, specifically, the raw score as the first score and the total score as the second score. Store the digits in the EAX and EBX register, respectively. Given the formula raw score divided by total score times 50 and plus 50. Store the result in a memory location 'res' and finally display the result.

Answer 1

Here is the working code :

bits 32
global start   
extern exit,printf, scanf ; it tells that exit exists even if we won't be defining it
import exit msvcrt.dll ; exit function is defined in msvcrt.dll
import printf msvcrt.dll ; contains important C-runtime specific functions (exit, printf)
import scanf msvcrt.dll ; Data Declaration

segment data use32 class=data public

format_scanf db "%d", 0
format_printf1 db "Enter scores for both Raw and Total Score", 0x0d, 0x0a, 0   
format_printf2 db "The result is = %d", 0x0d, 0x0a, 0

score1 dd 0
score2 dd 0
res dd 0
  
segment code use32 class=code public
start:

push dword format_printf1
call [printf]
add esp, 4*1

push score1
push dword format_scanf
call [scanf]
add esp, 4*2

push score2
push dword format_scanf
call [scanf]
add esp, 4*2

MOV EAX, [score1] ; we have the raw score
MOV EBX, [score2] ; we have the total score

MOV EDX, 0 ; Arithmetic operations start from here
MOV ECX, 50
MUL EBX ; start multiplication by 50, result store in EDX:EAX

DIV ECX ; EDX:EAX is divided by ECX (whose value is 50) and quotient will be in EAX, and the remainder in EDX

ADD EAX, 50

MOV [res], EAX

push dword [res]
push dword format_printf2
call [printf]
add esp, 4*2

; exit(0)
push dword 0
call [exit]