am developing an assembly language program that will check whether an inputted number is divisible by 3 or not, now I am struggling to get things correct but my code is running..and it seems like dx register always have content zero even after div has been executed..
org 100h
jmp main
msg_prpt: db 'Enter a number (1-9): $'
msg_err: db 0dh, 0ah, 'Number out of range. $'
msg_1: db 0dh, 0ah, 'Number is divisible by 3. $'
msg_2: db 0dh, 0ah, 'Number is not divisible by 3. $'
num: db ?
num1 dw ?
display:
mov ah, 9h ; "display string" function for int 21h
int 21h
ret
dsp_prpt:
mov dx, msg_prpt ; copy contents of msg_prompt to dx
call display
ret
dsp_err:
mov dx, msg_err ; copy contents of msg_err to dx
call display
ret
get_num:
mov ah, 1h ; "character input" function for int 21h (stored in al)
int 21h
mov [num], al ; copy contents of al to space at address [num]
mov num1,num
ret
;checking if the inputted number is divisible by 3
validateDivisibleby3:
mov dx,0
mov ax,num ; copy character to ax for comparison
mov bx,03h
idiv bx
cmp dx,0
je isMultipleof3:
call isNotMultipleof3
ret
convert:
sub al, 30h ; subtract 30h from input to get numeric from ascii
ret
isMultipleof3:
; print the result:
mov dx, msg_1 ; copy contents of msg_prompt to dx
call display
ret
isNotMultipleof3:
; print the result:
mov dx, msg_2 ; copy contents of msg_prompt to dx
call display
ret
exit:
; wait for any key press:
mov ah, 0
int 16h
ret ; return control to operating system.
main:
call dsp_prpt
call get_num
call validateDivisibleby3
call convert
call exitI will really appreciate your help..
