CODEWITHSUNDEEP
assemblyinputbiosemu8086
Ihtisham Arif
Ihtisham Arif

Reputation: 63

Assembly : Input value from user (more then one input)

This is a function in assembly to take input from the user in 2 strings "size" and "per",
but it only takes 1 input and then starts crashing.

I need help. Thank you in advance.

input:
mov si,0
lb :
mov ah,0
int 16h
cmp al,0x0d
je 2nd
mov [size + si],al
inc si
loop lb
2nd:
mov si,0
lb1:
mov ah,0
int 16h
mov [per + si],al
cmp al,0x0d
je 3rd
inc si
loop lb1
3rd:
ret

Upvotes: 1

Views: 1057

Answers (1)

Sep Roland
Sep Roland

Reputation: 39166

To create a loop it's not mandatory to use the loop instruction!

In your 1st loop, after storing the character in size and after incrementing the pointer in SI, you need to always jump back to the top of your loop. The correct instruction then is jmp lb, an unconditional jump to the label lb.

input:
    mov si, 0
lb :
    mov ah, 0
    int 16h
    cmp al, 0x0d
    je  2nd
    mov [size + si], al
    inc si
    jmp lb              ; The unconditional jump
2nd:

In your 2nd loop, after incrementing the pointer in SI, you need to always jump back to the top of this loop. The correct instruction then is jmp lb1, an unconditional jump to the label lb1.

    mov si, 0
lb1:
    mov ah, 0
    int 16h
    mov [per + si], al
    cmp al, 0x0d
    je  3rd
    inc si
    jmp lb1             ; The unconditional jump
3rd:
    ret

One thing that you should be aware of is where you check for the ENTER key (ASCII 13):

  • The 1st loop checks it before storing in memory and thus no carriage return is attached to the string size.
  • The 2nd loop checks it after storing in memory and thus a carriage return is attached to the string per.

This difference is probably not what you expect.

Upvotes: 1

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