display message many time in Assembly language

Question

I'm trying to display a message several times.

I used nasm and I used this program :

    MOV cx, 1
    mov  ax, 10
re:
    CMP ax, cx
    JS fin
    mov  dx, texte 
    INC cx
    JMP re
fin:
    Int 21h
    texte: db 'Hello, World !!'

What's the problem? (also, it doesn't look like you're initializing `ax`) — obe, Oct 29 '16 at 19:26
The problem tnis code not display the message Hello, World !! 10 times — Saidi Mohamd, Oct 29 '16 at 19:36

score 2 · Answer 1 · answered Oct 29 '16 at 19:54

2

Currently you invoke int 21h only at the bottom. Try to move it into the loop.

Also, it's been a really long time since I last did anything in assembly but you probably also need to prepare some registers to determine what int 21h would do. See more info here: http://spike.scu.edu.au/~barry/interrupts.html#ah09

answered Oct 29 '16 at 19:54

obe

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I change it and I used the nasm command but the message is not displayed. – Saidi Mohamd Oct 29 '16 at 20:01
1

Please don't change the code in your question. Instead, append the updated code below. – fuz Oct 29 '16 at 20:46

Seva Alekseyev · Accepted Answer · 2016-11-01T16:44:58.217

1

Couple more things:

for int21h to perform output, you need to set AH to 9. You're already using AX to store the loop limit; you'd have to use some other register (BX, SI, DI are currently unused), or a hard-coded limit. Also, int21h function 9 changes the value of AL on output - one more reason not to use AX.
The string needs to be terminated with the $ character. That's what int21h/9 expects, not an convention of assembly language in general.
And, like obe said, you want the int 21h command before, not after the "jmp re" line.
At the "fin" label, you might want to quit the program. The sequence for that is: "mov ah, 4ch/int 21h".

edited Nov 01 '16 at 16:44

answered Oct 30 '16 at 01:41

Seva Alekseyev

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Or count CX down from 10, instead of using two registers to loop from 1 to 10. Or put the 10 as an immediate operand for CMP. SI and DI are also unused, IDK why you mentioned BX but not them. – Peter Cordes Oct 30 '16 at 02:07
Many ways to do this. "LOOP re" command would probably be the easiest. – Seva Alekseyev Oct 30 '16 at 02:48
Except that [LOOP is slow](http://stackoverflow.com/questions/35742570/why-is-the-loop-instruction-slow-couldnt-intel-have-implemented-it-efficiently), and not a good habit to teach beginners. They won't find real code that uses it when looking at compiler output, so might as well learn to make loops with cmp/jcc (or dec/jnz). It's simpler just to never mention LOOP in the first place, since it's not useful outside of optimizing for code-size. – Peter Cordes Oct 30 '16 at 02:52

display message many time in Assembly language

2 Answers2