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Mino



Joined: 14 Jan 2018
Posts: 163
Mino 17 Feb 2018, 10:16
Hi, first of all I apologize for asking "a lot" of questions these days, I hope it doesn't bother anyone Smile
So, my question day:
I tried to implement the for loop principle in FASM, here is my code:
Code:
format PE console
include 'C:\Users\mino\Desktop\fasmw172\stdlib.inc' ; contains '.idata'
entry main

section '.data' data readable writeable
        Hi   db "Hello", 10, 0
        inx  dw 1

section '.code' code executable
        main:
                push eax
                mov eax, ecx

        CL0:
                if inx <> 10
                   jmp LC0
                end if


                call [ExitProcess]
        LC0:
                push Hi
                call [printf]
                add [inx], 1
                jmp CL0

My code looks good to me. Besides, he's compiling. However, I must have forgotten something, because during the first iteration, it displays full of times "hello", then crashes.
Maybe it's the if instruction? I don't know about that.
I looked in the doc, but she doesn't seem to mention this kind of "mistake."

Could you help me Very Happy ?
Thank you, and have a good day!

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The best way to predict the future is to invent it.
Post 17 Feb 2018, 10:16
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20430
Location: In your JS exploiting you and your system
revolution 17 Feb 2018, 10:28
if is an assembler directive. And inx is a fixed address that is never 10. So the result from if inx <> 10 is always true, thus the line jmp LC0 is always assembled and executed.

Perhaps you want to use cmp
Code:
  cmp [inx],10
  jb LC0
  call [ExitProcess]
LC0:
Post 17 Feb 2018, 10:28
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fasmnewbie



Joined: 01 Mar 2011
Posts: 555
fasmnewbie 17 Feb 2018, 11:29
call [printf]
add esp,4 ;CDECL stack unwinding
Post 17 Feb 2018, 11:29
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Mino



Joined: 14 Jan 2018
Posts: 163
Mino 17 Feb 2018, 12:05
That's perfect, thank you very much for your help Smile

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Post 17 Feb 2018, 12:05
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