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Index > Windows > MessageBox without macros [MASM > FASM]

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Izu1



Joined: 15 Feb 2010
Posts: 4
Izu1
Hello everyone, can somebody show how to convert this to fasm? I read that offsets are don't exist in fasm, so how would you pass string as an argument?

Code:
      jmp @F
      szDlgTitle    db "Minimum MASM",0
      szMsg         db "  --- Assembler Pure and Simple ---  ",0
    @@:

    push MB_OK
    push offset szDlgTitle
    push offset szMsg
    push 0
    call MessageBox
    


thanks for help.
Post 15 Feb 2010, 12:01
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
in FASM, name of label always stands for offset. Eg. if "szMsg" is at offset 403020, then "mov eax, szMsg" means "mov eax, 403020", and "mov eax, [szMsg]" means "mov eax, [403020]". First moves offset, second moves value at offset. BTW, this is same in NASM.
Post 15 Feb 2010, 12:31
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Izu1



Joined: 15 Feb 2010
Posts: 4
Izu1
This still doesnt compile, says write failed.
Code:
  
    push MB_OK
    push szDlgTitle
    push szMsg
    push 0
    call [MessageBox]
    
Post 15 Feb 2010, 12:40
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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
Hi Izu1,

Perhaps an instance of the application keep running in the background?
Post 15 Feb 2010, 12:48
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
Write failed means the output file can't be (re)written. You probably didn't finish your application, and it is still running (so the EXE file is locked and can't be overwritten by FASM). Hit CTRL+ALT+DEL and kill it.
Post 15 Feb 2010, 13:17
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Izu1



Joined: 15 Feb 2010
Posts: 4
Izu1
Yes seems like the process did not terminate properly... Laughing by the way should I adjust the stack after pushing parameters on it? or is it adjusted by api when it returns?
Post 15 Feb 2010, 13:51
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17279
Location: In your JS exploiting you and your system
revolution
Standard call (stdcall) spec says that the stack is adjusted by the callee. So you don't have to adjust it.
Post 15 Feb 2010, 13:56
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Izu1



Joined: 15 Feb 2010
Posts: 4
Izu1
thanks for help everyone, I'm still kind of new to assembler programming and completely new to fasm.
Post 15 Feb 2010, 14:21
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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
Hi everyone,

Why this code output is 321 in MASM and 123 in FASM?

Code:
.686
.model flat, stdcall

include \masm32\include\windows.inc
include \masm32\include\kernel32.inc
include \masm32\include\user32.inc
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\user32.lib

.data
    msg  dd 0,0

.code
main:
       mov [msg], "123"
  invoke MessageBox, 0,  ADDR msg,  0, 0
      invoke ExitProcess, 0
end main
    


Code:
    format pe console 4.0
    include 'win32ax.inc'

.data
    msg  dd 0,0

.code
main:
    mov [msg], "123"
    invoke MessageBox, 0, addr msg,  0, 0
    invoke ExitProcess, 0
.end main
    
Post 29 Apr 2010, 20:38
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
See fasm's FAQ, third question.
Post 29 Apr 2010, 20:55
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Picnic



Joined: 05 May 2007
Posts: 1288
Location: behind the arc
Picnic
Thanks for response Tomasz Grysztar.
Post 29 Apr 2010, 21:16
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