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Index > Macroinstructions > [BUG]bug in "IF.inc"?

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alorent



Joined: 05 Dec 2005
Posts: 221
alorent 09 Feb 2010, 12:47
Hello guys,

Please, look at this code:

Code:


include 'win32ax.inc' 
include 'macro\if.inc'

.data

p1 db 0

.code

  start:

       lea     eax, [p1]         ; [eax] = 0

   .if ~(byte [eax])

               db 0cch

 .endif


      .if ~byte [eax]

         db 0cch

 .endif


      invoke  MessageBox,HWND_DESKTOP,"Hi! I'm the example program!",invoke GetCommandLine,MB_OK
       invoke  ExitProcess,0

.end start
    


The second ".if" is processed correctly so, the "db 0cch" is *executed*.

But the first ".if" does *not* execute the "db 0cch"!!!

So, it seems that the parenthesis are messing all out?

Thanks!
Post 09 Feb 2010, 12:47
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20356
Location: In your JS exploiting you and your system
revolution 09 Feb 2010, 12:52
Compiles to:
Code:
00402006    8038 00         cmp     byte[eax],0
00402009    74 01           jz      0x0040200c
0040200b    cc              int3
0040200c    8038 00         cmp     byte[eax],0
0040200f    75 01           jnz     0x00402012
00402011    cc              int3    
Bug confirmed.
Post 09 Feb 2010, 12:52
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alorent



Joined: 05 Dec 2005
Posts: 221
alorent 09 Feb 2010, 21:38
Thanks revolution for confirming the bug.

Is the bug related to the "IF.INC" file or a fasm bug?

Thanks!
Post 09 Feb 2010, 21:38
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20356
Location: In your JS exploiting you and your system
revolution 10 Feb 2010, 01:35
This is related to the 'if.inc' macro file. Not to the fasm core assembler. But still definitely needs fixing.
Post 10 Feb 2010, 01:35
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr 10 Feb 2010, 08:58
alorent,

You're right, this bug is related to parentheses handling in PARSECOND macro. Negation was added twice, before and after opening parenthesis. This should fix it:
Code:
      match (,symb                      ; 134
      \\\{                              ; 135
          parsed equ parsed neg@cond,<  ; 136
          define neg@cond               ; ADDED
          define nest@cond +            ; 137
          define symb@cond              ; 138
      \\\}                              ; 139    
Post 10 Feb 2010, 08:58
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20356
Location: In your JS exploiting you and your system
revolution 10 Feb 2010, 09:03
With baldr's fix: now compiles to:
Code:
00402006    8038 00         cmp     byte[eax],0
00402009    75 01           jnz     0x0040200c
0040200b    cc              int3
0040200c    8038 00         cmp     byte[eax],0
0040200f    75 01           jnz     0x00402012
00402011    cc              int3    
Fix confirmed.
Post 10 Feb 2010, 09:03
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alorent



Joined: 05 Dec 2005
Posts: 221
alorent 10 Feb 2010, 11:13
Thanks baldr!!!

Great work!!! Very Happy
Post 10 Feb 2010, 11:13
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland
Tomasz Grysztar 10 Feb 2010, 16:19
I included the fix in the latest 1.69.12 package.
Post 10 Feb 2010, 16:19
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DOS386



Joined: 08 Dec 2006
Posts: 1903
DOS386 14 Feb 2010, 14:22
Tomasz Grysztar wrote:
I included the fix in the latest 1.69.12 package.


COOL Smile 1.69.12 is out and announcement is hidden in the Macroinstructions subforum. Could you please look into this bug for 1.69.13 ?
Post 14 Feb 2010, 14:22
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