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Index > Macroinstructions > macro to detect empty sections

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daluca



Joined: 05 Nov 2005
Posts: 86
daluca
any idea of how can i detect if a section is empty?

specificaly i would like to generate data and code sections when the preprocesor finds _TEXT _DATA and _BSS macros but not to gerate a section
if this macros are not folowed by data or code like:

Code:

_BSS    segment dword public use32 'BSS'
        align   4
smgnlfeia       label   dword
        db      128     dup(?)

    


this will be expanded to:
Code:
         
section '.bss' readable writeable
           align   4
smgnlfeia:  db 128 dup(?)

    


but this:

Code:

_BSS    segment dword public use32 'BSS'
_BSS    ends 

    


will be ignored.

I'm working in an include file that will make asm files (generated by the borland freecommandline C compiler) "assemblyables" by fasm

I allready have assembled some files but i want to remove the empty sections.

thanks.
Post 01 Jan 2008, 18:47
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17284
Location: In your JS exploiting you and your system
revolution
In most cases an empty section tells the loader to allocate uninitialisesd memory for things like stacks (your BSS example). In a PE file this simply means one extra entry in the header of 40 bytes.

However since you want to remove the sections then I would suggest a 'section' structure (struc is a special macro that can take a label as a parameter). Then you also need an 'ends' macro which will detect the length of the section and act accordingly.
Post 02 Jan 2008, 01:54
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