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Index > Windows > pass arguments by stack

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dadius



Joined: 31 Jul 2011
Posts: 2
dadius
hello i have my function

proc aFunction, FileName:BYTE, FileName2:BYTE, ParameterCount:DWORD, ...

do somthing

endp


the ... defines a variable length of parameter when i call function now i do as:


stdcall dword CallFunction, arg1, arg2, 2, param1, param2

instead of passing it this way is there a way to define proc function that i can pass arguments on stack reverse order like:

push param2
push param1
..
call function

thx for help
Post 31 Jul 2011, 20:53
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
Hi, welcome to the board

Is that what you really want? "stdcall dword [func]" and "invoke func", already push the parameters in reverse order (and of course procedures/functions defined with the "proc" macro do expect such order in the stack)
Post 31 Jul 2011, 21:51
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dadius



Joined: 31 Jul 2011
Posts: 2
dadius
my problem is i have big code in which i already pushed arguments in nearly all functions i wanna make it compatible
Post 31 Jul 2011, 22:34
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
dadius, but have you pushed them in reverse order? If that is the case you are good already ("proc" **needs** arguments in reverse order).
Post 31 Jul 2011, 23:59
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17666
Location: In your JS exploiting you and your system
revolution
The current macros proc and stdcall are designed to work with each other. The order of pushes is reversed by stdcall, and the order of reading by proc matches the order in memory that stdcall produces. Use like this:
Code:
include 'win32ax.inc'
proc Func, p1, p2

;...

stdcall Func, fname1, fname2    
However there is a problem with variable number of parameters. stdcall does not support a variable number of parameters. For that you should be using ccall and c based procs. Use like this:
Code:
include 'win32ax.inc'
proc aFunction c, FileName:BYTE, FileName2:BYTE, ParameterCount:DWORD, ...

;...

ccall aFunction, fname1, fname2, SomeCount, ...    
Post 01 Aug 2011, 06:30
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