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Forum Index > Source Help > 'frame off' + 'push\pop' + 'using'
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0CodErr
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[1845] 'frame off' + 'push\pop' + 'using' - posted: 2016-05-03 10:08:05
This function Code:
#set frame off;
function test(dword x) {
  eax = x;
  using eax{eax = x}
  push eax
  mov eax, x
  pop eax
}
translates to Code:
        mov    eax, [esp + 4]
        push   eax
        mov    eax, [esp + 8]
        pop    eax
        push   eax
        mov    eax, [esp + 8]
        pop    eax
        ret    4
As we can see the offset of 'x' after 'push' is calculated correctly. Can you explain how it works and in which case it may not work?
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[1850] - posted: 2016-05-03 17:28:08
The method I have wrote to track the stack works quite well, but it does have flaws, I can't say exactly what they are since I have not tested 100% everything, but if you find any bugs, just let me know smile

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0CodErr
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Posts: 199
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[1852] - posted: 2016-05-03 18:04:04
Some code is added in function: Code:
#set frame off;
function test(dword x) {
  eax = x;
  using eax{eax = x}  
  push eax
  mov eax, x
  pop eax
  
  using ax{eax = x}
  push ax
  mov eax, x
  pop ax
  
  esp--;
  mov eax, x
  esp++;
}
Result: Code:
        mov    eax, [esp + 4]
        push   eax
        mov    eax, [esp + 8]
        pop    eax
        push   eax
        mov    eax, [esp + 8]
        pop    eax
        push   eax
        mov    eax, [esp + 6]
        pop    eax
        push   eax
        mov    eax, [esp + 6]
        pop    eax
        dec    esp
        mov    eax, [esp + 4]
        inc    esp
        ret    4
If esp changed directly then result incorrect. After [olor=#0011ff]using ax[/color] offset correct but push eax used instead of push ax.
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