64bit inline ASM workaround

Deutschland demiş ki:This was something I was interested in, when I was attempting to create a virus that would run in both 64 and 32bit. But I relied on inline assembly, unfortunately Microsoft's compiler doesn't support it.

So I figured, I'll Assemble it and then link it to the project. Call the function from the static lib. And wow it worked!

Take this function.

Kod:


__declspec(naked) int __cdecl add(int x, int y)
{
  __asm
  {
    push ebp
    mov ebp,esp
    mov eax,[ebp+0xC]
    mov edx,[ebp+0x8]
    add eax,edx
    pop ebp
    ret
  }
}


Compile that in 32bit, works fine! Compile in 64bit, you'll get an annoying Microsoft error.
So here's what we can do, create an assembly file. Just toss our code in there.

Kod:


.global _add
_add:
   push ebp
   mov ebp, esp
   mov eax, [ebp+0xC]
   mov edx, [ebp+0x8]
   add eax,edx
   pop ebp
   ret


Assemble it to an object file or static lib.
Then link it to your project

Kod:


#pragma comment(lib,"add.lib");


Include the add.h file which contains.

Kod:


int add(int x, int y);


And try it out.

Kod:


int main()
{
  printf("%i",add(25,10));
  return 0;
}


Compile in 64, and see for your self!
This is also useful for Gunz hackers who want to distribute their functions for use, but not want to give out the source.