reference-is-a-sugar-for-a-pointer.txt

C++ source:

void call_by_reference(int& x)
{
  x = 20;
}

void call_by_pointer(int* x)
{
  *x = 20;
}

void call_by_value(int x)
{
  x = 20;
}

int _tmain(int argc, _TCHAR* argv[])
{
  int y = 0;

  call_by_reference(y);
  call_by_pointer(&y);
  call_by_value(y);

  return 0;
}

Disassembly:

The most important lines are 50-51 (by-reference) and 55-56 (by-pointer)
as we see, the same - load effective address and push to stack

int _tmain(int argc, _TCHAR* argv[])
{
00F81480  push        ebp
00F81481  mov         ebp,esp
00F81483  sub         esp,0CCh
00F81489  push        ebx
00F8148A  push        esi
00F8148B  push        edi
00F8148C  lea         edi,[ebp-0CCh]
00F81492  mov         ecx,33h
00F81497  mov         eax,0CCCCCCCCh
00F8149C  rep stos    dword ptr es:[edi]
  int y = 0;
00F8149E  mov         dword ptr [y],0

  call_by_reference(y);
00F814A5  lea         eax,[y]
00F814A8  push        eax
00F814A9  call        call_by_reference (0F81005h)
00F814AE  add         esp,4
  call_by_pointer(&y);
00F814B1  lea         eax,[y]
00F814B4  push        eax
00F814B5  call        call_by_pointer (0F8100Fh)
00F814BA  add         esp,4
  call_by_value(y);
00F814BD  mov         eax,dword ptr [y]
00F814C0  push        eax
00F814C1  call        by_value (0F8100Ah)
00F814C6  add         esp,4

  return 0;
00F814C9  xor         eax,eax
}