Pointer and reference similar at assembly level

Pointer and reference maybe same at assembly level.
Try an experiment :

Code:

# include<stdio.h>
int main()
{
  int i =90;
  int *pointer;
  int &reference = i; // Line 6
  pointer = &i;  
  return 0;  // Line 8
}

compile it to assembly with Microsoft c++ like this :

Code:

c:\ cl /Fa filename.cpp

or with gcc like

Code:

c:\ gcc -S -masm=intel filename.cpp

Open the asm file like c:\ notepad filename.asm

Now you can the code of i, pointer, and reference;

Code:

 Line 6
	mov	DWORD PTR _i$[ebp], 90			; int i = 90;
; Line 8
	lea	eax, DWORD PTR _i$[ebp]                  ; int &reference = i;
	mov	DWORD PTR _reference$[ebp], eax
; Line 9
	lea	ecx, DWORD PTR _i$[ebp]               ; int *pointer
	mov	DWORD PTR _pointer$[ebp], ecx    ;  pointer = &i;

you see the code for pointer is exactly same as reference .

 

That's because C doesn't have references like C++. The & is strictly an address-of operator.

 

Dawei i am using c++ compiler if you don't believe me see this code

Code:

#include<iostream>

int main()
{
int i =90;
  int *pointer;
  int &reference = i; 
  pointer = &i;  
  return 0;  
}

Code:

	
       mov     DWORD PTR _i$[ebp], 90			;  int i = 90

	lea	eax, DWORD PTR _i$[ebp]                  ; int &reference = i; 
	mov	DWORD PTR _reference$[ebp], eax

	lea	ecx, DWORD PTR _i$[ebp]                  ; pointer = &i;
	mov	DWORD PTR _pointer$[ebp], ecx
	

the code of reference is same as code of pointer.

 

the pointer is very ueful when the use in the right way otherwise it can be damaged the our memory location.