Go4Expert - Pointer and reference similar at assembly level

Go4Expert (http://www.go4expert.com/)

- C (http://www.go4expert.com/forumdisplay.php?f=60)

- - Pointer and reference similar at assembly level (http://www.go4expert.com/showthread.php?t=5882)

Pointer and reference similar at assembly level

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

Code: C

# 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 .

Re: Pointer and reference similar at assembly level

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

Re: Pointer and reference similar at assembly level

He is using a cpp file and so the compiler is C++.

Re: Pointer and reference similar at assembly level

Quote:

Originally Posted by DaWei

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.

Re: Pointer and reference similar at assembly level

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