In this article, we will first write a small piece of C code that uses arithmetic operations and then translate the code into x86 assembly language and analyze the assembly code. After that, we will take another piece of assembly code, analyze it and try to construct the corresponding C code that uses arithmetic operations.

Let’s first write a small piece of code in C that performs a simple addition of two integer variables.

#include <stdio.h>
int main() {
        int a = 1, b = 2, c;
        c = a + b;
        return 0;
}

Now, let’s compile the above code and generate the corresponding object code.

$ gcc -c arithmetic_operations.c
$ objdump -M intel -d arithmetic_operations.o

Please note that the “-M intel” option will generate the assembly code in the Intel syntax.

The corresponding assembly code will look like the following:

0000000000000000 <main>:
   push   rbp
   mov    rbp,rsp
   mov    DWORD PTR [rbp-0xc],0x1
   mov    DWORD PTR [rbp-0x8],0x2
   mov    edx,DWORD PTR [rbp-0xc]
   mov    eax,DWORD PTR [rbp-0x8]
   add    eax,edx
   mov    DWORD PTR [rbp-0x4],eax
   mov    eax,0x0
   pop    rbp
   ret    

The first two instructions are part of the function prologue and they are executed every time a function is called. The RBP …