Simple add function
Simple add function
Hello guys, I am trying to learn asm and I am in need of some help. How come this does not work?
As you can see I am very new to asm.
Code:
#include <stdio.h>
#include <iostream>
int add(int num1, int num2);
using namespace std;
int main(void)
{
int result = add(3, 2);
cout << result;
system("pause");
}
int add(int num1, int num2)
{
int result = 0;
__asm
{
mov result, offset num1
push result
mov result, offset num2
push result
}
return result;
}
I'm not great at asm and even worse on mixed programming but I can tell you this: offset means you're going to be getting the memory addresses for num1 and num2. You should be pushing the values themselves, I think. Try using this:
Also, what error are you getting?
Edit: Right now I can't test the code but later I'll test at home and try to help you. You should also look for assembly command sheets, they're very helpful
mov result, num1
add result, num2
or
push num1
push num2
fadd
pop result
add result, num2
or
push num1
push num2
fadd
pop result
Edit: Right now I can't test the code but later I'll test at home and try to help you. You should also look for assembly command sheets, they're very helpful
Originally Posted by samlarenskoog
Your question
Code:
#include "stdafx.h"
#include <stdio.h>
#include <iostream>
using namespace std;
int add(int num1, int num2)
{
int result;
__asm
{
xor eax, eax;
mov eax, num1;
add eax, num2;
mov result, eax;
}
return result;
}
int main()
{
int result, a, b;
cout << "Variable 1: ";
cin >> a;
cout << "Variable 2: ";
cin >> b;
result = add(a, b);
cout << result << endl;
system("pause");
}
I forgot to explain what XOR EAX, EAX is for, it will set EAX to 0, or in other words, clear the address
Originally Posted by FatAssHacker123
I forgot to explain what XOR EAX, EAX is for, it will set EAX to 0, or in other words, clear the address
Also, why are you not using naked functions?
Originally Posted by samlarenskoog
Hello guys, I am trying to learn asm and I am in need of some help. How come this does not work?
As you can see I am very new to asm.
Code:
#include <stdio.h>
#include <iostream>
int add(int num1, int num2);
using namespace std;
int main(void)
{
int result = add(3, 2);
cout << result;
system("pause");
}
int add(int num1, int num2)
{
int result = 0;
__asm
{
mov result, offset num1
push result
mov result, offset num2
push result
}
return result;
}
2. In GCC you use asm(), not asm{}.
3. If you are using GCC, you will also need to do a manual clobbering. For VC++, you won't.
