Question

I have a method (C++) that returns a character and takes an array of characters as its parameters.

I’m messing with assembly for the first time and just trying to return the first character of the array in the dl register. Here’s what I have so far:

char returnFirstChar(char arrayOfLetters[])
{
 char max;

 __asm
 {
  push eax
      push ebx
       push ecx
     push edx
  mov dl, 0

  mov eax, arrayOfLetters[0]
  xor edx, edx
  mov dl, al

  mov max, dl       
  pop edx
  pop ecx
  pop ebx
  pop eax

 }

 return max;
}

For some reason this method returns a ♀

Any idea whats going on? Thanks

Answer 1

The line of assembly:

mov eax, arrayOfLetters[0]

is moving a pointer to the array of characters into eax (note, that’s not what arrayOfLetters[0] would do in C, but assembly isn’t C).

You’ll need to add the following right after it to make your little bit of assembly work:

mov al, [eax]