Question

I am messing around with assembly for the first time, and can’t seem to change the index values of an array. Here’s the method I am working on

int ascending_sort( char arrayOfLetters[], int arraySize )
 {
   char temp;

__asm
    {

   //???
      }
}

And these are what I tried

mov temp, 'X'
mov al, temp
mov arrayOfLetters[0], al

And this gave me an error C2415: improper operand type

so I tried

mov temp, 'X'
mov al, temp
mov BYTE PTR arrayOfLetters[0], al

This complied, but it didn’t change the array…

Answer 1

The arrayOfLetters value is equivalent to a pointer. So, your assembly code might need to be:

mov temp, 'X' 
mov al, temp 
mov edx, arrayOfLetters
mov [edx], al 

In the above code, edx is loaded with the address of arrayOfLetters. Then the last instruction stores the al byte into the address pointed to by edx.