Sort an array via x86 Assembly (embedded in C++)?? Possible?

问题

I am playing around with x86 assembly for the first time and I can't figure out how to sort an array (via insertion sort).. I understand the algorithm, but assembly is confusing me as I primarily use Java & C++. Heres all I have so far

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

 __asm{

     push eax
     push ebx
      push ecx
     push edx
    push esi
    push edi

//// ???

    pop edi
    pop esi
       pop edx
    pop ecx
     pop ebx
    pop eax
 }
}

Basically nothing :( Any ideas?? Thanks in advance.

Ok, this is just going to make me sound like a total idiot, but I can't even change any of the array's values in _asm

Just to test it out, I put:

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

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...

回答1:

This code is in now way tested. I wrote it in notepad, which doesn't have a very good debugger, off the top of my head. It should be a good starting place however:

mov edx, 1                                  // outer loop counter

outer_loop:                                 // start of outer loop
  cmp edx, length                           // compare edx to the length of the array
  jge end_outer                             // exit the loop if edx >= length of array

  movzx eax, BYTE PTR arrayOfLetters[edx]   // get the next byte in the array
  mov ecx, edx                              // inner loop counter
  sub ecx, 1

  inner_loop:                               // start of inner loop
    cmp eax, BYTE PTR arrayOfLetters[ecx]   // compare the current byte to the next one
    jg end_inner                            // if it's greater, no need to sort

    add ecx, 1                              // If it's not greater, swap this byte
    movzx ebx, BYTE PTR arrayOfLetters[ecx] // with the next one in the array
    sub ecx, 1
    mov BYTE PTR arrayOfLetters[ecx], bl
    sub ecx, 1                              // loop backwards in the array
    jnz inner_loop                          // while the counter is not zero

  end_inner:                                // end of the inner loop

  add ecx, 1                                // store the current value
  mov BYTE PTR arrayOfLetters[ecx], al      // in the sorted position in the array
  add edx, 1                                // advance to the next byte in the array
  jmp outer_loop                            // loop

end_outer:                                  // end of outer loop

This would have been MUCH easier if you were sorting DWORD values (int) instead of BYTE values (characters).

来源：https://stackoverflow.com/questions/2643341/sort-an-array-via-x86-assembly-embedded-in-c-possible

标签

c++

assembly

x86

insertion-sort