[Challenge #64][1]

What does this code do?

An array of `array[x][y]` form is accessed here. Try to determine the dimensions of the array, at least partially, by finding y.

```assembly
_array$ = 8
_x$ = 12
_y$ = 16
_f	PROC
	mov	eax, DWORD PTR _x$[esp-4]
	mov	edx, DWORD PTR _y$[esp-4]
	mov	ecx, eax
	shl	ecx, 4
	sub	ecx, eax
	lea	eax, DWORD PTR [edx+ecx*8]
	mov	ecx, DWORD PTR _array$[esp-4]
	fld	QWORD PTR [ecx+eax*8]
	ret	0
_f	ENDP
```

At first I think there is a mistake in the question. Because I only see three variables here, one for array address, the one x and one y, so I assume it's actually a 2d array of double, not a 3d as in *"An array of `array[x][y]`"*.

Then I was stuck because eventually the program loads `array[8y+192x]`, and x and y can be anything.

So I figured this must be a 3d array of double, with the third dimension given. I still couldn't figure it out so I tried to write my own program and use Godbolt to give me assembly. After a few trials I got something pretty close to the original program:

[Something close][2]

However I'm still having difficulty to match my program with the original question. I think I'm pretty close but how do I proceed from here? I have a hunch that y is also 24 in the original question, but not 100% sure.


  [1]: https://challenges.re/64/
  [2]: https://godbolt.org/z/bT7bq8exa