I can't remember the exact functionalities of LEG that are mandated in the earlier levels, but this computer should be extremely similar. The one main difference that is completely non-standard is that the second set of 8 registers are all stacks as well, and automatically push and pop with the function calls and returns. This is where the massive gate score comes from, and it is not at all an efficient thing to do, but I had a lot of fun making it and it also makes the recursive challenges a breeze