AW1/2 RNG storage

Advance wars 1/2 RNG storage.

In the first 2 advance wars games, when you save the game mid-battle, the RNG is also saved, presumable in an attempt to prevent save scumming. While there are methods of advancing the RNG, such as loading the save, or viewing the CO page in AW2, you aren't able to do any real RNG manipulation, just give yourself multiple chances of getting the outcome you want. However, if you save between missions, it does not load a saved RNG seed when you reload, so we can start a mission with a specific RNG seed.

There are several ways we can do this.

1) During the game's intro screen, the RNG advances once per frame. By starting the game on a specific frame, or ideally cluster of frames, then loading the save from earlier, we will get the same results (assuming relatively consistent execution in the mission)
This is the fastest option (other than no manip) as it involves no timeloss other than waiting for the correct frame. However, hitting the frame-perfect input can be inconsistent, and it may not be possible to verify the RNG seed during the mission.

2) Same as (1), but open up design map before resuming the Campaign. This costs around 8 seconds, but allows you to verify your seed before the mission, allowing you to vary cursor movement during the mission to get the desired result as long as the seed you hit initially was one you planned for.

Note: Adjacent RNG frames during the intro do not produce adjacent RNG frames after doing this, so each frame in the cluster will potentially require very different cursor movement in battle.

There is however, a much more consistent option

3) If you resume then exit a war room/versus game in progress, it will load in the saved RNG seed from that game. You are then able to resume the Campaign with this RNG seed, effectively allowing you to store 2 RNG seed for use later. This is also just as fast as option (2), so is obviously the superior option if looking for consistency.

As for acquiring the seed we wish to store, this should probably be done using something similar to method 2, verifying where we are in the RNG, using the CO page to advance to the desired point. Note that what is important is the RNG you'll have AFTER reloading the save, so you'll want to advance to 2 before that.

As for when this is worth doing, Rain of Fire in AW2, as using this trick effectively gives you second try every time, when on average it should take ~5-6. Unfortunately, RNG advances every frame when selecting attacks, so things like manipulating the turn save on Silo Scramble are off the table. Consistent Fighter/A-Air-less Final front may also be worth it, but this would involve holding manip through an attack on the missile.

The RNG seems to advance much less in AW1 than AW2, where holding manip for entire fights such as The Final Battle seems like it may be feasible, so hopefully that game can be made bearable enough to do runs.

WIP RoF manip setup:
start game ASAP
Load map editor
Start new VS game
(23661574) Advance twice, save
(39ef5d85) save
(0bac6ffe) save

During battle, must advance once to get favourable inf movement on 2336