How should I to understand this string?

04B1FA: 3031 3233 move.w INVALID 31, D0
And isn't it a time to puzzle out finally, what concrete in-game processes are hiding behind all these computations and endless numbers interchange between registers and/or memory, before I get confused in my comments by bell, book and candle? Just look to 04B1B4 string, and you'll see how impossibly long and complicated the expressions became!