I can tell you from reading the code in the 90s, no LLM will save you. It’s well written, but it’s not structured like modern programs. IIRC he invented his own trampoline system using goto that will leave you scratching your head for days, just trying to figure out how it works. An LLM might be able to guess, but it def isn’t going to one-shot it and that means you will need to be able to understand it as well.