Welcome to the forum. At the risk of sounding narky, it might help if you do a quick search before asking this sort of question or re-inventing the wheel, as there are several topics on the reverse engineering and documenting of A-code and news of Mike Austin making Level 9 resources public. Here’s just a few:
- How did A-Code text compression work?
- Specification of Level 9 A-Code
- A-Code Compiler, Level 9 Archive, Specs, game sources: made public!
There are also lots of interesting links within these topics.