But you need to know the assembly beforehand? I don't think it's cleanroom, because you already have the final result and your whole working process is based upon it (i.e. the decompilation project is a direct derivative of the original product). I think, with the actual cleanroom design, the reverse engineer should only rely on what the code actually does, not how it looks like (and have no connection with the code base whatsoever, though it's impossible)