The companies that design processors all provide specifications of their products. These specifications are usually in the form of books or PDF documents.
It is then up to diligent engineers and academics around the world to read those documents and transcribe the relevant parts into computer languages such as C, C++, Verilog, O’Caml, Coq, Isabelle, … to implement tools that generate, dissect or analyse programs for those processors. This is a very tedious, error-prone process.
ARM has released version 8.2 of the ARM v8-A processor specification in machine readable form.
The semantics is written in ARM’s ASL Specification Language so it is all executable and has been tested very thoroughly.
If this is for real, what you think you can you do with this?