Have you actually done this? Do you really think we haven't?
The Appel book in particular is very good, but it only covers assembly generation at a high level. None of the examples target a real-world architecture.
I don't know what you have done. The red dragon book goes over targeting an intermediate form that's basically assembly language, it also covers register allocation in depth. As far as I can tell, most of the texts after that is in research papers and real world examples (https://c9x.me/compile/)
