Yes, I hit it a lot during my Z80 days, too. I also had to do manual memory management using a memory-mapped page register. We all have our constraints we must

Yes, I hit it a lot during my Z80 days, too. I also had to do manual memory management using a memory-mapped page register. We all have our constraints we must operate under, and a bag of tools to help deal with those constraints. But "unsigned by default" won't save you here; all it does is give you a little more breathing room for your special case code (and hey, maybe that doubled positive integer space is all you needed, in which case congrats). But all of the other problems are still there. That's why I'm saying that "unsigned by default" is backwards. It should be "signed by default", and unsigned for special situations that warrant it.