Interesting enough, the current 64-bit ObjC runtime does something similar, with so-called "tagged pointers". https://www.mikeash.com/pyblog/friday-qa-2013-09-

Interesting enough, the current 64-bit ObjC runtime does something similar, with so-called "tagged pointers". https://www.mikeash.com/pyblog/friday-qa-2013-09-27-arm64-and-you.html https://www.mikeash.com/pyblog/friday-qa-2013-09-27-arm64-an...