Seriously though, I’ve been wondering for a while whether I could build a GCC for x86-64 that would have 32-bit (low 4G) pointers (and no REX prefixes) by default and full 64-bit ones with __far or something. (In this episode of Everything Old Is New Again: the Very Large Memory API[1] from Windows NT for Alpha.)
[1] https://devblogs.microsoft.com/oldnewthing/20070801-00/?p=25...