Many things in computing are elegant and beautiful, but this is not one if them imho (the overlapping segments, the multiple pointer types, the usage of 32 bits to only access 1MB, 'medium' having less data than 'compact', ...)

> but this is not one

It really is though. Memory and thus data _and_ instruction encoding were incredibly important. Physical wires on the circuit board were at a premium then as well. It was an incredibly popular platform because it was highly capable while being stupidly cheap compared to other setups.

Engineering is all about tradeoffs. "Purity" almost never makes it on the whiteboard.

Yeah, good thing that e.g. RV64 has RIP-relative addressing mode that can address anywhere in the whole 56-bits of available space with no problems, unlike the silly 8086 that resorted to using a base register to overcome the short size of its immediate fields.