Your CPU designer friends are right, and your "emulator" is pretty much how real mode and v8086 protected mode addressing were actually architected. The descri

Your CPU designer friends are right, and your "emulator" is pretty much how real mode and v8086 protected mode addressing were actually architected. The descriptor parts of segment registers effectively had fixed contents derived from what was loaded into the selector parts, rather than from descriptor tables. Yes, this indeed allowed the 80386 to run real mode programs. (-: