Advanced Micro Devices Inc (AMD)

[HailMary]

From the operating-system viewpoint, however, address translation, interrupt and exception handling, and system data structures use the 64-bit long-mode mechanisms.

I understand everything you said, and I agree it is simpler from both the app and o/s standpoint, but from a chip design standpoint, all the segmentation logic is still active and will not be able to be designed out of future chips. That is how this whole discussion started. 64-bit compatibility mode supports all legacy forms of segmentation, even if modern apps and os-es tend to use a flat memory model. Segment base values of 0 disable segment translation resulting in this flat model, but the hardware still supports non-0 values in compatibility mode, even if it goes unused by programmers.

Also, the memory protection you reference is now provided by a page protection mechanism, not segmentation. In long mode, there are no longer any segmentation protection checks.