Replies to post #27619 on Advanced Micro Devices Inc (AMD)

[sgolds]

HailMary -

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.

Not true. Real Mode and Virtual 8086 mode are not supported.

Also, you are missing a fundamental point: The segmentation which is supported in Compatibility Mode is an emulation layer which translates to the same 64-bit mechanisms used in 64-bit mode. The fundamental design of Long Mode is not at all dependent on any Protected Mode segmentation.

So I am happy to report that your assertion that all the segmentation logic is still active and will not be able to be designed out of future chips is an incorrect conclusion. Real and Virtual 8086 logic goes away as soon as Legacy Mode is dumped. Eventually, Compatibility Mode can go away, but that will take many more years.