This whitepaper details the architectural enhancements and modifications that Intel is currently investigating for a 64-bit mode-only architecture referred to as x86S (for simplification). Intel is publishing this paper to solicit feedback from the ecosystem while exploring the benefits of extending the ISA transition to a 64-bit mode-only solution.
This seems like a very good idea – and it does seem like the time is ripe to remove some of the unused cruft from x86. Intel is proposing removing removing the 16 bit and 32 bit modes, and instead start in 64 bit mode right away. The company’s proposal does retain the ability to run 32 bit code on a 64 bit operating system, though.
As a sidenote, the introduction to this proposal is hilarious:
Since its introduction over 20 years ago, the Intel® 64 architecture became the dominant operating mode. As an example of this evolution, Microsoft stopped shipping the 32-bit version of their Windows 11 operating system. Intel firmware no longer supports non UEFI64 operating systems natively. 64-bit operating systems are the de facto standard today. They retain the ability to run 32-bit applications but have stopped supporting 16-bit applications natively.
It’s 2023, and Intel is still not, in any way, capable of acknowledging AMD for coming up with AMD64. Sad.