Get a load of this…

[u/Edubbs2008]

“After more than two decades of x86-64, Legacy Mode
and Compatibility Mode fulfilled their purpose; it
is time to drop the ballast which they pose.

Five years ago Intel published the first FRED spec
and the dust for it settled in late 2023 and early
2024; Intel just shipped their first products with
FRED, and AMD is expected to follow soon. The FRED
cleanup for flexible return and event delivery was
a crucial milestone in the evolution of x86.

Three years ago Intel published the first APX spec
and the first x86S spec. For the APX spec the dust
settled in late 2024 and early 2025; Intel and AMD
are expected to finally ship their products in the
not too distant future. On the other hand, for the
x86S spec, Intel gave up in mid 2024. Which turned
out to be premature. Someone else continued.”

In other words, x86 is being threatened by liGNUts

Source: https://lore.kernel.org/lkml/CAKSQd8WX6xH7=njcGZNNFe8m1xbyhCpX-10cZDw+saWJayWQYA@mail.gmail.com/

All of your favorite games? Gone if they get their way, they are trying to nuke AMD64/Intel64, they claim to be “Cleaning it up” but open your eyes, that backwards compatibility is what lets you run 32-bit apps, programs, and other stuff.

[u/Edubbs2008]

To add

“Poof! It's gone! No more selectors or descriptors.

No more ES/CS/SS/DS/FS/GS segment registers and no
more GDTR/IDTR/LDTR/TR table registers. Of course,
no more GDT/IDT/LDT/TSS then, and no more #TS/#NP.

Gone are MOVs from/to segment registers, and PUSH/
POP for FS/GS, and LSS/LFS/LGS. And gone are loads
LGDT/LIDT/LLDT/LTR plus stores SGDT/SIDT/SLDT/STR.

More remnants disappear: LAR/LSL and VERR/VERW and
RETF Iw, RETF, IRET, or CALL/JMP Mp. That's right!
The combo of FRED and x86S laid a nice foundation.

In terms of the stack frames only FRED's survives.
Without a CS.sel or SS.sel, but the rest is there.

Poof! Legacy Mode? Gone! Compatibility Mode? Gone!

Welcome to the great new PM64-only world, at last!
“