[PATCH v3 10/10] x86-64: Intel64 adjustments for insns dealing with far pointers

[Jan Beulich]

On 16.01.2020 21:24,  H.J. Lu  wrote:
> We should improve gas documentation.  The current far branches
> work fine.  Why bother to add new far branches without giving
> developer a clue how to use them?

That's the subject of CPU documentation, not that of any assembler.
The current far branches "work fine" as far as they're being made
accessible (encodable) by gas. The 64-bit forms Intel CPUs support
didn't work fine at all (because one had to use hand crafted REX.W
prefixes), as per Andrew's bug report. There's no difference here
to the prior work you did to support the Intel64 / AMD64
differences for certain other insns - you've simply made gas
capable of properly encoding them in a vendor dependent manner.
You didn't accompany this with any documentation explaining "how
to use" these. If, retroactively, you think this should have been
accompanied by such documentation, may I ask that you add such,
which will then allow me to see what I could (should as per your
opinion) add for the corrected variants here? Recall - I _still_
don't know what exactly you're after.

This would then further allow me to know whether the remaining
Intl64 / AMD64 differences that gas doesn't properly support yet
will also need to be accompanied by doc updates when I get around
to adjusting them.

Jan