From: Nicholas Piggin <npiggin@gmail.com>
To: Florian Weimer <fweimer@redhat.com>,
Segher Boessenkool <segher@kernel.crashing.org>
Cc: gcc@gcc.gnu.org, libc-alpha@sourceware.org,
linuxppc-dev@lists.ozlabs.org,
Paul E Murphy <murphyp@linux.ibm.com>
Subject: Re: [PATCH Linux] powerpc: add documentation for HWCAPs
Date: Fri, 15 Jul 2022 11:17:24 +1000 [thread overview]
Message-ID: <1657846871.9qtz2ahf6c.astroid@bobo.none> (raw)
In-Reply-To: <20220524183236.GJ25951@gate.crashing.org>
Excerpts from Segher Boessenkool's message of May 25, 2022 4:32 am:
> On Tue, May 24, 2022 at 11:52:00AM +0200, Florian Weimer wrote:
>> * Nicholas Piggin:
>>
>> > +2. Facilities
>> > +-------------
>> > +The Power ISA uses the term "facility" to describe a class of instructions,
>> > +registers, interrupts, etc. The presence or absence of a facility indicates
>> > +whether this class is available to be used, but the specifics depend on the
>> > +ISA version. For example, if the VSX facility is available, the VSX
>> > +instructions that can be used differ between the v3.0B and v3.1B ISA
>> > +verstions.
>>
>> The 2.07 ISA manual also has categories. ISA 3.0 made a lot of things
>> mandatory. It may make sense to clarify that feature bits for mandatory
>> aspects of the ISA are still set, to help with backwards compatibility.
>
> Linux runs on ISA 1.xx and ISA 2.01 machines still. "Category" wasn't
> invented for either yet either, but similar concepts did exist of
> course.
Not sure what to say about this. It now also has "Compliancy Subset"
although maybe that's more like a set of features rather than
incompatible features or modes such as some of the category stuff
seems to be. I'll try add something.
Thanks,
Nick
next prev parent reply other threads:[~2022-07-15 1:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-24 9:38 Nicholas Piggin
2022-05-24 9:52 ` Florian Weimer
2022-05-24 18:32 ` Segher Boessenkool
2022-07-15 1:17 ` Nicholas Piggin [this message]
2022-07-15 14:35 ` Segher Boessenkool
2022-05-24 17:38 ` Segher Boessenkool
2022-07-15 1:00 ` Nicholas Piggin
2023-06-06 14:49 ` Passing the complex args in the GPR's Umesh Kalappa
2023-06-06 14:58 ` Andrew Pinski
2023-06-06 15:05 ` Umesh Kalappa
2023-06-06 15:16 ` Andrew Pinski
2023-06-06 16:42 ` Segher Boessenkool
2023-06-06 17:07 ` Umesh Kalappa
2023-06-06 17:33 ` David Edelsohn
2023-06-07 13:17 ` Michael Matz
2023-06-06 17:18 ` Joseph Myers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1657846871.9qtz2ahf6c.astroid@bobo.none \
--to=npiggin@gmail.com \
--cc=fweimer@redhat.com \
--cc=gcc@gcc.gnu.org \
--cc=libc-alpha@sourceware.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=murphyp@linux.ibm.com \
--cc=segher@kernel.crashing.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).