From: Palmer Dabbelt <palmer@dabbelt.com>
To: Kito Cheng <kito.cheng@gmail.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] RISC-V: Note that __builtin_riscv_pause() implies Xgnuzihintpausestate
Date: Mon, 28 Nov 2022 10:45:51 -0800 (PST) [thread overview]
Message-ID: <mhng-7d4d748f-c527-49c1-b6d5-ea34e9a8baba@palmer-ri-x1c9a> (raw)
In-Reply-To: <mhng-68270cff-b8b7-41c8-a9a8-ebabe85b8808@palmer-ri-x1c9>
On Fri, 18 Nov 2022 09:01:08 PST (-0800), Palmer Dabbelt wrote:
> On Thu, 17 Nov 2022 22:59:08 PST (-0800), Kito Cheng wrote:
>> Wait, what's Xgnuzihintpausestate???
>
> I just made it up, it's defined right next to the name like those
> profile extensions are. I figured that's the most RISC-V way to define
> something like this, but we could just drop it and run with the
> definition -- IIRC we just stuck a comment in for Linux and QEMU, I
> doubt anyone is actually going to implement the "doesn't touch PC"
> version of pause.
Just checking up on this one. I don't care a ton about the name, just
that we document where we're intentionally violating the specs.
>
>> On Fri, Nov 18, 2022 at 12:30 PM Palmer Dabbelt <palmer@rivosinc.com> wrote:
>>>
>>> gcc/ChangeLog:
>>>
>>> * doc/extend.texi (__builtin_riscv_pause): Imply
>>> Xgnuzihintpausestate.
>>> ---
>>> gcc/doc/extend.texi | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
>>> index b1dd39e64b8..26f14e61bc8 100644
>>> --- a/gcc/doc/extend.texi
>>> +++ b/gcc/doc/extend.texi
>>> @@ -21103,7 +21103,9 @@ Returns the value that is currently set in the @samp{tp} register.
>>> @end deftypefn
>>>
>>> @deftypefn {Built-in Function} void __builtin_riscv_pause (void)
>>> -Generates the @code{pause} (hint) machine instruction.
>>> +Generates the @code{pause} (hint) machine instruction. This implies the
>>> +Xgnuzihintpausestate extension, which redefines the @code{pause} instruction to
>>> +change architectural state.
>>> @end deftypefn
>>>
>>> @node RX Built-in Functions
>>> --
>>> 2.38.1
>>>
next prev parent reply other threads:[~2022-11-28 18:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-18 4:27 Palmer Dabbelt
2022-11-18 6:59 ` Kito Cheng
2022-11-18 17:01 ` Palmer Dabbelt
2022-11-28 18:45 ` Palmer Dabbelt [this message]
2022-12-16 16:48 ` Palmer Dabbelt
2022-12-17 9:40 ` Andrew Waterman
2022-12-17 10:10 ` Andreas Schwab
2022-12-17 10:16 ` Andrew Waterman
2022-12-17 10:21 ` Andreas Schwab
2022-12-17 10:39 ` Andrew Waterman
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=mhng-7d4d748f-c527-49c1-b6d5-ea34e9a8baba@palmer-ri-x1c9a \
--to=palmer@dabbelt.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=kito.cheng@gmail.com \
/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).