From: Segher Boessenkool <segher@kernel.crashing.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
linuxppc-dev@lists.ozlabs.org,
Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>,
libc-alpha@sourceware.org
Subject: Re: powerpc Linux scv support and scv system call ABI proposal
Date: Wed, 29 Jan 2020 16:36:00 -0000 [thread overview]
Message-ID: <20200129162947.GN22482@gate.crashing.org> (raw)
In-Reply-To: <87wo9a8cc8.fsf@oldenburg2.str.redhat.com>
On Wed, Jan 29, 2020 at 05:19:19PM +0100, Florian Weimer wrote:
> * Segher Boessenkool:
> >> But GCC doesn't expose them as integers to C code, so you can't do much
> >> without them.
> >
> > Sure, it doesn't expose any other registers directly, either.
>
> I can use r0 & 1 with a register variable r0 to check a bit.
That is not reliable, or supported, and it *will* break. This is
explicit for local register asm, and global register asm is
underdefined.
> I don't
> think writing a similar check against a condition register is possible
> today.
That's right. You cannot express CCmode (MODE_CC) values in C at all.
Segher
next prev parent reply other threads:[~2020-01-29 16:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 12:56 Nicholas Piggin
2020-01-28 13:58 ` Florian Weimer
2020-01-28 15:40 ` Nicholas Piggin
2020-01-28 15:55 ` Segher Boessenkool
2020-01-28 16:19 ` Florian Weimer
2020-01-28 17:02 ` Dan Horák
2020-01-28 20:38 ` Segher Boessenkool
2020-01-29 16:30 ` Florian Weimer
2020-01-29 16:36 ` Segher Boessenkool [this message]
2020-01-29 17:40 ` Florian Weimer
2020-01-29 18:59 ` Segher Boessenkool
2020-01-30 11:03 ` Florian Weimer
2020-01-30 12:04 ` Segher Boessenkool
2020-01-30 12:34 ` Florian Weimer
2020-01-30 14:34 ` Segher Boessenkool
2020-01-30 17:59 ` Adhemerval Zanella
2020-01-30 22:05 ` Segher Boessenkool
2020-01-31 11:33 ` Adhemerval Zanella
2020-01-31 12:12 ` Segher Boessenkool
2020-01-28 16:05 ` Florian Weimer
2020-01-29 11:18 ` Nicholas Piggin
2020-01-28 16:25 ` Adhemerval Zanella
[not found] ` <cd9e4b28-d577-8850-7c2b-a488fcb4740d@linaro.org>
[not found] ` <1580273424.ea818exa2c.astroid@bobo.none>
2020-01-29 16:19 ` Tulio Magno Quites Machado Filho
2020-02-19 11:04 ` Nicholas Piggin
2020-01-28 23:18 ` 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=20200129162947.GN22482@gate.crashing.org \
--to=segher@kernel.crashing.org \
--cc=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=npiggin@gmail.com \
--cc=tuliom@linux.ibm.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).