From: linas@austin•ibm.com (Linas Vepstas)
To: Paul Mackerras <paulus@samba•org>
Cc: ppc-dev <linuxppc-dev@ozlabs•org>,
Stephen Rothwell <sfr@canb•auug.org.au>
Subject: Re: [PATCH]: powerpc documentation: Clarify why twi appears in the i/o macros.
Date: Fri, 8 Dec 2006 19:21:26 -0600 [thread overview]
Message-ID: <20061209012126.GC13128@austin.ibm.com> (raw)
In-Reply-To: <17786.267.627624.105175@cargo.ozlabs.ibm.com>
On Sat, Dec 09, 2006 at 11:19:23AM +1100, Paul Mackerras wrote:
> Segher Boessenkool writes:
>
> > If you argue it is *not* a branch, where in the architecture
> > documentation can we find any language that gives us the
> > guarantee we depend on here?
>
> isync is context synchronizing. In the definition of context
> synchronization, it says "2. The operation is not initiated, or in
> the case of isync, does not complete, until all instructions already
> in execution have completed to a point at which they have reported all
> exceptions they will cause". The twi conditionally causes an
> exception depending on the data from the previous load, therefore it
> cannot complete to a point at which is has reported all exceptions it
> will cause until it sees the data from the load. Therefore the isync
> cannot complete (and allow following instructions to start) until the
> data from the load has returned.
I'd be happy if this text, verbatim or suitably massaged, were
included in the header file.
--linas
next prev parent reply other threads:[~2006-12-09 1:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-06 18:29 [PATCH]: powerpc documentation: Clarify why twi appears in the i/o macros Linas Vepstas
2006-12-06 18:39 ` Sergei Shtylyov
2006-12-06 19:45 ` Linas Vepstas
[not found] ` <45772700.2080708@ru.mvista.com>
2006-12-06 22:22 ` Linas Vepstas
2006-12-08 2:58 ` Paul Mackerras
2006-12-08 21:54 ` Segher Boessenkool
2006-12-09 0:11 ` Linas Vepstas
2006-12-09 0:19 ` Paul Mackerras
2006-12-09 1:21 ` Linas Vepstas [this message]
2006-12-09 9:32 ` Segher Boessenkool
2006-12-11 2:37 ` Paul Mackerras
2006-12-11 16:37 ` Segher Boessenkool
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=20061209012126.GC13128@austin.ibm.com \
--to=linas@austin$(echo .)ibm.com \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=paulus@samba$(echo .)org \
--cc=sfr@canb$(echo .)auug.org.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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