From: James Hogan <james.hogan@mips.com>
To: "Maciej W. Rozycki " <macro@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>, <linux-mips@linux-mips.org>
Subject: Re: [PATCH] MIPS: Use SLL by 0 for 32-bit truncation in `__read_64bit_c0_split'
Date: Wed, 8 Nov 2017 22:06:44 +0000 [thread overview]
Message-ID: <20171108220643.GP15260@jhogan-linux> (raw)
In-Reply-To: <alpine.DEB.2.00.1709291502060.12020@tp.orcam.me.uk>
[-- Attachment #1: Type: text/plain, Size: 863 bytes --]
On Fri, Sep 29, 2017 at 04:26:31PM +0100, Maciej W. Rozycki wrote:
> Optimize `__read_64bit_c0_split' and reduce the instruction count by 1,
> observing that a DSLL/DSRA pair by 32, is equivalent to SLL by 0, which
> architecturally truncates the value requested to 32 bits on 64-bit MIPS
> hardware regardless of whether the input operand is or is not a properly
> sign-extended 32-bit value.
>
> Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
> ---
> Tested by compilation only to verify syntax correctnes as I do not know
> if this execution path is actually used by any configuration (suggestions
> welcome). I believe it to be technically correct though, being
> sufficiently straightforward to verify by proofreading, and an obvious
> improvement.
>
> Therefore, please apply.
Thanks, Applied for 4.15.
Cheers
James
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
WARNING: multiple messages have this Message-ID (diff)
From: James Hogan <james.hogan@mips.com>
To: "Maciej W. Rozycki " <macro@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: Use SLL by 0 for 32-bit truncation in `__read_64bit_c0_split'
Date: Wed, 8 Nov 2017 22:06:44 +0000 [thread overview]
Message-ID: <20171108220643.GP15260@jhogan-linux> (raw)
Message-ID: <20171108220644.A2EgqAu7GP6L-0pUkBr86UjqXrq4XEt7J0I9agnunlI@z> (raw)
In-Reply-To: <alpine.DEB.2.00.1709291502060.12020@tp.orcam.me.uk>
[-- Attachment #1: Type: text/plain, Size: 863 bytes --]
On Fri, Sep 29, 2017 at 04:26:31PM +0100, Maciej W. Rozycki wrote:
> Optimize `__read_64bit_c0_split' and reduce the instruction count by 1,
> observing that a DSLL/DSRA pair by 32, is equivalent to SLL by 0, which
> architecturally truncates the value requested to 32 bits on 64-bit MIPS
> hardware regardless of whether the input operand is or is not a properly
> sign-extended 32-bit value.
>
> Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
> ---
> Tested by compilation only to verify syntax correctnes as I do not know
> if this execution path is actually used by any configuration (suggestions
> welcome). I believe it to be technically correct though, being
> sufficiently straightforward to verify by proofreading, and an obvious
> improvement.
>
> Therefore, please apply.
Thanks, Applied for 4.15.
Cheers
James
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2017-11-08 22:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-29 15:26 [PATCH] MIPS: Use SLL by 0 for 32-bit truncation in `__read_64bit_c0_split' Maciej W. Rozycki
2017-09-29 15:26 ` Maciej W. Rozycki
2017-09-29 19:59 ` James Hogan
2017-09-29 19:59 ` James Hogan
2017-09-29 22:39 ` Maciej W. Rozycki
2017-09-29 22:39 ` Maciej W. Rozycki
2017-11-08 22:06 ` James Hogan [this message]
2017-11-08 22:06 ` James Hogan
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=20171108220643.GP15260@jhogan-linux \
--to=james.hogan@mips.com \
--cc=linux-mips@linux-mips.org \
--cc=macro@mips.com \
--cc=ralf@linux-mips.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