From: Matthew Wilcox <matthew@wil.cx>
To: linux-kernel@vger.kernel.org, fare@tunes.org
Cc: Grant Grundler <grundler@parisc-linux.org>
Subject: Bug in cpu_to_le32
Date: Mon, 1 Nov 2004 02:23:11 +0000 [thread overview]
Message-ID: <20041101022311.GG8958@parcelfarce.linux.theplanet.co.uk> (raw)
Grant Grundler spotted we weren't using the optimised byteswap routines
on PA-RISC. Here's why:
include/linux/byteorder/generic.h:90:#define le32_to_cpu __le32_to_cpu
include/linux/byteorder/big_endian.h:33:#define __le32_to_cpu(x) ___swab32((__force __u32)(__le32)(x))
and byteorder/swab.h:
#define ___swab32(x) \
({ \
__u32 __x = (x); \
((__u32)( \
(((__u32)(__x) & (__u32)0x000000ffUL) << 24) | \
(((__u32)(__x) & (__u32)0x0000ff00UL) << 8) | \
(((__u32)(__x) & (__u32)0x00ff0000UL) >> 8) | \
(((__u32)(__x) & (__u32)0xff000000UL) >> 24) )); \
})
So le32_to_cpu() doesn't use optimised assembler on any platform. And for
all you using ext3 on i386 ...
include/linux/byteorder/generic.h:95:#define cpu_to_be32 __cpu_to_be32
include/linux/byteorder/little_endian.h:38:#define __cpu_to_be32(x) ((__force __be32)___swab32((x)))
So it's not being used there either. What is ___swabN() for anyway? It seems
to be a duplicate of ___constant_swabN().
--
"Next the statesmen will invent cheap lies, putting the blame upon
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince
himself that the war is just, and will thank God for the better sleep
he enjoys after this process of grotesque self-deception." -- Mark Twain
reply other threads:[~2004-11-01 2:23 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=20041101022311.GG8958@parcelfarce.linux.theplanet.co.uk \
--to=matthew@wil.cx \
--cc=fare@tunes.org \
--cc=grundler@parisc-linux.org \
--cc=linux-kernel@vger.kernel.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
Powered by JetHome