From: Al Viro <viro@ZenIV.linux.org.uk>
To: chas3@users.sourceforge.net
Cc: Roel Kluin <roel.kluin@gmail.com>,
netdev@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] ATM: misplaced parentheses?
Date: Mon, 16 Feb 2009 22:30:01 +0000 [thread overview]
Message-ID: <20090216223001.GW28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <200902162202.n1GM2aI0009056@cmf.nrl.navy.mil>
On Mon, Feb 16, 2009 at 05:02:36PM -0500, Chas Williams (CONTRACTOR) wrote:
> that doesnt seem to make sense either. the original code
> is:
>
> for (i = 128; i != 0; i >>= 1) { /* write command out */
> ...
> tmp = (lanai->conf1 & ~CONFIG1_PROMDATA) |
> (data & i) ? CONFIG1_PROMDATA : 0;
>
> since i is always positive here, you wouldnt need the ?: if your suggested
> fix is the original intent. it looks like setting CONFIG1_PROMDATA
> means '1' and not setting it means '0' when writing the value of data
> to the register.
What the hell does it have to do with i being positive? || variant is,
of course, silly; it's very obvious what's going on here. Garden-variety
bit-banging, IOW
tmp = (lanai->conf1 & ~CONFIG1_PROMDATA) |
((data & i) ? CONFIG1_PROMDATA : 0);
and while you technically only need parens around ?:, in this case it's
better to keep it fully parenthesised - more readable that way.
The lack of parens around ?: in the current tree is an obvious bug.
next prev parent reply other threads:[~2009-02-16 22:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-15 16:07 [PATCH] ATM: misplaced parentheses? Roel Kluin
2009-02-16 22:02 ` Chas Williams (CONTRACTOR)
2009-02-16 22:30 ` Al Viro [this message]
2009-02-17 9:59 ` Roel Kluin
2009-02-19 1:41 ` David Miller
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=20090216223001.GW28946@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=akpm@linux-foundation.org \
--cc=chas3@users.sourceforge.net \
--cc=netdev@vger.kernel.org \
--cc=roel.kluin@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 NNTP newsgroup(s).