From: Chase Douglas <chase.douglas@canonical.com>
To: Michael Poole <mdpoole@troilus.org>
Cc: Ping Cheng <pinglinux@gmail.com>, Jiri Kosina <jkosina@suse.cz>,
linux-input@vger.kernel.org
Subject: Re: [PATCH] hid-magicmouse: Correct parsing of large X and Y motions.
Date: Mon, 05 Jul 2010 16:51:58 -0400 [thread overview]
Message-ID: <1278363118.10426.15.camel@cndougla> (raw)
In-Reply-To: <87wrt9acu5.fsf@troilus.org>
On Mon, 2010-07-05 at 16:33 -0400, Michael Poole wrote:
> C99 says that the result of right-shifting a negative value is
> compiler-defined. gcc documents that it ensures sign extension. Other
> parts of hid-magicmouse.c use this idiom already. The corresponding
> idiom in hid-core.c (see the snto32() function) would look something
> like this:
>
> x = ((data[3] & 0x0c) << 6) | data[1];
> x |= (x & (1 << 9)) ? (-1 << 10) : 0;
snto32() seems like something we should be using in hid-magicmouse.c? On
further thought, it actually seems like something that should be a macro
in linux/kernel.h. I would think there could be utility for it in many
places of the kernel.
-- Chase
next prev parent reply other threads:[~2010-07-05 20:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-05 14:50 [PATCH] hid-magicmouse: Correct parsing of large X and Y motions Michael Poole
2010-07-05 16:28 ` Chase Douglas
2010-07-11 21:07 ` Jiri Kosina
2010-07-05 19:54 ` Ping Cheng
2010-07-05 20:02 ` Chase Douglas
2010-07-05 20:33 ` Michael Poole
2010-07-05 20:51 ` Chase Douglas [this message]
2010-07-05 22:08 ` Michael Poole
2010-07-05 22:25 ` Chase Douglas
2010-07-06 11:23 ` ext-phil.2.carmody
2010-07-06 11:38 ` Datta, Shubhrajyoti
2010-07-06 11:55 ` Michael Poole
2010-07-06 13:05 ` ext-phil.2.carmody
2010-07-05 22:51 ` Dmitry Torokhov
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