From: Andreas Schwab <schwab@suse.de>
To: Timur Tabi <timur@freescale.com>
Cc: Jan Engelhardt <jengelh@computergmbh.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD
Date: Fri, 05 Oct 2007 22:04:18 +0200 [thread overview]
Message-ID: <jed4vtnxa5.fsf@sykes.suse.de> (raw)
In-Reply-To: <470694E0.7030408@freescale.com> (Timur Tabi's message of "Fri\, 05 Oct 2007 14\:47\:44 -0500")
Timur Tabi <timur@freescale.com> writes:
> I'm writing a driver that talks to hardware that has a shift register.
> The register can be shifted either left or right, so all the bits
> obviously have to be in order, but it can be either order.
Bit addressing is strictly internal to the cpu, the smallest unit that
the cpu can address externally is a byte. The only place where bit
order matters on the C level is in a bitfield that is overlayed over a
block of memory, but this is not visible outside the cpu.
> What I want to do is to have the driver detect when byte-endianness
> doesn't match bit-endianness when it writes the the word to a
> memory-mapped device.
The bit mapping on your device is strictly internal to the device and
has nothing to do with bit order on the C level.
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
next prev parent reply other threads:[~2007-10-05 20:04 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-05 18:27 __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD Timur Tabi
2007-10-05 18:35 ` Jan Engelhardt
2007-10-05 19:35 ` Timur Tabi
2007-10-05 19:43 ` Jan Engelhardt
2007-10-05 19:47 ` Timur Tabi
2007-10-05 20:04 ` Andreas Schwab [this message]
2007-10-05 20:07 ` Timur Tabi
2007-10-05 20:34 ` linux-os (Dick Johnson)
2007-10-05 20:37 ` Timur Tabi
2007-10-05 23:27 ` Benjamin Herrenschmidt
2007-10-05 21:17 ` Andreas Schwab
2007-10-05 21:06 ` Anton Altaparmakov
2007-10-05 21:10 ` Timur Tabi
2007-10-05 21:29 ` Andreas Schwab
2007-10-05 21:32 ` Timur Tabi
2007-10-05 23:17 ` Andreas Schwab
2007-10-09 17:46 ` Lennart Sorensen
2007-10-09 17:56 ` Timur Tabi
2007-10-09 18:34 ` Lennart Sorensen
2007-10-09 18:50 ` Krzysztof Halasa
2007-10-09 18:57 ` Timur Tabi
2007-10-09 19:37 ` Krzysztof Halasa
2007-10-09 19:44 ` Timur Tabi
2007-10-09 22:11 ` Krzysztof Halasa
2007-10-09 19:11 ` Jeremy Fitzhardinge
2007-10-09 19:39 ` Krzysztof Halasa
2007-10-09 21:40 ` Jeremy Fitzhardinge
2007-10-09 22:34 ` Krzysztof Halasa
2007-10-10 12:05 ` linux-os (Dick Johnson)
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