Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD

!MAILaRCHIVE_VOTE_RePLACE
Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
To: Timur Tabi <timur@...>
Cc: Andreas Schwab <schwab@...>, Jan Engelhardt <jengelh@...>, Linux Kernel Mailing List <linux-kernel@...>
Date: Friday, October 5, 2007 - 4:34 pm

On Fri, 5 Oct 2007, Timur Tabi wrote:


   What does it mean for a C-level bitfield ordering to be little-endian if the
   processor is BIG_ENDIAN?

It makes no sense because a bitfield is something having to
do with a 'C' compiler and it must NEVER be used as a template
to address hardware! 'C' gives no guarantee of the ordering
within machine words. The only way you can access them is
using 'C'. They don't have addresses like other objects
(of course they do exist --somewhere). They are put into
"storage units," according to the standard, and these
storage units are otherwise undefined although you can
align them (don't go there).

If you want to call machine-control bits by name, just
define them as hexadecimal numbers (unsigned ints) and,
if your hardware is for both little/big endian, use
a macro that resolves the issue between the number
and the hardware.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.59 BogoMips).
My book : http://www.AbominableFirebug.com/
_


****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.
-
Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

Messages in current thread:
__LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 2:27 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Jan Engelhardt, (Fri Oct 5, 2:35 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 3:35 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Anton Altaparmakov, (Fri Oct 5, 5:06 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 5:10 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Lennart Sorensen, (Tue Oct 9, 1:46 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Tue Oct 9, 1:56 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Krzysztof Halasa, (Tue Oct 9, 2:50 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Jeremy Fitzhardinge, (Tue Oct 9, 3:11 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Krzysztof Halasa, (Tue Oct 9, 3:39 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Jeremy Fitzhardinge, (Tue Oct 9, 5:40 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Krzysztof Halasa, (Tue Oct 9, 6:34 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, linux-os (Dick Johnson), (Wed Oct 10, 8:05 am)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Tue Oct 9, 2:57 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Krzysztof Halasa, (Tue Oct 9, 3:37 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Tue Oct 9, 3:44 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Krzysztof Halasa, (Tue Oct 9, 6:11 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Lennart Sorensen, (Tue Oct 9, 2:34 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Andreas Schwab, (Fri Oct 5, 5:29 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 5:32 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Andreas Schwab, (Fri Oct 5, 7:17 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Jan Engelhardt, (Fri Oct 5, 3:43 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 3:47 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Andreas Schwab, (Fri Oct 5, 4:04 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 4:07 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Andreas Schwab, (Fri Oct 5, 5:17 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, linux-os (Dick Johnson), (Fri Oct 5, 4:34 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Timur Tabi, (Fri Oct 5, 4:37 pm)
Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD, Benjamin Herrenschmidt, (Fri Oct 5, 7:27 pm)