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| From | Kaz Kylheku <kaz@kylheku.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: formats and endians |
| Date | 2014-12-16 18:35 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <20141216102948.329@kylheku.com> (permalink) |
| References | (2 earlier) <e86ce2b2-32e4-4aad-97d8-4410bb59fae6@googlegroups.com> <448ui7h7um.fsf@be-well.ilk.org> <de2d870a-d33b-4e72-a369-3884076b3021@googlegroups.com> <m6pqpq$p32$1@dont-email.me> <44wq5rfota.fsf@be-well.ilk.org> |
On 2014-12-16, Lowell Gilbert <lgusenet@be-well.ilk.org> wrote:
> Ken Brody <kenbrody@spamcop.net> writes:
>
>> On 12/16/2014 11:47 AM, fir wrote:
>>> W dniu wtorek, 16 grudnia 2014 17:34:20 UTC+1 użytkownik Lowell Gilbert napisał:
>>>> In hardware, both little-endian and big-endian have advantages to the
>>>> designer, so they will co-exist for the foreseeable future. A number of
>>>> CPUs can run in either mode.
>>>>
>>> what is the advantage of little endian? none comes to my mind....
>>
>> What is the advantage of big-endian?
>
> From the hardware point of view, there are a few. Most of them come from
> the fact that it makes instructions for sequential sub-word encodings
> easier to implement; for example, BCD operations are simpler, and
> doing string operations a whole word at a time is also
> easier. Re-ordering bits with a word (primarily useful for DSP) is a lot
> simpler. There are a few more that aren't coming to mind at the moment.
However, note that several "bignum" libraries that I know about use a
little-endian format for storing the digits ("limbs") of the multi-precision
numbers.
The advantage is obvious: if you have two numbers a, and b,
then a[0] and b[0] are the least significant limb, and can be added
together. Then you can take the carry and apply it over to a[1], b[1].
Little endian lines up (places at the same byte and bit offset) the
unit bits, the twos, the fours, the eights, ...
Some operations require working from the other and, like relational
comparison. But the array access can be elided entirely if the numbers are of
unequal length, and it can terminate at the first difference that it finds.
Addition has to iterate through the full length of at least the shorter
of the two numbers.
Multi-precision operations prove the superiority of little endian.
A good reason to invent little endian formats (with alignment) is the
proliferation of little-endian architectures.
You don't want to make millions of smartphones, tablets, laptops and desktop
PC's do byte swapping, so that some minority machines don't have to.
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formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 04:49 -0800
formats and endians John Bode <jfbode1029@gmail.com> - 2014-12-16 05:24 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 05:38 -0800
Re: formats and endians Kleuske <kleuske@nowhere.net> - 2014-12-16 13:55 +0000
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 11:49 -0600
Re: formats and endians BGB <cr88192@hotmail.com> - 2014-12-16 21:37 -0600
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-17 01:08 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-17 02:42 -0800
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-18 14:38 -0600
Re: formats and endians Rosario193 <Rosario@invalid.invalid> - 2014-12-18 23:09 +0100
Re: formats and endians BGB <cr88192@hotmail.com> - 2014-12-18 16:52 -0600
Re: formats and endians Kleuske <kleuske@nowhere.net> - 2014-12-17 11:11 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-17 03:49 -0800
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-18 16:28 -0600
Re: formats and endians BGB <cr88192@hotmail.com> - 2014-12-18 19:38 -0600
Re: formats and endians Kleuske <kleuske@nowhere.net> - 2014-12-21 14:17 +0000
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-22 02:19 -0800
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2015-01-15 12:18 -0600
Re: formats and endians Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-15 22:35 +0000
Re: formats and endians raltbos@xs4all.nl (Richard Bos) - 2015-01-20 16:06 +0000
Re: formats and endians Barry Schwarz <schwarzb@dqel.com> - 2015-01-22 15:41 -0800
Re: formats and endians Robert Wessel <robertwessel2@yahoo.com> - 2015-01-23 00:45 -0600
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2015-01-23 08:52 +0000
Re: formats and endians Robert Wessel <robertwessel2@yahoo.com> - 2015-01-23 05:47 -0600
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-23 03:51 -0800
Re: formats and endians Bartc <bc@freeuk.com> - 2015-01-23 12:18 +0000
Re: formats and endians raltbos@xs4all.nl (Richard Bos) - 2015-01-23 13:49 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2015-01-23 07:02 -0800
Re: formats and endians fmassei@gmail.com - 2015-01-23 07:39 -0800
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2015-01-23 10:38 -0500
Re: formats and endians Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-23 17:45 +0000
Re: formats and endians James Kuyper <jameskuyper@verizon.net> - 2015-01-23 12:59 -0500
Re: formats and endians Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-23 18:30 +0000
Re: formats and endians James Kuyper <jameskuyper@verizon.net> - 2015-01-26 12:35 -0500
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2015-01-26 18:15 +0000
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-26 10:53 -0800
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2015-01-26 19:06 +0000
Re: formats and endians Les Cargill <lcargill99@comcast.com> - 2015-01-26 17:54 -0600
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2015-01-26 19:09 -0600
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2015-01-27 01:49 +0000
Re: formats and endians James Kuyper <jameskuyper@verizon.net> - 2015-01-26 21:37 -0500
Re: formats and endians raltbos@xs4all.nl (Richard Bos) - 2015-01-23 22:33 +0000
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2015-01-23 18:02 +0000
Re: formats and endians Greg Martin <greg.at.softsprocket@dot.com> - 2015-01-23 18:50 +0000
Re: formats and endians glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-24 00:01 +0000
Re: formats and endians raltbos@xs4all.nl (Richard Bos) - 2015-01-24 10:05 +0000
Re: formats and endians glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-24 11:57 +0000
Re: formats and endians Geoff <geoff@invalid.invalid> - 2015-01-24 07:48 -0800
Re: formats and endians Bartc <bc@freeuk.com> - 2015-01-24 10:43 +0000
Re: formats and endians Geoff <geoff@invalid.invalid> - 2015-01-24 07:52 -0800
Re: formats and endians raltbos@xs4all.nl (Richard Bos) - 2015-01-23 13:51 +0000
Re: formats and endians John Bode <jfbode1029@gmail.com> - 2014-12-16 06:56 -0800
Re: formats and endians Robert Wessel <robertwessel2@yahoo.com> - 2014-12-16 13:20 -0600
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 18:00 -0600
Re: formats and endians "Bill Cunningham" <nospam@nspam.invalid> - 2014-12-17 16:32 -0500
Re: formats and endians David Brown <david.brown@hesbynett.no> - 2014-12-16 15:26 +0100
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 06:57 -0800
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-12-16 11:34 -0500
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 08:47 -0800
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 17:02 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 10:49 -0800
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 19:10 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 11:28 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 11:43 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 11:58 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 12:20 -0800
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 20:21 +0000
Re: formats and endians Keith Thompson <kst-u@mib.org> - 2014-12-16 13:08 -0800
Re: formats and endians Richard Heathfield <invalid@see.sig.invalid> - 2014-12-16 21:19 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 13:27 -0800
Re: formats and endians Tim Rentsch <txr@alumni.caltech.edu> - 2014-12-16 16:41 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 13:22 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 14:00 -0800
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 22:26 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 14:54 -0800
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 15:09 -0800
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 20:08 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 12:48 -0800
Re: formats and endians Kaz Kylheku <kaz@kylheku.com> - 2014-12-16 22:21 +0000
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-16 22:39 +0000
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 15:32 -0800
Re: formats and endians glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-17 00:51 +0000
Re: formats and endians BartC <bc@freeuk.com> - 2014-12-17 11:04 +0000
Re: formats and endians glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-17 17:04 +0000
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-12-16 12:29 -0500
Re: formats and endians Ken Brody <kenbrody@spamcop.net> - 2014-12-16 12:40 -0500
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-12-16 13:10 -0500
Re: formats and endians Kaz Kylheku <kaz@kylheku.com> - 2014-12-16 18:35 +0000
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 12:57 -0600
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-12-16 15:11 -0500
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 18:10 -0600
Re: formats and endians fir <profesor.fir@gmail.com> - 2014-12-16 10:51 -0800
Re: formats and endians glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-16 19:43 +0000
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-16 10:37 -0800
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 13:05 -0600
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-16 11:49 -0800
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 17:16 -0600
Re: formats and endians Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-12-16 14:55 -0500
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 17:48 -0600
Re: formats and endians BGB <cr88192@hotmail.com> - 2014-12-17 00:18 -0600
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-20 12:21 -0600
Re: formats and endians BGB <cr88192@hotmail.com> - 2014-12-22 01:38 -0600
Re: formats and endians Stephen Sprunk <stephen@sprunk.org> - 2014-12-16 11:45 -0600
Re: formats and endians Michael Angelo Ravera <maravera@prodigy.net> - 2014-12-18 16:50 -0800
Re: formats and endians Nobody <nobody@nowhere.invalid> - 2014-12-17 04:51 +0000
Re: formats and endians Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-19 10:16 -0800
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