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Groups > comp.lang.c > #93841

Re: Portable 16 bit binary integer write

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Portable 16 bit binary integer write
Date 2016-09-20 09:45 +0200
Organization A noiseless patient Spider
Message-ID <nrqpdv$egf$1@dont-email.me> (permalink)
References (18 earlier) <ln60psyh1n.fsf@kst-u.example.com> <nro59m$ktj$1@dont-email.me> <lnshsvwxte.fsf@kst-u.example.com> <nrpgro$d3u$1@dont-email.me> <5299a08d-ac1e-4a51-a672-216c9d6e3516@googlegroups.com>

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On 19/09/16 23:32, supercat@casperkitty.com wrote:
> On Monday, September 19, 2016 at 3:12:53 PM UTC-5, David Brown wrote:
>> There are some 32-bit architectures that are a little slower for some 
>> 8-bit and 16-bit operations - such as the DEC alpha (I think) and older 
>> ARM designs.  I'd class these devices as obsolete, however.
> 
> The 32-bit ARM processors have no operations other than loads and stores
> that operate on values smaller than 32 bits, and they're hardly obsolete.

The older and (IMHO obsolete) ARM devices I was referring to have no
operations for loading or storing 8-bit or 16-bit values.  So storing a
value smaller than 32-bit was slow - the processor would load in the
previous 32-bit block, use masking and shifting to insert the new 8 or
16 bit value, then store the 32-bit block again.

Modern ARMs are quite happy with operations on smaller values.  The
reason they don't have "8-bit add" instructions is that they are not
needed - they only have 8-bit and 16-bit instructions when such
instructions are different from the 32-bit instructions.  (There would
be a difference in the way some flags are updated, but that is usually
irrelevant, and it is not worth the cost in instruction code space.)

Where smaller size matters, ARMs support them.  They even have
instructions for treating a 32-bit register as a pair of 16-bit values
or a quad of 8-bit values that can be added to another pair or quad as a
single operation.

> If anything, it is the idea that processors should operate on types smaller
> than their natural word size (except for loads and stores) which is obsolete.

Modern processors and modern compilers work together to give you
efficient code regardless of the size of the operand.

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Thread

Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-10 14:23 -0700
  Re: Portable 16 bit binary integer write Barry Schwarz <schwarzb@dqel.com> - 2016-09-10 17:11 -0700
  Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-11 07:00 -0700
  Re: Portable 16 bit binary integer write Richard Damon <Richard@Damon-Family.org> - 2016-09-13 08:41 -0400
    Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-13 06:24 -0700
      Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-13 16:19 +0200
        Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-13 10:20 -0700
          Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-13 11:07 -0700
        Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-13 20:47 -0700
          Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-14 08:24 -0700
            Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 12:17 -0700
          Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-15 11:27 +0200
            Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-15 09:03 -0700
              Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-15 11:21 -0700
              Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-15 18:39 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-15 12:26 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-15 23:12 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-15 16:17 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-15 18:35 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-16 11:10 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-16 08:43 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-16 19:59 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-16 13:34 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-16 16:23 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-16 15:31 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-16 19:06 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-16 23:27 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-17 15:04 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-17 20:35 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 00:09 -0700
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-18 19:36 +0100
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 15:29 -0700
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-19 01:20 +0100
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-18 09:48 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-18 19:38 +0200
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-18 15:33 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-18 13:58 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-18 14:15 -0700
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-18 23:15 +0100
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-18 15:46 -0700
                Re: Portable 16 bit binary integer write Ian Collins <ian-news@hotmail.com> - 2016-09-19 17:03 +1200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-19 07:40 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 10:54 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 10:51 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 22:03 +0200
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 15:44 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-20 09:02 +0200
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-19 21:12 +0100
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 15:58 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 09:49 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-19 02:37 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 13:20 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-19 06:22 -0700
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-19 12:46 +0100
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 16:20 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-19 07:32 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 11:26 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-19 09:10 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-19 09:33 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-19 11:54 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 22:14 +0200
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-19 22:12 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-19 14:32 -0700
                Re: Portable 16 bit binary integer write Robert Wessel <robertwessel2@yahoo.com> - 2016-09-19 22:58 -0500
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-20 09:45 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-20 07:49 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-20 19:43 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-20 11:15 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-19 22:36 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 21:30 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-22 23:58 -0700
                Re: Portable 16 bit binary integer write Ian Collins <ian-news@hotmail.com> - 2016-09-23 19:45 +1200
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 08:17 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-28 09:59 -0700
                Re: Portable 16 bit binary integer write Ian Collins <ian-news@hotmail.com> - 2016-09-29 07:59 +1300
                Re: Portable 16 bit binary integer write Ike Naar <ike@iceland.freeshell.org> - 2016-09-28 19:26 +0000
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-28 12:37 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-09 03:46 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-18 13:53 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-21 21:03 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-21 22:23 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-22 08:09 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 10:31 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-23 10:56 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-29 08:03 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-30 07:39 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-22 09:49 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-22 08:34 -0700
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-22 17:44 +0100
                Re: Portable 16 bit binary integer write Melzzzzz <Melzzzzz@zzzzz.com> - 2016-09-22 17:16 +0000
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-22 18:26 +0100
                Re: Portable 16 bit binary integer write Melzzzzz <Melzzzzz@zzzzz.com> - 2016-09-22 17:33 +0000
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-23 10:23 +0200
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-23 13:43 +0100
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-23 14:58 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-22 18:14 -0700
                Re: Portable 16 bit binary integer write luser droog <luser.droog@gmail.com> - 2016-09-22 20:28 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-23 00:12 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-22 10:57 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-23 10:18 +0200
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 11:48 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-23 15:58 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-29 08:21 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-30 07:42 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-23 23:38 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-24 11:42 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-24 14:13 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-24 23:03 -0700
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-25 11:29 +0100
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 14:02 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-25 15:17 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 16:52 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 13:59 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-25 15:13 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 15:50 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 08:13 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-24 16:06 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-24 11:53 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-24 14:23 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 14:16 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-25 15:18 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-25 16:39 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-25 23:33 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-26 02:08 -0700
                Re: Portable 16 bit binary integer write Richard Heathfield <rjh@cpax.org.uk> - 2016-09-26 10:25 +0100
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-26 03:05 -0700
                Re: Portable 16 bit binary integer write Richard Heathfield <rjh@cpax.org.uk> - 2016-09-26 11:09 +0100
                Re: Portable 16 bit binary integer write "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-09-26 09:29 -0700
                Re: Portable 16 bit binary integer write Richard Heathfield <rjh@cpax.org.uk> - 2016-09-26 17:37 +0100
                Re: Portable 16 bit binary integer write "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-09-26 12:29 -0700
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-26 11:12 +0100
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-26 13:19 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-26 18:34 -0700
                Re: Portable 16 bit binary integer write Ike Naar <ike@iceland.freeshell.org> - 2016-09-27 06:43 +0000
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-27 00:51 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-27 08:42 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-22 11:40 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-23 10:00 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-23 10:34 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-29 08:13 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-18 00:06 +0200
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-17 17:32 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-18 15:57 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-17 20:46 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-18 16:08 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-18 10:03 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-17 23:59 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-17 16:49 -0700
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-18 01:19 +0100
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 07:16 -0700
                Re: Portable 16 bit binary integer write "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-18 10:19 -0400
                Re: Portable 16 bit binary integer write luser droog <luser.droog@gmail.com> - 2016-09-18 13:26 -0700
                Re: Portable 16 bit binary integer write "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-18 17:04 -0400
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-22 01:21 -0700
            Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-15 12:07 -0700
              Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-16 00:32 +0200
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-15 16:30 -0700
                Re: Portable 16 bit binary integer write Keith Thompson <kst-u@mib.org> - 2016-09-15 18:35 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-15 22:00 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-15 22:17 -0700
                Re: Portable 16 bit binary integer write Ian Collins <ian-news@hotmail.com> - 2016-09-16 18:12 +1200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-16 00:46 -0700
                Re: Portable 16 bit binary integer write Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-16 10:23 +0100
                Re: Portable 16 bit binary integer write BartC <bc@freeuk.com> - 2016-09-16 10:59 +0100
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-16 04:13 -0700
                Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-16 08:58 -0700
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-16 10:16 -0700
                Re: Portable 16 bit binary integer write Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-16 09:11 -0700
                Re: Portable 16 bit binary integer write David Brown <david.brown@hesbynett.no> - 2016-09-16 20:14 +0200
                Re: Portable 16 bit binary integer write Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-16 20:37 -0700
      Re: Portable 16 bit binary integer write supercat@casperkitty.com - 2016-09-13 07:47 -0700

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