Re: How to create a 128 bit type in C

From	Robert Wessel <robertwessel2@yahoo.com>
Newsgroups	comp.lang.c
Subject	Re: How to create a 128 bit type in C
Message-ID	<pmjldcdfkf2uanrql9bte7o681pe8564rv@4ax.com> (permalink)
References	(1 earlier) <RbwCA.105388$Hf3.51766@fx37.iad> <obe7np$8bg$1@dont-email.me> <VGxCA.237713$IM7.186175@fx39.iad> <obe9dd$ffh$1@dont-email.me> <c45fb0f1-2330-4455-8697-2a421c052088@googlegroups.com>
Organization	Forte - www.forteinc.com
Date	2017-03-28 16:14 -0500

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On Tue, 28 Mar 2017 12:13:17 -0700 (PDT), Malcolm McLean
<malcolm.mclean5@btinternet.com> wrote:

>On Tuesday, March 28, 2017 at 7:21:26 PM UTC+1, Bart wrote:
>> On 28/03/2017 19:11, Scott Lurndal wrote:
>>
>> > Ok.  They're a gcc extension that has been adopted by icc, pgi,
>> > clang and lcc-win.
>> 
>> So it needed a genius at gcc to figure out that the next step after 
>> 64-bits might be 128?!
>> 
>What are you counting, that you need 128 bits to hold it?
>Oh, it's a scaled integer. What can you measure to an accuracy of one
>part in 2^128?
>That seems to leave Mandelbrots and RSA encryption.

Currency.  At least intermediate results of calculations involving
currency.  And while a full 128 bits isn't usually required, 64 bits
is *not* enough.  And yes, those folks do actually care about the
individual pennies.  And they often have the support of humorless
people with guns who will punish you for not getting it right.

Cobol has required ~64 bit types (actually 18 decimal digits*) for
storage since the early sixties, with longer intermediates.  Recently
that's been changed to require 36 digit storage types.

*Mostly that's independent of the internal format of the type - if you
define your 18 decimal digit field as having a binary format, you'll
get a 64-bit format on most machines.  Or if you specify a BCD-ish
format, you'll usually get 9 or 10 bytes, depending on the
implementation and whether or not the field is signed.

Thread

How to create a 128 bit type in C acidlategamer@gmail.com - 2017-03-28 08:26 -0700
  Re: How to create a 128 bit type in C BartC <bc@freeuk.com> - 2017-03-28 16:42 +0100
    Re: How to create a 128 bit type in C acidlategamer@gmail.com - 2017-03-28 09:15 -0700
      Re: How to create a 128 bit type in C BartC <bc@freeuk.com> - 2017-03-28 19:15 +0100
  Re: How to create a 128 bit type in C Norbert_Paul <norbertpauls_spambin@yahoo.com> - 2017-03-28 17:44 +0200
  Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-28 16:29 +0000
    Re: How to create a 128 bit type in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-03-28 10:52 -0700
      Re: How to create a 128 bit type in C Ike Naar <ike@iceland.freeshell.org> - 2017-03-28 17:55 +0000
        Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 20:17 +0200
          Re: How to create a 128 bit type in C David Brown <david.brown@hesbynett.no> - 2017-03-28 21:17 +0200
      Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-28 18:09 +0000
    Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 19:52 +0200
      Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-28 18:11 +0000
        Re: How to create a 128 bit type in C BartC <bc@freeuk.com> - 2017-03-28 19:21 +0100
          Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 20:29 +0200
            Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-28 18:55 +0000
              Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 21:04 +0200
          Re: How to create a 128 bit type in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-03-28 12:13 -0700
            Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-28 16:14 -0500
              Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-29 13:13 +0000
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-30 00:12 -0500
                Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-30 13:36 +0000
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-30 12:41 -0500
                Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-30 17:55 +0000
                Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-30 17:59 +0000
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-04-01 00:42 -0500
                Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-04-03 13:37 +0000
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-04-03 17:38 -0500
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-04-03 17:49 -0500
                Re: How to create a 128 bit type in C Keith Thompson <kst-u@mib.org> - 2017-04-03 17:43 -0700
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-04-03 20:39 -0500
                Re: How to create a 128 bit type in C Richard Heathfield <rjh@cpax.org.uk> - 2017-04-04 07:00 +0100
        Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 20:28 +0200
          Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-28 16:37 -0500
            Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 23:56 +0200
              Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-28 18:36 -0500
                Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-29 01:43 +0200
                Re: English grammar, nonrestrictive clause Noob <root@127.0.0.1> - 2017-03-31 21:24 +0200
                Re: English grammar, nonrestrictive clause jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-31 21:51 +0200
                Re: English grammar, nonrestrictive clause Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-01 12:34 +0100
            Re: How to create a 128 bit type in C supercat@casperkitty.com - 2017-03-28 15:11 -0700
              Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-28 19:30 -0500
            Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-29 13:19 +0000
              Re: How to create a 128 bit type in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-03-29 14:42 +0100
                Re: How to create a 128 bit type in C scott@slp53.sl.home (Scott Lurndal) - 2017-03-29 15:12 +0000
                Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-30 00:26 -0500
              Re: How to create a 128 bit type in C Robert Wessel <robertwessel2@yahoo.com> - 2017-03-30 00:42 -0500
      Re: How to create a 128 bit type in C Keith Thompson <kst-u@mib.org> - 2017-03-28 11:40 -0700
      Re: How to create a 128 bit type in C Keith Thompson <kst-u@mib.org> - 2017-03-28 11:40 -0700
        Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 20:48 +0200
          Re: How to create a 128 bit type in C Keith Thompson <kst-u@mib.org> - 2017-03-28 12:05 -0700
            Re: How to create a 128 bit type in C Richard Heathfield <rjh@cpax.org.uk> - 2017-03-28 20:13 +0100
              Re: How to create a 128 bit type in C jacobnavia <jacob@jacob.remcomp.fr> - 2017-03-28 21:43 +0200
                Re: Thunderbird charset Noob <root@127.0.0.1> - 2017-03-31 21:38 +0200
    Re: How to create a 128 bit type in C David Brown <david.brown@hesbynett.no> - 2017-03-28 21:19 +0200
  Re: How to create a 128 bit type in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-03-28 18:15 +0100
  Re: How to create a 128 bit type in C Barry Schwarz <schwarzb@dqel.com> - 2017-03-28 10:27 -0700
  Re: How to create a 128 bit type in C "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-03-28 14:16 -0700
  Re: How to create a 128 bit type in C "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-03-28 17:38 -0700
  Re: How to create a 128 bit type in C Thiago Adams <thiago.adams@gmail.com> - 2017-03-30 05:19 -0700
    Re: How to create a 128 bit type in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-03-30 05:32 -0700
      Re: How to create a 128 bit type in C Thiago Adams <thiago.adams@gmail.com> - 2017-03-30 05:40 -0700

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