Re: Decimal Floating Point

From	"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: Decimal Floating Point
Date	2021-09-12 13:08 -0700
Organization	Aioe.org NNTP Server
Message-ID	<shlmoe$292$1@gioia.aioe.org> (permalink)
References	<2bff66f3-391b-4785-9c43-1f056106d6a1n@googlegroups.com>

Show all headers | View raw

On 9/10/2021 6:35 AM, Fabian Russell wrote:
> Decimal floating point was standardized as IEEE758-2008 and new C types
> were defined: _Decimal128, _Decimal64, and _Decimal32.
> 
> Gcc has many built-in functions (via libgcc) to handle decimal FP:
> 
> https://gcc.gnu.org/onlinedocs/gccint/Decimal-float-library-routines.html
> 
> However, what puzzles me is that C has not yet incorporated the decimal
> FP types so that the ordinary binary operators, such as "+ - * /" can operate
> directly on them.  Rather, to add two _Decimal_64 values, x, y, for example,
> one must use the function __bid_adddd3(x, y) instead of x + y.
> 
> Why bother to include the new types yet now allow them to be used
> arithmetically like all other standard numeric types?
> 

Fwiw, here is a project I am working on from time to time that could 
"benefit" from a standardized arbitrary precision decimal lib in C/C++. 
It involves storing information in the n-ary roots of complex numbers, 
in the form of Julia sets. The generating technique involves mapping 
symbols to the roots of a Julia set during iteration. Here is a crude 
example using decimal.js:

http://fractallife247.com/test/rifc_cipher/

For instance, my name is contained within the following complex number 
using the default secret key:

real: 
(-0.70928383564905214400492596591643890200098992164665980782966227733203960188288097070737389345985516069300117982413622497654113697)

imag: 
(0.75006448767684071252250616852543657203512420946592887596427538863664520584158627985390890157772176873489867565028334553930789721)

I am doing this just for fun; to prove that data can be stored in an 
escape time fractal. Fwiw, here is an impl in C++:

https://github.com/ChrisMThomasson/fractal_cipher/blob/master/RIFC/cpp/ct_rifc_sample.cpp

Thread

Decimal Floating Point Fabian Russell <fr314159@gmail.com> - 2021-09-10 06:35 -0700
  Re: Decimal Floating Point "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-09-10 08:17 -0700
    Re: Decimal Floating Point scott@slp53.sl.home (Scott Lurndal) - 2021-09-10 15:44 +0000
      Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-10 12:06 -0400
        Re: Decimal Floating Point Manfred <noname@add.invalid> - 2021-09-10 18:09 +0200
          Re: Decimal Floating Point Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-09-10 16:23 +0000
          Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-10 12:37 -0400
        Re: Decimal Floating Point Fabian Russell <fr314159@gmail.com> - 2021-09-10 09:38 -0700
          Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-10 12:58 -0400
        Re: Decimal Floating Point Eli the Bearded <*@eli.users.panix.com> - 2021-09-10 18:11 +0000
          Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-10 12:13 -0700
            Re: Decimal Floating Point Fabian Russell <fr314159@gmail.com> - 2021-09-10 14:52 -0700
            Re: Decimal Floating Point Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-09-11 07:09 -0700
          Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-10 23:23 -0400
        Re: Decimal Floating Point scott@slp53.sl.home (Scott Lurndal) - 2021-09-10 19:04 +0000
          Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-10 23:23 -0400
            Re: Decimal Floating Point Manfred <noname@add.invalid> - 2021-09-18 19:20 +0200
              Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-20 00:16 -0400
    Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-10 11:14 -0700
      Re: Decimal Floating Point Bart <bc@freeuk.com> - 2021-09-10 23:50 +0100
        Re: Decimal Floating Point David Brown <david.brown@hesbynett.no> - 2021-09-11 20:22 +0200
          Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-11 15:37 -0700
            Re: Decimal Floating Point David Brown <david.brown@hesbynett.no> - 2021-09-12 12:58 +0200
      Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-10 17:36 -0700
  Re: Decimal Floating Point Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-10 18:04 +0200
  Re: Decimal Floating Point Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-10 18:06 +0200
    Re: Decimal Floating Point Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-09-10 09:37 -0700
      Re: Decimal Floating Point Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-10 20:43 +0200
    Re: Decimal Floating Point "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-09-10 09:52 -0700
      Re: Decimal Floating Point Fabian Russell <fr314159@gmail.com> - 2021-09-10 10:08 -0700
        Re: Decimal Floating Point antispam@math.uni.wroc.pl - 2021-09-11 00:36 +0000
    Re: Decimal Floating Point scott@slp53.sl.home (Scott Lurndal) - 2021-09-10 19:07 +0000
      Re: Decimal Floating Point Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 06:31 +0200
        Re: Decimal Floating Point Siri Cruise <chine.bleu@yahoo.com> - 2021-09-10 23:29 -0700
          Re: Decimal Floating Point Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 16:31 +0200
            Re: Decimal Floating Point Barry Schwarz <schwarzb@delq.com> - 2021-09-11 10:04 -0700
            Re: Decimal Floating Point James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-11 15:08 -0400
              Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-11 15:39 -0700
                Re: Decimal Floating Point Richard Damon <Richard@Damon-Family.org> - 2021-09-11 19:28 -0400
  Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-10 11:21 -0700
  Re: Decimal Floating Point Philipp Klaus Krause <pkk@spth.de> - 2021-09-10 23:29 +0200
  Re: Decimal Floating Point Kaz Kylheku <563-365-8930@kylheku.com> - 2021-09-11 16:59 +0000
    Re: Decimal Floating Point Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-11 16:05 -0700
      Re: Decimal Floating Point Kaz Kylheku <563-365-8930@kylheku.com> - 2021-09-14 16:25 +0000
  Re: Decimal Floating Point "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-09-12 13:08 -0700
  Re: Decimal Floating Point Thomas David Rivers <rivers@dignus.com> - 2021-09-13 22:23 -0400

csiph-web