Re: Decimal Floating Point

From	Kaz Kylheku <563-365-8930@kylheku.com>
Newsgroups	comp.lang.c
Subject	Re: Decimal Floating Point
Date	2021-09-11 16:59 +0000
Organization	A noiseless patient Spider
Message-ID	<20210911095104.367@kylheku.com> (permalink)
References	<2bff66f3-391b-4785-9c43-1f056106d6a1n@googlegroups.com> <decimal-20210910150340@ram.dialup.fu-berlin.de>

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On 2021-09-10, Stefan Ram <ram@zedat.fu-berlin.de> wrote:
> Fabian Russell <fr314159@gmail.com> writes:
>>Why bother to include the new types yet now allow them to be used
>>arithmetically like all other standard numeric types?
>
>   One would have to define many new rules for cases like
>   "double + decimal" and so on. And these would have to be

This cn be handled via, say, a general decimal contagion rule.
The double operand is converted to the best approximation in decimal
floating point, or undefined behavior if it is out of range.  Then the
calculation proceeds as decimal <op> decimal.

This does not require a large expenditure of words, or their
proliferation.

>   worded conditionally to support systems that do not support
>   such decimal types.

That just requires an indication in one place in the document that
the type is optional, and thus implementations can omit all requirements
pertaining to that type.

It's just like making uint64_t or VLA's optional.

An implementation which has no decimal type simply cannot process
decimal * double. The requirements for how that multiplication is done
do not have to be polluted with conditional text. Just any requirements
involving decimal do not apply according to that type being optional.

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal

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

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