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Re: RfD: D>F and S>F first draft

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: RfD: D>F and S>F first draft
Date 2015-11-22 18:26 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2015Nov22.192610@mips.complang.tuwien.ac.at> (permalink)
References <n2qss7$2mo$1@dont-email.me> <fc2fbd3f-00fa-4e6b-ae01-b57080faebae@googlegroups.com> <2015Nov22.170010@mips.complang.tuwien.ac.at> <87ziy6hsja.fsf@nightsong.com>

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Paul Rubin <no.email@nospam.invalid> writes:
>anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:
>>>An ambiguous condition may still exist if the maximum double length
>>> integer exceeds the maximum representable floating point number.
>> I doubt there is any Forth system where that happens, nor is there
>> likely to ever be: in particular, the largest non-infinite value on
>> 32-bit IEEE FP is not quite 2^128,...  And should there ever be a
>> system that uses, say, 8-bit FP values, there is still an FP value that
>> is nearest, so use that!
>
>You mean use the largest FP value even if it's way too small?

Or use an infinity if the FP format supports that.

>That seems worse than crashing.

Seems pretty appropriate to me for an operation that is allowed to
lose precision.  And it's really a question of how many angels can
dance on the head of a pin, as no systems implementor in his right
mind will use such an FP format for the r type in the standard.

>IEEE 754 half-precision (binary16) format has a 5 bit exponent.  I
>believe it's supported by some graphics hardware that might be plausible
>Forth targets.

I don't think that GPUs are a plausible Forth target, but >
>https://en.wikipedia.org/wiki/Half-precision_floating-point_format
anyway, GPUs also have 32-bit floats.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2015: http://www.rigwit.co.uk/EuroForth2015/

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RfD: D>F and S>F  first draft C G Montgomery <cgm@physics.utoledo.edu> - 2015-11-21 17:59 -0500
  Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-22 18:25 +1100
    Re: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 06:20 -0800
      Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-23 10:58 +1100
        Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-23 02:57 +0100
          Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-24 13:16 +1100
            Re: D>F and S>F  first draft Paul Rubin <no.email@nospam.invalid> - 2015-11-23 18:49 -0800
              Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-25 11:51 +1100
                Re: D>F and S>F  first draft Paul Rubin <no.email@nospam.invalid> - 2015-11-24 17:26 -0800
            Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-25 02:43 +0100
              Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-26 12:16 +1100
                Re: D>F and S>F  first draft Paul Rubin <no.email@nospam.invalid> - 2015-11-25 17:47 -0800
                Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-26 15:47 +1100
                Re: D>F and S>F  first draft Paul Rubin <no.email@nospam.invalid> - 2015-11-25 23:07 -0800
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-26 07:27 +0000
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-26 09:19 +0000
                Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-28 04:26 +1100
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-28 11:31 +0000
                Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-11-29 20:23 +1100
                Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-29 20:39 +0100
                Re: D>F and S>F  first draft "HAA" <someone@microsoft.com> - 2015-12-05 17:48 +1100
                Re: D>F and S>F  first draft Julian Fondren <julian.fondren@gmail.com> - 2015-12-04 23:58 -0800
                Re: D>F and S>F  first draft mhx@iae.nl - 2015-12-05 02:19 -0800
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-12-05 11:25 +0000
                Re: D>F and S>F first draft Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-12-05 13:11 +0000
                Re: D>F and S>F  first draft mhx@iae.nl - 2015-12-05 05:27 -0800
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-12-05 15:33 +0000
                Re: D>F and S>F  first draft mhx@iae.nl - 2015-12-07 10:10 -0800
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-12-09 16:58 +0000
                Re: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-12-06 10:23 -0800
                Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-12-06 21:37 +0100
                Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-12-05 19:08 +0100
                Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-30 08:33 +0000
                Re: D>F and S>F first draft "Elizabeth D. Rather" <erather@forth.com> - 2015-11-25 21:43 -1000
                Re: D>F and S>F first draft "HAA" <someone@microsoft.com> - 2015-11-28 19:28 +1100
                Re: D>F and S>F first draft Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-11-26 11:37 +0000
    Re: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-22 15:10 +0000
    Re: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-22 20:48 +0100
      Re: D>F and S>F first draft "Elizabeth D. Rather" <erather@forth.com> - 2015-11-22 13:42 -1000
        Re: D>F and S>F first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-23 11:50 +0000
          Re: D>F and S>F first draft "Elizabeth D. Rather" <erather@forth.com> - 2015-11-23 12:46 -1000
            Forth libraries Lars Brinkhoff <lars.spam@nocrew.org> - 2015-11-24 08:55 +0100
  Re: RfD: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 06:33 -0800
    Re: RfD: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-22 16:00 +0000
      Re: RfD: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 08:53 -0800
        Re: RfD: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 09:11 -0800
        Re: RfD: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-22 18:24 +0000
      Re: RfD: D>F and S>F  first draft Paul Rubin <no.email@nospam.invalid> - 2015-11-22 09:07 -0800
        Re: RfD: D>F and S>F  first draft stephen@mpeforth.com (Stephen Pelc) - 2015-11-22 18:10 +0000
        Re: RfD: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-22 18:26 +0000
          Re: RfD: D>F and S>F first draft rickman <gnuarm@gmail.com> - 2015-11-22 13:58 -0500
            Re: RfD: D>F and S>F first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-23 12:34 +0000
              Re: RfD: D>F and S>F first draft Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-11-23 16:39 +0000
              Re: RfD: D>F and S>F first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-24 03:00 +0100
            Re: RfD: D>F and S>F first draft Lars Brinkhoff <lars.spam@nocrew.org> - 2015-11-23 13:48 +0100
              Re: RfD: D>F and S>F first draft mhx@iae.nl - 2015-11-23 05:19 -0800
                Re: RfD: D>F and S>F first draft mhx@iae.nl - 2015-11-23 16:09 -0800
        Re: RfD: D>F and S>F  first draft Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-22 20:42 +0100
    Re: RfD: D>F and S>F  first draft C G Montgomery <cgm@physics.utoledo.edu> - 2015-11-22 16:43 -0500
      Re: RfD: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 18:40 -0800
        Re: RfD: D>F and S>F  first draft krishna.myneni@ccreweb.org - 2015-11-22 18:51 -0800
        Re: RfD: D>F and S>F  first draft C G Montgomery <cgm@physics.utoledo.edu> - 2015-11-25 15:47 -0500
  Re: RfD: D>F and S>F  first draft anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-22 14:29 +0000
  Re: RfD: D>F and S>F first draft "David N. Williams" <williams@umich.edu> - 2015-11-22 10:41 -0600

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