Re: How to write this sign function in Delphi.

From	Richard Heathfield <rjh@cpax.org.uk>
Newsgroups	comp.lang.c
Subject	Re: How to write this sign function in Delphi.
Date	2015-09-28 20:04 +0100
Organization	A noiseless patient Spider
Message-ID	<muc2sf$ton$1@dont-email.me> (permalink)
References	(9 earlier) <mub0oi$ije$1@dont-email.me> <mub51i$23e$1@dont-email.me> <lntwqesb25.fsf@kst-u.example.com> <mubv24$d7g$1@dont-email.me> <dv1j0b950h81uovnf0l2he5rvebfh9ec5k@4ax.com>

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On 28/09/15 19:39, Robert Wessel wrote:
> On Mon, 28 Sep 2015 18:59:22 +0100, Richard Heathfield
> <rjh@cpax.org.uk> wrote:
>
<snip>
>>
>> The important question in the present context is: what is the largest
>> integer that double is required to be able to represent precisely, such
>> that all smaller (positive) integers can also be represented?
>>
>> It was my belief that this number is considerably lower than 2^53, but
>> it is now only my opinion. I don't quite see how to get the relevant
>> number from the Linear B description of floating point provided in the
>> Standard.
>
> Since DBL_DIG is required not required to be more than 10, the upper
> bound on that is about (10*10-1), or bit over 33  bits worth.

If we are generous, then, and call it 34, then that's (roughly) 
16000000000 pennies, or $160,000,000, which is a fair amount of cash to 
be carrying around in your wallet, but it is not of such an order of 
magnitude that an accountant would feel justified in being complacent 
about the occasional penny going astray.

> It is,
> however, unclear to me that having a DBL_DIG of 10 is actually
> sufficient to require that all integers 1..(10*10-1) are representable
> exactly.  For conventional FP systems that would seem to be the case,
> but FP formats with non-integer bases, for example, you might have
> very few integers that have an exact representation.

Which takes us right back to ints, or to roll-your-own bignums.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

Thread

How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 20:17 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 20:43 +0200
  Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-21 19:51 +0100
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 23:26 +0200
      Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-21 22:47 +0100
        Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 16:29 +0200
          Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-22 16:11 +0100
            Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-23 11:18 +0200
              Re: How to write this sign function in Delphi. David Brown <david.brown@hesbynett.no> - 2015-09-23 13:01 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 20:53 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 20:54 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 20:58 +0200
    Re: How to write this sign function in Delphi. M Philbrook <jamie_ka1lpa@charter.net> - 2015-09-21 18:15 -0400
      Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-21 15:21 -0700
      Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-21 17:51 -0500
        Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-21 19:15 -0400
          Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-21 23:59 -0500
          Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-22 09:22 -0700
            Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-22 10:32 -0700
            Re: How to write this sign function in Delphi. jt@toerring.de (Jens Thoms Toerring) - 2015-09-22 18:17 +0000
              Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-22 12:25 -0700
                Re: How to write this sign function in Delphi. jt@toerring.de (Jens Thoms Toerring) - 2015-09-22 22:33 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-22 15:52 -0700
            Re: How to write this sign function in Delphi. raltbos@xs4all.nl (Richard Bos) - 2015-09-22 23:09 +0000
              Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-23 09:07 -0700
                Re: How to write this sign function in Delphi. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-09-23 16:55 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-23 10:46 -0700
                Re: How to write this sign function in Delphi. jt@toerring.de (Jens Thoms Toerring) - 2015-09-23 23:18 +0000
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-23 22:29 -0400
                Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-24 11:09 +0100
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-09-27 18:23 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-28 05:20 +0000
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-09-27 23:23 -0700
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-28 09:03 +0100
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-09-28 01:24 -0700
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-28 09:32 +0100
                Re: How to write this sign function in Delphi. Bartc <bc@freeuk.com> - 2015-09-28 10:22 +0100
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-28 11:35 +0100
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-28 10:33 -0700
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-28 18:59 +0100
                Re: How to write this sign function in Delphi. Rosario19 <Ros@invalid.invalid> - 2015-09-28 20:09 +0200
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 13:39 -0500
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-28 20:04 +0100
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 16:43 -0500
                Re: How to write this sign function in Delphi. Martin Shobe <martin.shobe@yahoo.com> - 2015-09-28 18:55 -0500
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 19:31 -0500
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-28 12:16 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-28 14:31 -0700
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 16:47 -0500
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-29 11:54 -0700
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-10-01 00:36 -0500
                Re: How to write this sign function in Delphi. raltbos@xs4all.nl (Richard Bos) - 2015-10-02 10:53 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-02 09:48 -0700
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-10-03 11:27 -0500
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-03 12:32 -0700
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-10-03 11:26 -0500
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 16:46 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-28 14:23 -0700
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 16:52 -0500
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-30 01:39 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-30 12:37 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-30 21:28 +0000
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-30 17:54 -0400
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-01 03:59 +0000
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-10-01 01:42 -0400
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-30 16:20 -0700
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 16:39 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-28 23:23 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-29 09:35 -0700
                Re: How to write this sign function in Delphi. raltbos@xs4all.nl (Richard Bos) - 2015-10-02 11:06 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-02 09:23 -0700
                Re: How to write this sign function in Delphi. Martin Shobe <martin.shobe@yahoo.com> - 2015-10-02 12:07 -0500
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-02 10:47 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-10-02 17:48 -0700
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-10-03 16:46 +0100
                Re: How to write this sign function in Delphi. Martin Shobe <martin.shobe@yahoo.com> - 2015-10-05 10:41 -0500
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-28 15:31 -0400
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 16:40 -0500
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-28 18:17 -0400
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-30 02:49 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-30 06:27 -0700
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-29 10:43 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-28 22:51 +0000
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-30 02:11 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-28 22:48 +0000
                Re: How to write this sign function in Delphi. Robert Wessel <robertwessel2@yahoo.com> - 2015-09-28 22:03 -0500
                Re: How to write this sign function in Delphi. Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-30 01:13 -0700
                Re: How to write this sign function in Delphi. Bartc <bc@freeuk.com> - 2015-09-30 17:06 +0100
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-09-30 17:26 +0100
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-09-30 13:04 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-09-28 09:12 +0000
                Re: How to write this sign function in Delphi. David Brown <david.brown@hesbynett.no> - 2015-09-28 12:28 +0200
                Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-28 20:44 +0100
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-01 01:39 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-10-01 08:55 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-01 09:02 -0700
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-01 14:55 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-01 16:48 -0700
                Re: How to write this sign function in Delphi. raltbos@xs4all.nl (Richard Bos) - 2015-10-02 11:46 +0000
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-06 00:15 -0700
                Re: How to write this sign function in Delphi. Les Cargill <lcargill99@comcast.com> - 2015-10-06 02:43 -0500
                Re: How to write this sign function in Delphi. David Brown <david.brown@hesbynett.no> - 2015-10-06 10:13 +0200
                Re: How to write this sign function in Delphi. Les Cargill <lcargill99@comcast.com> - 2015-10-06 19:14 -0500
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-06 21:36 -0700
                Re: How to write this sign function in Delphi. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-06 09:25 +0100
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-06 09:28 -0700
                Re: How to write this sign function in Delphi. Keith Thompson <kst-u@mib.org> - 2015-10-06 13:11 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-06 13:56 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-07 00:25 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-06 09:44 -0700
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-06 10:08 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-06 12:00 -0700
                Re: How to write this sign function in Delphi. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-07 01:58 -0700
                Re: How to write this sign function in Delphi. Richard Heathfield <rjh@cpax.org.uk> - 2015-10-07 10:12 +0100
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-08 00:40 -0700
                Re: How to write this sign function in Delphi. Philip Lantz <prl@canterey.us> - 2015-10-03 12:29 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-03 13:20 -0700
                Re: How to write this sign function in Delphi. Philip Lantz <prl@canterey.us> - 2015-10-03 12:33 -0700
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-10-03 17:02 -0400
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-03 15:04 -0700
                Re: How to write this sign function in Delphi. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-04 05:12 +0000
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-04 12:58 -0700
                Re: How to write this sign function in Delphi. Philip Lantz <prl@canterey.us> - 2015-10-03 12:37 -0700
                Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-10-03 16:21 -0400
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-03 16:05 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-10-03 14:02 -0700
                Re: How to write this sign function in Delphi. supercat@casperkitty.com - 2015-09-24 09:39 -0700
                Re: How to write this sign function in Delphi. raltbos@xs4all.nl (Richard Bos) - 2015-09-27 16:26 +0000
        Re: How to write this sign function in Delphi. M Philbrook <jamie_ka1lpa@charter.net> - 2015-09-21 22:06 -0400
          Re: How to write this sign function in Delphi. James Kuyper <jameskuyper@verizon.net> - 2015-09-22 10:17 -0400
            Re: How to write this sign function in Delphi. M Philbrook <jamie_ka1lpa@charter.net> - 2015-09-22 19:48 -0400
              Re: How to write this sign function in Delphi. Noob <root@127.0.0.1> - 2015-09-23 13:15 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 21:25 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 21:54 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 22:02 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-21 21:50 +0200
  Re: How to write this sign function in Delphi. M Philbrook <jamie_ka1lpa@charter.net> - 2015-09-21 18:08 -0400
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 08:31 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 10:18 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 10:50 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 11:00 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 11:07 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 11:20 +0200
  Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 11:15 +0200
    Re: How to write this sign function in Delphi. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-22 11:23 +0200

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