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Groups > comp.lang.forth > #135337
| From | Krishna Myneni <krishna.myneni@ccreweb.org> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: kForth-Win32 fix for decimal string to double float conversion |
| Date | 2026-08-11 07:24 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <115f496$3vfs9$1@dont-email.me> (permalink) |
| References | <113lcfk$18opt$1@dont-email.me> |
On 7/20/26 09:48, Krishna Myneni wrote: ... > "Correctly Rounded Binary-Decimal and Decimal-Binary Conversions," David > M. Gay, Numerical Analysis Manuscript 90-10, AT&T Bell Laboratories, 30 > November 1990. > > and the corresponding code, dtoa.c, link below, which provides a high- > quality strtod() replacement function for decimal string to binary > floating point conversions, as well as the inverse function, dtoa(). > > https://netlib.org/fp/dtoa.c > > The kForth system test code, fpio-test.4th, may be used to identify > problems with decimal string conversion to IEEE double floats in other > Forth systems. The test file may be found at the link below. > > https://github.com/mynenik/kForth-Win32/blob/master/forth-src/system- > test/fpio-test.4th > ... I recently found a paper by Vern Paxson, a student of William Kahan, "A Program for Testing IEEE Decimal-Binary Conversion," 22 May 1991. This nicely written paper was apparently written for a CS class. It contains tables for "difficult" Decimal -> Binary conversions and for Binary -> Decimal conversions, with difficult meaning the required extra arithmetic precision over the starting precision (53 bits) in order to convert to the nearest double precision floating point which can be represented. For example, Table 1. indicates that converting the double-precision floating point number, 4891559871276714924261E+222 requires an arithmetic precision of 53 + 86 = 139 bits. The paper may be found at https://www.icir.org/vern/papers/testbase-report.pdf I am in the process of updating fpio-test.4th to include the conversion "stress tests" from Tables 1 through 4 of the paper. The Forth big number arithmetic code (FSL #47) may be used to check that the binary values of the significand and exponent (power of 2) are correct for decimal to binary conversions. -- Krishna
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kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-20 09:48 -0500
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-21 11:40 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-21 06:20 -0500
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-25 16:08 +0200
Re: kForth-Win32 fix for decimal string to double float conversion peter <peter.noreply@tin.it> - 2026-07-25 17:07 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-25 13:22 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-25 13:30 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-25 13:17 -0500
Re: kForth-Win32 fix for decimal string to double float conversion dxf <dxforth@gmail.com> - 2026-07-26 13:15 +1000
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-26 07:18 -0500
Re: kForth-Win32 fix for decimal string to double float conversion dxf <dxforth@gmail.com> - 2026-07-31 14:54 +1000
Re: kForth-Win32 fix for decimal string to double float conversion anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-07-31 08:35 +0000
Re: kForth-Win32 fix for decimal string to double float conversion albert@spenarnc.xs4all.nl - 2026-07-31 12:05 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-31 07:54 -0500
Re: kForth-Win32 fix for decimal string to double float conversion anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-07-31 16:55 +0000
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-31 14:40 -0500
Re: kForth-Win32 fix for decimal string to double float conversion anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-08-01 08:23 +0000
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-01 06:42 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-21 11:30 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-21 14:47 -0500
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-25 23:42 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-25 18:47 -0500
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-26 13:11 +0200
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-26 13:22 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-26 07:23 -0500
Re: kForth-Win32 fix for decimal string to double float conversion albert@SPENARNC.XS4ALL.NL - 2026-07-26 20:13 +0200
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-07-27 12:20 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-11 07:24 -0500
Re: kForth-Win32 fix for decimal string to double float conversion Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-08-24 18:55 -0500
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