Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview?
03-18-2014, 03:23 PM
Post: #92
 Thomas Okken Senior Member Posts: 1,260 Joined: Feb 2014
RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview?
(03-18-2014 07:16 AM)Werner Wrote:  On a real 42S, LOG(9.99999999999) = 1, exactly. Meaning it is the closest number to the exact result. The same holds for any precision. On Free42 Decimal-34, LOG(1e34-1) is 34 and LOG(1e33-1) is 33, exactly, and that's what the result should be.

Good point. I don't want to return incorrect results just for the convenience of a flawed algorithm!
OK, I'll fix LOG like this: use the bid128_ilogb and bid128_scalbn functions to pull out the exponent and normalize the mantissa to the range [1, 10), then use bid128_log10 on the normalized mantissa, and finally add the exponent to the result. That will return exact results for powers of ten, without introducing numerical inconsistencies.
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 Messages In This Thread Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Thomas Okken - 02-24-2014, 12:09 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 02-24-2014, 01:47 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 02-24-2014, 02:33 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 02-24-2014, 06:45 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview - walter b - 02-24-2014, 06:55 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 02-24-2014, 12:51 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - john jensen - 02-24-2014, 06:44 PM RE: Free42 with IEEE 754-2008 decimal floating-point - Thomas Klemm - 02-24-2014, 07:54 PM Addendum: Free42 with IEEE 754-2008 decimal floating-point - Thomas Klemm - 02-24-2014, 08:41 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 02-25-2014, 12:10 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 02-24-2014, 10:12 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Thomas Okken - 02-25-2014, 12:19 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Massimo Gnerucci - 02-25-2014, 07:31 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Marcus von Cube - 02-25-2014, 09:51 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 02-26-2014, 12:22 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 02-26-2014, 12:42 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 02-26-2014, 01:20 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 02-26-2014, 04:18 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 02-26-2014, 10:15 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-01-2014, 09:14 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Gerson W. Barbosa - 03-01-2014, 11:24 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 12:55 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 09:19 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Gerson W. Barbosa - 03-02-2014, 10:49 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 11:01 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 12:47 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-02-2014, 08:45 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview - J-F Garnier - 03-02-2014, 10:22 AM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - J-F Garnier - 03-02-2014, 08:11 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - J-F Garnier - 03-02-2014, 09:37 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-02-2014, 09:42 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Gerson W. Barbosa - 03-04-2014, 03:10 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-02-2014, 11:06 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - walter b - 03-02-2014, 11:25 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-02-2014, 11:35 AM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - J-F Garnier - 03-02-2014, 02:45 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-02-2014, 06:26 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 08:14 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-02-2014, 09:57 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 10:59 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-03-2014, 06:25 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014, 11:09 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-03-2014, 08:29 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-03-2014, 03:03 PM Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-03-2014, 02:51 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Mike T. - 03-03-2014, 10:57 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-04-2014, 09:17 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - walter b - 03-04-2014, 09:27 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - J-F Garnier - 03-04-2014, 10:03 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - walter b - 03-04-2014, 06:46 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-04-2014, 10:10 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-04-2014, 09:35 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-04-2014, 10:03 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-06-2014, 01:06 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-06-2014, 08:23 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-08-2014, 11:55 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-09-2014, 09:37 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-09-2014, 09:58 PM Free42 1.5 for Windows, Linux, and OS X released - Thomas Okken - 03-10-2014, 12:50 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-10-2014, 08:48 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-10-2014, 09:11 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-10-2014, 11:52 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-15-2014, 11:54 PM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-16-2014, 01:45 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-16-2014, 02:18 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-16-2014, 02:52 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-17-2014, 11:40 AM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-18-2014, 08:08 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-18-2014, 08:51 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-25-2014, 08:48 AM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-16-2014, 02:38 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-16-2014, 03:06 PM Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Thomas Klemm - 03-17-2014, 10:03 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-18-2014, 01:03 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-17-2014, 01:01 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - J-F Garnier - 03-17-2014, 11:08 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-17-2014, 01:29 PM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-18-2014, 12:55 AM RE:Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-18-2014, 07:16 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - J-F Garnier - 03-18-2014, 07:57 AM RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-18-2014 03:23 PM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Werner - 03-18-2014, 09:22 AM RE: Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview? - Paul Dale - 03-18-2014, 09:49 AM

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