Groups > comp.lang.forth > #135651 > unrolled thread

ddfloat library: the behavior of >dd

Started by	marcel hendrix <mhx@iae.nl>
First post	2026-09-10 19:33 +0200
Last post	2026-09-15 17:53 -0500
Articles	20 on this page of 38 — 4 participants

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  ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-10 19:33 +0200
    Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-10 13:35 -0500
      Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-10 22:10 +0200
        Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-10 16:51 -0500
    Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-11 12:16 +1000
      Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-11 12:05 +0200
        Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-12 00:27 +0200
          Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-11 20:29 -0500
            Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-12 12:02 +1000
              Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-12 10:24 -0500
            Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-12 10:45 +0200
              Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-12 19:51 +1000
              Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-12 22:47 +1000
                Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-13 03:14 +1000
                  Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-12 13:02 -0500
                    Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-13 15:44 +1000
                  Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-13 09:00 +0200
                    Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-13 20:33 +1000
                    Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-14 13:28 +1000
                      Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-14 10:09 +0200
                        Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-14 20:00 +1000
                          Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-14 12:22 +0200
                            Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-14 21:59 +1000
                              Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-14 14:26 +0200
                                Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-15 01:32 +1000
                                  Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-14 21:08 +0200
                                    Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-14 15:25 -0500
                                      Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-15 13:11 +1000
                                        Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-15 14:06 +0200
                                        Re: ddfloat library: the behavior of >dd dxf <dxforth@gmail.com> - 2026-09-16 00:05 +1000
                            Re: ddfloat library: the behavior of >dd anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-09-14 15:00 +0000
                              Re: ddfloat library: the behavior of >dd marcel hendrix <mhx@iae.nl> - 2026-09-14 21:15 +0200
                              Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-14 15:29 -0500
                                Re: ddfloat library: the behavior of >dd anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-09-14 20:58 +0000
                                  Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-15 07:33 -0500
                                    Re: ddfloat library: the behavior of >dd anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-09-15 15:53 +0000
                                      Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-15 15:23 -0500
                                        Re: ddfloat library: the behavior of >dd Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-09-15 17:53 -0500

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#135651 — ddfloat library: the behavior of >dd

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-10 19:33 +0200
Subject	ddfloat library: the behavior of >dd
Message-ID	<117uplc$160ff$1@dont-email.me>

( I'm starting a new thread because "Getting the exponent of an x87 
float" is becoming unwieldy large )

I ported D. Bailey's fp library functions to iForth in 2006. However,
because there was no convenient way to test the accuracy of the 
double-double results, it has been unclear if the result were really 
accurate up to 106 bits, and if not, if there were bugs in my 
implementation.

The most convenient way to test D. Bailey's package is to compare its 
output to MATLAB, because I can then use the vpa() function (a variable 
precision arithmetic package) through iForth's COM interface on Windows.

As this will involve string manipulation I have to make sure the >DD
function is robust. I encounter some problems that may or may not have 
been covered in the "Getting the exponent of an x87 float" thread.

Here is the list so far:
   s" 9999999999999999999999999999999999999999999999999999d0"   >dd 
ddfe. 1.00000000000000001224290705471e50   not ok
   s" 8999999999999999999999999999999999999999999999999999d0"   >dd 
ddfe. 9.00000000000000066309858349023e49   not ok
   s" .9999999999999999999999999999999999999999999999999999d0"  >dd 
ddfe. 1.000000000000000100000000000000e0   not ok
   s" 0.99999999999999999999d44" 			       >dd ddfe. 
1.00000000000000000000208925819e44   not ok
   s" 0.99999999999999999999d34"                                >dd 
ddfe. 1.00000000000000000001814749767e34   not ok
   s" 0.99999999999999999999d30"                                >dd 
ddfe. 9.99999999999999999972820130815e29   not ok
   s" 0.99999999999999999999d28"                                >dd ddfe.
0.99999999999999999999000000000e28   ok
   s" 0.9999999999999999999999999999999999999999999999999999d0" >dd ddfe.
1.000000000000000000000000000000e0   ok
   s" 1.9999999999999999999999999999999999999999999999999999d0" >dd 
ddfe. 2.000000000000000000000000000000e0   ok

... which hints that the exponent should not exceed +30 and that the 
number must start with "[optional sign][0<=digit<9]".

   s" 0.00000000000000000000001d" >dd ddfe. 
1.000000000000000000005091539406e-23  not ok
   s" 0.000000000000000000001d"   >dd ddfe.
0.999999999999999999988259524950e-21  not ok

The mantissa should be smaller than 30 decimals?

   s" 0.0000000000000000001d"     >dd ddfe. 
0.999999999999999999995600113174e-19  not ok
   s" 0.00000000000000001d"       >dd ddfe. 
9.999999999999999999645978009888e-18  not ok
   s" 0.000000000000001d"         >dd ddfe. 
1.000000000000000000000000000000e-15  ok
   s" 0.0000000000000001d"        >dd ddfe. 
9.999999999999999999699073446189e-17  not ok
   s" 1.000000000000000d-16"      >dd ddfe. 
1.000000000000000000028598854846e-16  not ok
   s" 1.000000000000000d-15"      >dd ddfe. 
1.000000000000000000052694643620e-15  not ok
   s" 1.000000000000000d-5"       >dd ddfe. 
1.000000000000000000007126988157e-5   not ok
   s" 1.000000000000000d-1"       >dd ddfe. 
9.999999999999999999661186821098e-2   not ok

... which suggests that a negative exponent (or a number between  0 and 
1e-16) is a problem.

   s" 1e-30"                      >dd ddfe. 
1.000000000000000000000000000000e-30  ok
   s" 1.0e-30"                    >dd ddfe. 
0.999999999999999999986447472844e-30  not ok

... which tells me that there might be a problem when a decimal point is 
used, or that a buffer is overwritten.

If I get reports  that >dd ddfe. processes all of these fine on other 
Forths it may be advantageous to fix >dd ddfe. Otherwise, I'd better go 
straight for the MPFR libraries.

-marcel

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#135652

From	Krishna Myneni <krishna.myneni@ccreweb.org>
Date	2026-09-10 13:35 -0500
Message-ID	<117ut9l$27qcr$1@dont-email.me>
In reply to	#135651

On 9/10/26 12:33 PM, marcel hendrix wrote:
> ( I'm starting a new thread because "Getting the exponent of an x87 
> float" is becoming unwieldy large )
> 
> I ported D. Bailey's fp library functions to iForth in 2006. However,
> because there was no convenient way to test the accuracy of the double- 
> double results, it has been unclear if the result were really accurate 
> up to 106 bits, and if not, if there were bugs in my implementation.
> 
> The most convenient way to test D. Bailey's package is to compare its 
> output to MATLAB, because I can then use the vpa() function (a variable 
> precision arithmetic package) through iForth's COM interface on Windows.
> 
> As this will involve string manipulation I have to make sure the >DD
> function is robust. I encounter some problems that may or may not have 
> been covered in the "Getting the exponent of an x87 float" thread.
> 
> Here is the list so far:
>    s" 9999999999999999999999999999999999999999999999999999d0"   >dd 
> ddfe. 1.00000000000000001224290705471e50   not ok
>    s" 8999999999999999999999999999999999999999999999999999d0"   >dd 
> ddfe. 9.00000000000000066309858349023e49   not ok
>    s" .9999999999999999999999999999999999999999999999999999d0"  >dd 
> ddfe. 1.000000000000000100000000000000e0   not ok
>    s" 0.99999999999999999999d44"                    >dd ddfe. 
> 1.00000000000000000000208925819e44   not ok
>    s" 0.99999999999999999999d34"                                >dd 
> ddfe. 1.00000000000000000001814749767e34   not ok
>    s" 0.99999999999999999999d30"                                >dd 
> ddfe. 9.99999999999999999972820130815e29   not ok
>    s" 0.99999999999999999999d28"                                >dd ddfe.
> 0.99999999999999999999000000000e28   ok
>    s" 0.9999999999999999999999999999999999999999999999999999d0" >dd ddfe.
> 1.000000000000000000000000000000e0   ok
>    s" 1.9999999999999999999999999999999999999999999999999999d0" >dd 
> ddfe. 2.000000000000000000000000000000e0   ok
> 
> ... which hints that the exponent should not exceed +30 and that the 
> number must start with "[optional sign][0<=digit<9]".

The exponent range for double double numbers is the same as for ordinary 
double precision: 10^-308 to 10^+308. Because there are only about 31 
decimal digits of precision, it is possible to enter all numbers with at 
most 32 digits followed by a decimal exponent. In double precision, 
there are 16 decimal digits of precision and 17 decimal digits are 
enough to specify any number which can be represented.

> 
>    s" 0.00000000000000000000001d" >dd ddfe. 
> 1.000000000000000000005091539406e-23  not ok
>    s" 0.000000000000000000001d"   >dd ddfe.
> 0.999999999999999999988259524950e-21  not ok
> 
> The mantissa should be smaller than 30 decimals?
> 

>    s" 0.0000000000000000001d"     >dd ddfe. 
> 0.999999999999999999995600113174e-19  not ok
>    s" 0.00000000000000001d"       >dd ddfe. 
> 9.999999999999999999645978009888e-18  not ok
>    s" 0.000000000000001d"         >dd ddfe. 
> 1.000000000000000000000000000000e-15  ok
>    s" 0.0000000000000001d"        >dd ddfe. 
> 9.999999999999999999699073446189e-17  not ok
>    s" 1.000000000000000d-16"      >dd ddfe. 
> 1.000000000000000000028598854846e-16  not ok
>    s" 1.000000000000000d-15"      >dd ddfe. 
> 1.000000000000000000052694643620e-15  not ok
>    s" 1.000000000000000d-5"       >dd ddfe. 
> 1.000000000000000000007126988157e-5   not ok
>    s" 1.000000000000000d-1"       >dd ddfe. 
> 9.999999999999999999661186821098e-2   not ok
> 
> ... which suggests that a negative exponent (or a number between  0 and 
> 1e-16) is a problem.
> 
>    s" 1e-30"                      >dd ddfe. 
> 1.000000000000000000000000000000e-30  ok
>    s" 1.0e-30"                    >dd ddfe. 
> 0.999999999999999999986447472844e-30  not ok
> 
> ... which tells me that there might be a problem when a decimal point is 
> used, or that a buffer is overwritten.
> 
The term "mantissa" is a bit ambiguous, and people seem to use 
"significand" which in scientific notation consists of the single digit 
preceding the decimal point, followed by all significant digits trailing 
the decimal point.

https://en.wikipedia.org/wiki/Significand


> If I get reports  that >dd ddfe. processes all of these fine on other 
> Forths it may be advantageous to fix >dd ddfe. Otherwise, I'd better go 
> straight for the MPFR libraries.

There's a huge speed advantage for double double precision arithmetic 
over multi-precision when 106 bit significand and the exponent range of 
ordinary double precision suffices. IMO, it's worth having a usable 
Forth library for double double arithmetic.

--
Krishna

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#135653

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-10 22:10 +0200
Message-ID	<117v2rm$2aaas$1@dont-email.me>
In reply to	#135652

On 9/10/2026 8:35 PM, Krishna Myneni wrote:
> 
>> If I get reports  that >dd ddfe. processes all of these fine on other 
>> Forths it may be advantageous to fix >dd ddfe. Otherwise, I'd better 
>> go straight for the MPFR libraries.
> 
> There's a huge speed advantage for double double precision arithmetic 
> over multi-precision when 106 bit significand and the exponent range of 
> ordinary double precision suffices. IMO, it's worth having a usable 
> Forth library for double double arithmetic.

I meant: use MPFR instead of vpa() to debug and check double-double.

For circuit simulation, control, and system identification, it's 
possible to avoid >DD (although I'm curious what went wrong there).

-marcel

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#135654

From	Krishna Myneni <krishna.myneni@ccreweb.org>
Date	2026-09-10 16:51 -0500
Message-ID	<117v8pg$2cc4e$1@dont-email.me>
In reply to	#135653

On 9/10/26 15:10, marcel hendrix wrote:
> On 9/10/2026 8:35 PM, Krishna Myneni wrote:
>>
>>> If I get reports  that >dd ddfe. processes all of these fine on other 
>>> Forths it may be advantageous to fix >dd ddfe. Otherwise, I'd better 
>>> go straight for the MPFR libraries.
>>
>> There's a huge speed advantage for double double precision arithmetic 
>> over multi-precision when 106 bit significand and the exponent range 
>> of ordinary double precision suffices. IMO, it's worth having a usable 
>> Forth library for double double arithmetic.
> 
> I meant: use MPFR instead of vpa() to debug and check double-double.
> 
> For circuit simulation, control, and system identification, it's 
> possible to avoid >DD (although I'm curious what went wrong there).
> 

Ah. I've used the double double code once or twice without using >DD at 
all, but it's certainly needed for general purpose use.

--
Krishna

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#135656

From	dxf <dxforth@gmail.com>
Date	2026-09-11 12:16 +1000
Message-ID	<6aa3648f$1@news.ausics.net>
In reply to	#135651

On 11/09/2026 3:33 am, marcel hendrix wrote:
> ... 
> If I get reports  that >dd ddfe. processes all of these fine on other Forths it may be advantageous to fix >dd ddfe. Otherwise, I'd better go straight for the MPFR libraries.

Thanks for the test.

  dd# 9999999999999999999999999999999999999999999999999999d0   ddfs. 1.0000000000000000000000000000000E52
  dd# 8999999999999999999999999999999999999999999999999999d0   ddfs. 9.0000000000000000000000000000000E51
  dd# .9999999999999999999999999999999999999999999999999999d0  ddfs. 1.0000000000000000000000000000000E0
  dd# 0.99999999999999999999d44                                ddfs. 9.9999999999999999999000000000002E43
  dd# 0.99999999999999999999d34                                ddfs. 9.9999999999999999999000000000000E33
  dd# 0.99999999999999999999d30                                ddfs. 9.9999999999999999999000000000000E29
  dd# 0.99999999999999999999d28                                ddfs. 9.9999999999999999999000000000000E27
  dd# 0.9999999999999999999999999999999999999999999999999999d0 ddfs. 1.0000000000000000000000000000000E0
  dd# 1.9999999999999999999999999999999999999999999999999999d0 ddfs. 2.0000000000000000000000000000000E0

  dd# 0.00000000000000000000001d ddfs. 1.0000000000000000000000000000000E-23
  dd# 0.000000000000000000001d   ddfs. 1.0000000000000000000000000000000E-21

  dd# 0.0000000000000000001d     ddfs. 1.0000000000000000000000000000000E-19
  dd# 0.00000000000000001d       ddfs. 1.0000000000000000000000000000000E-17
  dd# 0.000000000000001d         ddfs. 1.0000000000000000000000000000000E-15
  dd# 0.0000000000000001d        ddfs. 1.0000000000000000000000000000000E-16
  dd# 1.000000000000000d-16      ddfs. 1.0000000000000000000000000000000E-16
  dd# 1.000000000000000d-15      ddfs. 1.0000000000000000000000000000000E-15
  dd# 1.000000000000000d-5       ddfs. 1.0000000000000000000000000000000E-5
  dd# 1.000000000000000d-1       ddfs. 1.0000000000000000000000000000000E-1

  dd# 1e-30                      ddfs. 1.0000000000000000000000000000000E-30
  dd# 1.0e-30                    ddfs. 1.0000000000000000000000000000000E-30

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#135657

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-11 12:05 +0200
Message-ID	<1180jpe$16qki$1@dont-email.me>
In reply to	#135656

On 9/11/2026 4:16 AM, dxf wrote:
[..]

Near perfect.
Quite a bit more useful than my results.

-marcel

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#135674

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-12 00:27 +0200
Message-ID	<1181v83$17dme$1@dont-email.me>
In reply to	#135657

On 9/11/2026 12:05 PM, marcel hendrix wrote:
> On 9/11/2026 4:16 AM, dxf wrote:
> [..]
> 
> Near perfect.
> Quite a bit more useful than my results.
I have dropped JVN's parser and switched to yours.
Indeed, a lot simpler and shorter, and bug free.
None of the previously mentioned problems and no new anomalies.

FORTH> TEST
Addition: 1/3 + 1/6
       5.00000000000000e-001       -1.54074395550979e-033 <- should be this
       5.0000000000000000000e-0001 -1.5407439555097889288e-0033

Subtraction: 1/3 - 1/6
       1.66666666666667e-001        9.25185853854297e-018 <- should be this
       1.6666666666666664964e-0001  9.2518585385429708806e-0018

Multiplication: 6 * 1/6
       1.00000000000000e+000        0.00000000000000e+000 <- should be this
       1.0000000000000000000e+0000  0.0000000000000000000e+0000
6 * 1/3
       2.00000000000000e+000        0.00000000000000e+000 <- should be this
       2.0000000000000000000e+0000  0.0000000000000000000e+0000

Division: [1/3] / [1/6]
       2.00000000000000e+000        0.00000000000000e+000 <- should be this
       2.0000000000000000000e+0000  0.0000000000000000000e+0000

[1/6] / [1/3]
       5.00000000000000e-001        0.00000000000000e+000 <- should be this
       5.0000000000000000000e-0001  0.0000000000000000000e+0000
Square root: sqrt[1/324]
       5.55555555555556e-002        3.08395284618099e-018 <- should be this
       5.5555555555555553286e-0002  3.0839528461809899528e-0018 <- 
sqrt[1/324] = 1/18
       ... multiplied by 18
       1.00000000000000e+000        0.00000000000000e+000 <- should be this
       1.0000000000000000000e+0000  0.0000000000000000000e+0000

FORTH> .TEST+
-9              1.666666666666666666666666666666e-10
-8              1.666666666666666666666666666666e-9
-7              1.666666666666666666666666666666e-8
-6              1.666666666666666666666666666666e-7
-5              1.666666666666666666666666666666e-6
-4              1.666666666666666666666666666666e-5
-3              1.666666666666666666666666666666e-4
-2              1.666666666666666666666666666666e-3
-1              1.666666666666666666666666666666e-2
0               1.666666666666666666666666666666e-1
1               1.666666666666666666666666666666e0
2               1.666666666666666666666666666666e1
3               1.666666666666666666666666666666e2
4               1.666666666666666666666666666666e3
5               1.666666666666666666666666666666e4
6               1.666666666666666666666666666666e5
7               1.666666666666666666666666666666e6
8               1.666666666666666666666666666666e7
9               1.666666666666666666666666666666e8
3.141592653589793238462643383279e0
-1.111122222333334444455555666659e-44 ( 
-1.11112222233333444445555566666e-044 )
1.111122222333334444455555666659e46 ( 
1.11112222233333444445555566666e+046 )
1.111122222333334444455555666659e1 (  1.11112222233333444445555566666e+001 )
1.111122222333000000000000000000e6 (  1.11112222233300000000000000000e+006 )

FORTH> PRINT-TEST
1.000000000000000000000000000000e-34
1.000000000000000000000000000000e-33
1.000000000000000000000000000000e-32
1.000000000000000000000000000000e-31
1.000000000000000000000000000000e-30
1.000000000000000000000000000000e-29
1.000000000000000000000000000000e-28
1.000000000000000000000000000000e-27
1.000000000000000000000000000000e-26
1.000000000000000000000000000000e-25
1.000000000000000000000000000000e-24
1.000000000000000000000000000000e-23
1.000000000000000000000000000000e-22
1.000000000000000000000000000000e-21
1.000000000000000000000000000000e-20
1.000000000000000000000000000000e-19
1.000000000000000000000000000000e-18
1.000000000000000000000000000000e-17
1.000000000000000000000000000000e-16
1.000000000000000000000000000000e-15
1.000000000000000000000000000000e-14
1.000000000000000000000000000000e-13
1.000000000000000000000000000000e-12
1.000000000000000000000000000000e-11
1.000000000000000000000000000000e-10
1.000000000000000000000000000000e-9
1.000000000000000000000000000000e-8
1.000000000000000000000000000000e-7
1.000000000000000000000000000000e-6
1.000000000000000000000000000000e-5
1.000000000000000000000000000000e-4
1.000000000000000000000000000000e-3
1.000000000000000000000000000000e-2
1.000000000000000000000000000000e-1
1.000000000000000000000000000000e0
1.000000000000000000000000000000e1
1.000000000000000000000000000000e2
1.000000000000000000000000000000e3
1.000000000000000000000000000000e4
1.000000000000000000000000000000e5
1.000000000000000000000000000000e6
1.000000000000000000000000000000e7
1.000000000000000000000000000000e8
1.000000000000000000000000000000e9
1.000000000000000000000000000000e10
1.000000000000000000000000000000e11
1.000000000000000000000000000000e12
1.000000000000000000000000000000e13
1.000000000000000000000000000000e14
1.000000000000000000000000000000e15
1.000000000000000000000000000000e16
1.000000000000000000000000000000e17
1.000000000000000000000000000000e18
1.000000000000000000000000000000e19
1.000000000000000000000000000000e20
1.000000000000000000000000000000e21
1.000000000000000000000000000000e22
1.000000000000000000000000000000e23
1.000000000000000000000000000000e24
1.000000000000000000000000000000e25
1.000000000000000000000000000000e26
1.000000000000000000000000000000e27
1.000000000000000000000000000000e28
1.000000000000000000000000000000e29
1.000000000000000000000000000000e30
1.000000000000000000000000000000e31
1.000000000000000000000000000000e32
1.000000000000000000000000000000e33

FORTH> TESTS
ddexp   max delta =  9.9471290646179302422e-0015
ddln    max delta =  1.1100635206879409926e-0016
ddlog   max delta =  1.1092437240280354566e-0016
ddsin   max delta =  5.5584892248111063040e-0017
ddcos   max delta =  5.5583702957907087366e-0017
ddtan   max delta =  3.1168367029577738248e-0014
ddasin  max delta =  1.8513496126496535048e-0016
ddacos  max delta =  3.5092045508040913926e-0016
ddatan  max delta =  1.1107850143462055686e-0016
ddsinh  max delta =  5.2214958028216371202e-0016
ddcosh  max delta =  5.0802472104219330562e-0016
ddtanh  max delta =  3.4287817519898081282e-0016
ddasinh max delta =  1.0464329155476988164e-0012
ddacosh max delta =  7.2614989467132989444e-0013
ddatanh max delta =  6.2797216632193505288e-0013

FORTH> exactmulbench
0.131 seconds elapsed.

FORTH> 1e-30 PTEST
Found 0 errors. ok


I can now test D.Bailey's library. The functions are indeed
accurate to about 30 decimals.

FORTH> CR S" ddexp" S" exp" 1e-16 TESTFUNC

ddexp( 1.000000000000000000000000000000e-30 ) has error 
-1.348833849820495919788345147690e-40
ddexp( 1.000000000000000000000000000000e-2 ) has error 
8.600338075353514991189339041209e-31
ddexp( 2.000000000000000000000000000000e-2 ) has error 
1.514353036216258607670262638799e-31
ddexp( 2.999999999999999826527652402320e-2 ) has error 
2.998974504981413075682514105269e-31
ddexp( 4.000000000000000000000000000000e-2 ) has error 
-1.452559168452108803416741833219e-31
ddexp( 5.000000000000000173472347597680e-2 ) has error 
1.003157524415731921450355576670e-30
ddexp( 6.000000000000000346944695195361e-2 ) has error 
1.178084960660913285467247510960e-31
ddexp( 7.000000000000000520417042793042e-2 ) has error 
2.746851445242115045880974909720e-30
ddexp( 8.000000000000000000000000000000e-2 ) has error 
1.888500198575557846784067350310e-30
ddexp( 8.999999999999999479582957206958e-2 ) has error 
1.280659362172425127316005064650e-30  ok

FORTH> CR S" ddln" S" log" 1e-16 TESTFUNC

ddln( 1.000000000000000000000000000000e-30 ) has error 
-1.092622802649907621080041761850e-29
ddln( 1.000000000000000000000000000000e-2 ) has error 
-7.284152019694084680689251000960e-31
ddln( 2.000000000000000000000000000000e-2 ) has error 
-5.518471264794716993160814762439e-31
ddln( 2.999999999999999826527652402320e-2 ) has error 
-5.377157022109784478978614015070e-31
ddln( 4.000000000000000000000000000000e-2 ) has error 
-1.375279050986547445573717949980e-30
ddln( 5.000000000000000173472347597680e-2 ) has error 
4.586224700703673904266268872329e-31
ddln( 6.000000000000000346944695195361e-2 ) has error 
-5.278142930437839408059431590239e-31
ddln( 7.000000000000000520417042793042e-2 ) has error 
-1.228777480697171374987884452209e-31
ddln( 8.000000000000000000000000000000e-2 ) has error 
-1.198710975502350395330748776849e-30
ddln( 8.999999999999999479582957206958e-2 ) has error 
7.657667231090196888092519365119e-31  ok

FORTH> CR S" ddlog" S" log10" 1e-16 TESTFUNC

ddlog( 1.000000000000000000000000000000e-30 ) has error 0e
ddlog( 1.000000000000000000000000000000e-2 ) has error 0e
ddlog( 2.000000000000000000000000000000e-2 ) has error 
-5.069732316644259374107623408930e-31
ddlog( 2.999999999999999826527652402320e-2 ) has error 
-6.345563982593910129511184933990e-31
ddlog( 4.000000000000000000000000000000e-2 ) has error 
-1.013946463696193859453489528030e-30
ddlog( 5.000000000000000173472347597680e-2 ) has error 
-4.438044265683155715389947391819e-31
ddlog( 6.000000000000000346944695195361e-2 ) has error 
-5.708681387428622982654112706199e-31
ddlog( 7.000000000000000520417042793042e-2 ) has error 
-5.634574788991325446928567969579e-31
ddlog( 8.000000000000000000000000000000e-2 ) has error 
-5.209196953607374225988345459659e-31
ddlog( 8.999999999999999479582957206958e-2 ) has error 
3.842429167450690235182823430440e-31  ok

\ CR S" ddatan2" S" atan2" 1e-16 TESTFUNC
\ two arguments ...

FORTH> CR S" ddsin" S" sin" 1e-16 TESTFUNC

ddsin( 1.000000000000000000000000000000e-30 ) has error 
1.290964874928831515047833236409e-70
ddsin( 1.000000000000000000000000000000e-2 ) has error 
7.290389631748150273206057203279e-34
ddsin( 2.000000000000000000000000000000e-2 ) has error 
4.515171680020113802233606431339e-33
ddsin( 2.999999999999999826527652402320e-2 ) has error 
1.024305279605862250462179155179e-32
ddsin( 4.000000000000000000000000000000e-2 ) has error 
4.539256677392102516663408232700e-33
ddsin( 5.000000000000000173472347597680e-2 ) has error 
3.134065411729161552364095933970e-34
ddsin( 6.000000000000000346944695195361e-2 ) has error 
4.950193885214817859084190885630e-33
ddsin( 7.000000000000000520417042793042e-2 ) has error 
5.968689191909616265825855195940e-33
ddsin( 8.000000000000000000000000000000e-2 ) has error 
7.197947100174773392659851343960e-33
ddsin( 8.999999999999999479582957206958e-2 ) has error 
5.239029175657238047432152538220e-33  ok

FORTH> CR S" ddsin" S" cos" 1e-16 TESTFUNC

ddsin( 1.000000000000000000000000000000e-30 ) has error 
1.000000000000000000000000000000e0
ddsin( 1.000000000000000000000000000000e-2 ) has error 
9.899501670824986130977154954829e-1
ddsin( 2.000000000000000000000000000000e-2 ) has error 
9.798013399732446990462052961449e-1
ddsin( 2.999999999999999826527652402320e-2 ) has error 
9.695545335464918572896091718730e-1
ddsin( 4.000000000000000000000000000000e-2 ) has error 
9.592107724743437808620239464129e-1
ddsin( 5.000000000000000173472347597680e-2 ) has error 
9.487710911242879159487502487220e-1
ddsin( 6.000000000000000346944695195361e-2 ) has error 
9.382365334557595626773247891020e-1
ddsin( 7.000000000000000520417042793042e-2 ) has error 
9.276081529157468050889411695019e-1
ddsin( 8.000000000000000000000000000000e-2 ) has error 
9.168870123334466976708304273190e-1
ddsin( 8.999999999999999479582957206958e-2 ) has error 
9.060741838139832090524364378170e-1  ok

FORTH> CR S" ddcos" S" cos" 1e-16 TESTFUNC

ddcos( 1.000000000000000000000000000000e-30 ) has error 0e
ddcos( 1.000000000000000000000000000000e-2 ) has error 
6.673212561067486843840793607170e-33
ddcos( 2.000000000000000000000000000000e-2 ) has error 
7.526312612417050062625416940190e-32
ddcos( 2.999999999999999826527652402320e-2 ) has error 
4.991119505465397429820441385450e-32
ddcos( 4.000000000000000000000000000000e-2 ) has error 
3.466045735058796483333400738680e-32
ddcos( 5.000000000000000173472347597680e-2 ) has error 
5.711477847116620720646795216269e-32
ddcos( 6.000000000000000346944695195361e-2 ) has error 
3.490930828317319771611444452900e-33
ddcos( 7.000000000000000520417042793042e-2 ) has error 
9.840437648319452183938735868770e-32
ddcos( 8.000000000000000000000000000000e-2 ) has error 
1.138463638195948363383308790010e-32
ddcos( 8.999999999999999479582957206958e-2 ) has error 
2.273955199333038303450258665160e-32  ok

FORTH> CR S" ddtan" S" tan" 1e-16 TESTFUNC

ddtan( 1.000000000000000000000000000000e-30 ) has error 
1.290964874928831515047833236409e-70
ddtan( 1.000000000000000000000000000000e-2 ) has error 
1.356498499969104507969362088660e-34
ddtan( 2.000000000000000000000000000000e-2 ) has error 
7.499427041092531945789983216280e-33
ddtan( 2.999999999999999826527652402320e-2 ) has error 
7.915306915937973624752303890500e-33
ddtan( 4.000000000000000000000000000000e-2 ) has error 
2.284921091621521695851025139100e-33
ddtan( 5.000000000000000173472347597680e-2 ) has error 
-3.805459407084820375805004111260e-33
ddtan( 6.000000000000000346944695195361e-2 ) has error 
3.361910016461688140288158486589e-34
ddtan( 7.000000000000000520417042793042e-2 ) has error 
4.554769145413700003976460109889e-34
ddtan( 8.000000000000000000000000000000e-2 ) has error 
3.083540312232744705631474629049e-33
ddtan( 8.999999999999999479582957206958e-2 ) has error 
9.024430237840674891541669272820e-33  ok

FORTH> CR S" ddasin" S" asin" 1e-16 TESTFUNC

ddasin( 1.000000000000000000000000000000e-30 ) has error 
1.290964874928831515047833236409e-70
ddasin( 1.000000000000000000000000000000e-2 ) has error 
3.836785690854971254728706845369e-34
ddasin( 2.000000000000000000000000000000e-2 ) has error 
7.214987008818724808571807850710e-33
ddasin( 2.999999999999999826527652402320e-2 ) has error 
1.530078737960660717704968378030e-32
ddasin( 4.000000000000000000000000000000e-2 ) has error 
7.121489294333722604341271065450e-33
ddasin( 5.000000000000000173472347597680e-2 ) has error 
2.039607022291208069536436098360e-33
ddasin( 6.000000000000000346944695195361e-2 ) has error 
-1.959980667389534150441733218940e-34
ddasin( 7.000000000000000520417042793042e-2 ) has error 
3.469938050168774031426656916730e-33
ddasin( 8.000000000000000000000000000000e-2 ) has error 
7.888042573442366724857125092560e-33
ddasin( 8.999999999999999479582957206958e-2 ) has error 
9.208231726154620277253703885049e-33  ok

FORTH> CR S" ddacos" S" acos" 1e-16 TESTFUNC

ddacos( 1.000000000000000000000000000000e-30 ) has error 
7.514420985121228877154091890689e-31
ddacos( 1.000000000000000000000000000000e-2 ) has error 
7.610584200509264430482897053479e-31
ddacos( 2.000000000000000000000000000000e-2 ) has error 
9.742271114832300210533753864949e-31
ddacos( 2.999999999999999826527652402320e-2 ) has error 
6.161413112043154407336782795309e-31
ddacos( 4.000000000000000000000000000000e-2 ) has error 
8.543206092456192420392579168299e-31
ddacos( 5.000000000000000173472347597680e-2 ) has error 
4.694024916190571586141666934200e-31
ddacos( 6.000000000000000346944695195361e-2 ) has error 
5.016380966857150320965084866029e-31
ddacos( 7.000000000000000520417042793042e-2 ) has error 
8.279721607179567762790112815190e-31
ddacos( 8.000000000000000000000000000000e-2 ) has error 
1.235540558272262341440469067930e-31
ddacos( 8.999999999999999479582957206958e-2 ) has error 
5.622338669957151670971241249210e-31  ok

FORTH> CR S" ddatan" S" atan" 1e-16 TESTFUNC

ddatan( 1.000000000000000000000000000000e-30 ) has error 
1.290964874928831515047833236409e-70
ddatan( 1.000000000000000000000000000000e-2 ) has error 
5.485613684696977471531700996090e-34
ddatan( 2.000000000000000000000000000000e-2 ) has error 
6.487949232904254807669862100440e-33
ddatan( 2.999999999999999826527652402320e-2 ) has error 
1.195752602792821075907015140519e-32
ddatan( 4.000000000000000000000000000000e-2 ) has error 
5.403597016275488426646022725890e-33
ddatan( 5.000000000000000173472347597680e-2 ) has error 
-2.924144718370069112308118474640e-33
ddatan( 6.000000000000000346944695195361e-2 ) has error 
2.285558054607446306956452052530e-33
ddatan( 7.000000000000000520417042793042e-2 ) has error 
3.856519790969437242620035860489e-33
ddatan( 8.000000000000000000000000000000e-2 ) has error 
2.356915763086840590404552361310e-33
ddatan( 8.999999999999999479582957206958e-2 ) has error 
6.163294222026993156343182759780e-33  ok

FORTH> CR S" ddsinh" S" sinh" 1e-16 TESTFUNC

ddsinh( 1.000000000000000000000000000000e-30 ) has error 
1.290964874928831515047833236409e-70
ddsinh( 1.000000000000000000000000000000e-2 ) has error 
1.738017642488525580906385444570e-33
ddsinh( 2.000000000000000000000000000000e-2 ) has error 
1.284501895737655321054043087620e-33
ddsinh( 2.999999999999999826527652402320e-2 ) has error 
8.589789601391734571244827357840e-33
ddsinh( 4.000000000000000000000000000000e-2 ) has error 
4.429027506164139776058216919020e-33
ddsinh( 5.000000000000000173472347597680e-2 ) has error 
3.215602707290917444503530202479e-34
ddsinh( 6.000000000000000346944695195361e-2 ) has error 
-2.535197330307830264290663865449e-31
ddsinh( 7.000000000000000520417042793042e-2 ) has error 
1.788268195823099216597933888669e-30
ddsinh( 8.000000000000000000000000000000e-2 ) has error 
9.398450775735506187267743397249e-31
ddsinh( 8.999999999999999479582957206958e-2 ) has error 
6.182399680310202146071100103750e-31  ok

FORTH> CR S" ddcosh" S" cosh" 1e-16 TESTFUNC

ddcosh( 1.000000000000000000000000000000e-30 ) has error 0e
ddcosh( 1.000000000000000000000000000000e-2 ) has error 
4.482957896931047604239708815079e-31
ddcosh( 2.000000000000000000000000000000e-2 ) has error 
2.301508014317915376917934815289e-31
ddcosh( 2.999999999999999826527652402320e-2 ) has error 
9.613076609377395707317593443200e-31
ddcosh( 4.000000000000000000000000000000e-2 ) has error 
5.031505556728802848628203921139e-32
ddcosh( 5.000000000000000173472347597680e-2 ) has error 
6.828359640406699666560249690980e-31
ddcosh( 6.000000000000000346944695195361e-2 ) has error 
1.913282292213774664529525053199e-31
ddcosh( 7.000000000000000520417042793042e-2 ) has error 
5.485832495795734903008245973260e-31
ddcosh( 8.000000000000000000000000000000e-2 ) has error 
6.386551210018948180861637718999e-31
ddcosh( 8.999999999999999479582957206958e-2 ) has error 
8.624193943245994802142911611059e-31  ok

FORTH> CR S" ddtanh" S" tanh" 1e-16 TESTFUNC

ddtanh( 1.000000000000000000000000000000e-30 ) has error 
-8.333642060758499999999987089119e-47
ddtanh( 1.000000000000000000000000000000e-2 ) has error 
7.844975100106199584188090790880e-31
ddtanh( 2.000000000000000000000000000000e-2 ) has error 
-4.734972483045822567043754674039e-31
ddtanh( 2.999999999999999826527652402320e-2 ) has error 
2.865778710387485567904833251770e-31
ddtanh( 4.000000000000000000000000000000e-2 ) has error 
-2.002502897236812132009267986099e-31
ddtanh( 5.000000000000000173472347597680e-2 ) has error 
2.692826102390931598049100319459e-31
ddtanh( 6.000000000000000346944695195361e-2 ) has error 
-2.580485979064130394226843064729e-31
ddtanh( 7.000000000000000520417042793042e-2 ) has error 
1.772131697238414674415147230000e-30
ddtanh( 8.000000000000000000000000000000e-2 ) has error 
9.292226091414370403296759748630e-31
ddtanh( 8.999999999999999479582957206958e-2 ) has error 
6.110342827488042702178137829269e-31  ok

FORTH> CR S" ddasinh" S" asinh" 1e-16 TESTFUNC

ddasinh( 1.000000000000000000000000000000e-30 ) has error 
-8.333642060758499999999987089119e-47
ddasinh( 1.000000000000000000000000000000e-2 ) has error 
-1.204017783513088875087169292859e-33
ddasinh( 2.000000000000000000000000000000e-2 ) has error 
-1.020338821497062001860839183569e-32
ddasinh( 2.999999999999999826527652402320e-2 ) has error 
4.269470267912267380624194688089e-31
ddasinh( 4.000000000000000000000000000000e-2 ) has error 
1.973706240112667547747601759499e-31
ddasinh( 5.000000000000000173472347597680e-2 ) has error 
1.203857231291711272345953843090e-31
ddasinh( 6.000000000000000346944695195361e-2 ) has error 
-3.126948516141051007893085333899e-31
ddasinh( 7.000000000000000520417042793042e-2 ) has error 
-1.770134963051862291627229247179e-31
ddasinh( 8.000000000000000000000000000000e-2 ) has error 
2.057312346823413199351525064629e-31
ddasinh( 8.999999999999999479582957206958e-2 ) has error 
5.016247807688765416006818398420e-31  ok

\ FORTH> CR S" ddacosh" S" acosh" 1e-16 TESTFUNC
\ is complex...

FORTH> CR S" ddatanh" S" atanh" 1e-16 TESTFUNC

ddatanh( 1.000000000000000000000000000000e-30 ) has error 
-8.333642060758499999999987089119e-47
ddatanh( 1.000000000000000000000000000000e-2 ) has error 
-4.577611290134768056843627501779e-32
ddatanh( 2.000000000000000000000000000000e-2 ) has error 
6.390480763559417940367094184680e-33
ddatanh( 2.999999999999999826527652402320e-2 ) has error 
3.230097283984874648927682648819e-32
ddatanh( 4.000000000000000000000000000000e-2 ) has error 
-4.011799660821192898181963685989e-32
ddatanh( 5.000000000000000173472347597680e-2 ) has error 
5.958276002720974224428216113209e-32
ddatanh( 6.000000000000000346944695195361e-2 ) has error 
1.086191751963114892868664141139e-31
ddatanh( 7.000000000000000520417042793042e-2 ) has error 
3.095731704082193474233882143270e-32
ddatanh( 8.000000000000000000000000000000e-2 ) has error 
1.104977500424901871362041159020e-31
ddatanh( 8.999999999999999479582957206958e-2 ) has error 
-1.049074159649000666264780467730e-31  ok

-marcel

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#135678

From	Krishna Myneni <krishna.myneni@ccreweb.org>
Date	2026-09-11 20:29 -0500
Message-ID	<11829tr$3chqi$1@dont-email.me>
In reply to	#135674

On 9/11/26 5:27 PM, marcel hendrix wrote:
> On 9/11/2026 12:05 PM, marcel hendrix wrote:
>> On 9/11/2026 4:16 AM, dxf wrote:
>> [..]
>>
>> Near perfect.
>> Quite a bit more useful than my results.
> I have dropped JVN's parser and switched to yours.
> Indeed, a lot simpler and shorter, and bug free.
> None of the previously mentioned problems and no new anomalies.
> ...

Good news. I lost track of the sequence of patches dxforth made. Is 
there an update of the entire ddfloat library on pastebin?

--
Krishna

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#135679

From	dxf <dxforth@gmail.com>
Date	2026-09-12 12:02 +1000
Message-ID	<6aa4b2bf$1@news.ausics.net>
In reply to	#135678

On 12/09/2026 11:29 am, Krishna Myneni wrote:
> On 9/11/26 5:27 PM, marcel hendrix wrote:
>> On 9/11/2026 12:05 PM, marcel hendrix wrote:
>>> On 9/11/2026 4:16 AM, dxf wrote:
>>> [..]
>>>
>>> Near perfect.
>>> Quite a bit more useful than my results.
>> I have dropped JVN's parser and switched to yours.
>> Indeed, a lot simpler and shorter, and bug free.
>> None of the previously mentioned problems and no new anomalies.
>> ...
> 
> Good news. I lost track of the sequence of patches dxforth made. Is there an update of the entire ddfloat library on pastebin?

https://pastebin.com/TdcLJhXP

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#135685

From	Krishna Myneni <krishna.myneni@ccreweb.org>
Date	2026-09-12 10:24 -0500
Message-ID	<1183qs8$3s5pj$1@dont-email.me>
In reply to	#135679

On 9/11/26 9:02 PM, dxf wrote:
> On 12/09/2026 11:29 am, Krishna Myneni wrote:
>> On 9/11/26 5:27 PM, marcel hendrix wrote:
>>> On 9/11/2026 12:05 PM, marcel hendrix wrote:
>>>> On 9/11/2026 4:16 AM, dxf wrote:
>>>> [..]
>>>>
>>>> Near perfect.
>>>> Quite a bit more useful than my results.
>>> I have dropped JVN's parser and switched to yours.
>>> Indeed, a lot simpler and shorter, and bug free.
>>> None of the previously mentioned problems and no new anomalies.
>>> ...
>>
>> Good news. I lost track of the sequence of patches dxforth made. Is there an update of the entire ddfloat library on pastebin?
> 
> https://pastebin.com/TdcLJhXP
> 
> 
Got it. Thank you.

--
KM

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#135680

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-12 10:45 +0200
Message-ID	<11833g2$1818h$1@dont-email.me>
In reply to	#135678

On 9/12/2026 3:29 AM, Krishna Myneni wrote:
> On 9/11/26 5:27 PM, marcel hendrix wrote:
>> On 9/11/2026 12:05 PM, marcel hendrix wrote:
>>> On 9/11/2026 4:16 AM, dxf wrote:
>>> [..]
>>>
>>> Near perfect.
>>> Quite a bit more useful than my results.
>> I have dropped JVN's parser and switched to yours.
>> Indeed, a lot simpler and shorter, and bug free.
>> None of the previously mentioned problems and no new anomalies.
>> ...
> 
> Good news. I lost track of the sequence of patches dxforth made. Is 
> there an update of the entire ddfloat library on pastebin?

I *only* used the >DD definition found in 
http://dxforth.webhop.org/finput.html . It has a rough spot: it does not 
catch invalid floats like JVN's did. S" -NAN +NAN" >DD gave an infinite 
loop in my tests. Maybe a "safe" >DDS could be added.-marcel

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#135683

From	dxf <dxforth@gmail.com>
Date	2026-09-12 19:51 +1000
Message-ID	<6aa520b2$1@news.ausics.net>
In reply to	#135680

On 12/09/2026 6:45 pm, marcel hendrix wrote:
> On 9/12/2026 3:29 AM, Krishna Myneni wrote:
>> On 9/11/26 5:27 PM, marcel hendrix wrote:
>>> On 9/11/2026 12:05 PM, marcel hendrix wrote:
>>>> On 9/11/2026 4:16 AM, dxf wrote:
>>>> [..]
>>>>
>>>> Near perfect.
>>>> Quite a bit more useful than my results.
>>> I have dropped JVN's parser and switched to yours.
>>> Indeed, a lot simpler and shorter, and bug free.
>>> None of the previously mentioned problems and no new anomalies.
>>> ...
>>
>> Good news. I lost track of the sequence of patches dxforth made. Is there an update of the entire ddfloat library on pastebin?
> 
> I *only* used the >DD definition found in http://dxforth.webhop.org/finput.html . It has a rough spot: it does not catch invalid floats like JVN's did. S" -NAN +NAN" >DD gave an infinite loop in my tests. Maybe a "safe" >DDS could be added.-marcel

Printing an invalid float (junk input) will hang too and is perhaps the
greater issue.  Do we have a rigorous definition for what is 'invalid'
when it comes to these synthesized doubles?  Because if not, there can't
be a solution.

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#135684

From	dxf <dxforth@gmail.com>
Date	2026-09-12 22:47 +1000
Message-ID	<6aa549e4$1@news.ausics.net>
In reply to	#135680

On 12/09/2026 6:45 pm, marcel hendrix wrote:
> ...
> I *only* used the >DD definition found in http://dxforth.webhop.org/finput.html . It has a rough spot: it does not catch invalid floats like JVN's did. S" -NAN +NAN" >DD gave an infinite loop in my tests. Maybe a "safe" >DDS could be added.-marcel

Testing my DDFLOAT.F on Win32Forth:

  S" +NAN -NAN" >DD . 0  ok  \ flag=false

  DD# +NAN -NAN 
      ^^^^
  Error(-2): +NAN bad float

OTOH the following *will* get through:

  DD# 1e400  ok

  f.s {2} +NAN +NAN  ok

The original >DD accepts 1e400 gives the same NAN-NAN result.

The latter result when presented to DDFS. will cause an infinite loop due to
the NORMALIZE word.  This problem existed in the original DDFS.  How one
fixes it depends on what is available.  If your forth includes a word that
tests TOS for a NAN/INF etc. then you're in luck.  Let's call that word:

  NAN? ( r -- flag )

Fixing DDFS. (or what have you) is simply a matter of testing for NAN/INF
before passing to NORMALIZE (which BTW can't handle 0.0E either).  In your
case the fix would be something like this:

  FOVER F0= IF  F2DROP S" 0e" EXIT  ENDIF
  F2DUP NAN? >R  NAN?  R> OR IF  F2DROP S" NAN/INF" EXIT  ENDIF

HTH

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#135687

From	dxf <dxforth@gmail.com>
Date	2026-09-13 03:14 +1000
Message-ID	<6aa58871$1@news.ausics.net>
In reply to	#135684

In addition to NAN/INFs causing DDFS. to enter an infinite loop, numbers that
are too small/large can also do so.  Below is a patch that attempts to fix
these issues.  The patch can be applied to the DDFLOAT version here:

https://pastebin.com/TdcLJhXP

Implementation of the NAN? function I leave to users as there several options -
none of which are easy, portable, and foolproof.  But I'm always willing to be
surprised.

---8<--- 

\ Patch for DDFLOAT.F  2026-09-13
\
\ Fix infinite loop displaying floats that are:
\ - too small/large
\ - NAN/INF **
\
\ ** requires a function that can detect NAN/INF e.g.
\  NAN? ( F: r -- ) ( -- flag )
\

: fzero ( x xx -- )  DDDROP  S" 0.E0" HOLDS  0 ;

: range? ( r -- r 0 | -1 )  \ handle problem numbers
  FOVER F0= IF  fzero  EXIT  THEN
\  FDUP NAN? >R  FOVER NAN?  R> OR IF
\    DDDROP  S" NAN/INF" HOLDS  0  EXIT
\  THEN
  getpower  dup -298 < IF  drop  fzero  EXIT  THEN
  299 > IF  DDDROP  S" INF" HOLDS  0  EXIT  THEN
  -1
;

: (DDFS.) ( dd -- c-addr u )  \ string double-double in E-format
  <#  range? IF
    getsign >R
    getpower        ( x xx n)
    normalize >R    ( y yy)
    peeldigits  copydigits
    dig$ maxdig ( a u)  0digit-fix  R> +  \ adjust exp
    ( p) DUP ABS 0 #S 2DROP  SIGN  \ exponent
    [char] E HOLD  ( a u)
    1-  OVER 1+ SWAP  HOLDS  [char] .  HOLD  C@ HOLD
    R> ( s) IF  [char] - HOLD  THEN
  THEN  0 0 #>
;

\\

cr 
 ok
dd# 1e-296  ddfs. 1.0000000000000000000000000000000E-296  ok
dd# 1e-297  ddfs. 1.0000000000000000000000000000000E-297  ok
dd# 1e-298  ddfs. 1.0000000000000000000000000000000E-298  ok
dd# 1e-299  ddfs. 0.E0  ok
dd# 1e-300  ddfs. 0.E0  ok
dd# 1e-301  ddfs. 0.E0  ok
dd# 1e-302  ddfs. 0.E0  ok
dd# 1e-303  ddfs. 0.E0  ok
cr 
 ok
dd# 1e+296  ddfs. 1.0000000000000000000000000000001E296  ok
dd# 1e+297  ddfs. 1.0000000000000000000000000000001E297  ok
dd# 1e+298  ddfs. 1.0000000000000000000000000000001E298  ok
dd# 1e+299  ddfs. 1.0000000000000000000000000000001E299  ok
dd# 1e+300  ddfs. INF  ok
dd# 1e+301  ddfs. INF  ok
\ dd# 1e+302  ddfs. NAN/INF  ok
\ dd# 1e+303  ddfs. NAN/INF  ok
\ dd# 1e+304  ddfs. NAN/INF  ok
\ dd# 1e+305  ddfs. NAN/INF  ok
    
---8<---

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#135688

From	Krishna Myneni <krishna.myneni@ccreweb.org>
Date	2026-09-12 13:02 -0500
Message-ID	<118443l$3vqjn$1@dont-email.me>
In reply to	#135687

On 9/12/26 12:14 PM, dxf wrote:
> In addition to NAN/INFs causing DDFS. to enter an infinite loop, numbers that
> are too small/large can also do so.  Below is a patch that attempts to fix
> these issues.  The patch can be applied to the DDFLOAT version here:
> 
> https://pastebin.com/TdcLJhXP
> 
> Implementation of the NAN? function I leave to users as there several options -
> none of which are easy, portable, and foolproof.  But I'm always willing to be
> surprised.
> 
...


See https://github.com/mynenik/kForth-32/blob/master/forth-src/ieee-754.4th

The IEEE proposal, in progress, calls this word FNAN?

The file linked above provides standard definitions for FNAN? as well as 
tests for plus and minus infinities and normal and subnormal numbers. 
There are tests for these words as well.

--
KM

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#135690

From	dxf <dxforth@gmail.com>
Date	2026-09-13 15:44 +1000
Message-ID	<6aa6384b$1@news.ausics.net>
In reply to	#135688

On 13/09/2026 4:02 am, Krishna Myneni wrote:
> On 9/12/26 12:14 PM, dxf wrote:
>> In addition to NAN/INFs causing DDFS. to enter an infinite loop, numbers that
>> are too small/large can also do so.  Below is a patch that attempts to fix
>> these issues.  The patch can be applied to the DDFLOAT version here:
>>
>> https://pastebin.com/TdcLJhXP
>>
>> Implementation of the NAN? function I leave to users as there several options -
>> none of which are easy, portable, and foolproof.  But I'm always willing to be
>> surprised.
>>
> ...
> 
> 
> See https://github.com/mynenik/kForth-32/blob/master/forth-src/ieee-754.4th
> 
> The IEEE proposal, in progress, calls this word FNAN?
> 
> The file linked above provides standard definitions for FNAN? as well as tests for plus and minus infinities and normal and subnormal numbers. There are tests for these words as well.

Thanks for that.  NAN? here however is intended to encompass everything that's
not a zero, normal, or subnormal number.  I realized the name could be confusing
but until now it was hidden in my implementations.

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#135691

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-13 09:00 +0200
Message-ID	<1185hme$195e1$1@dont-email.me>
In reply to	#135687

On 9/12/2026 7:14 PM, dxf wrote:
> dd# 1e-296  ddfs. 1.0000000000000000000000000000000E-296  ok
> dd# 1e-297  ddfs. 1.0000000000000000000000000000000E-297  ok
[..]
> dd# 1e+300  ddfs. INF  ok
> dd# 1e+301  ddfs. INF  ok
> \ dd# 1e+302  ddfs. NAN/INF  ok
> \ dd# 1e+303  ddfs. NAN/INF  ok
> \ dd# 1e+304  ddfs. NAN/INF  ok
> \ dd# 1e+305  ddfs. NAN/INF  ok

My interest is only in >DD . I now allow the exponent range [-294,+304] 
(this gives a reasonable mantissa size, e.g.
FORTH> s" 1000.0e+304  " >dd ddfe.  1.000000000000000000000000000000e307

Nan/Inf are caught because their dp and/or exponent indicator are 
missing and there are no digits present:
FORTH> s" nan  " >dd ddfe.
 >DD :: dp must be `.`
FORTH> s" -inf " >dd ddfe.
 >DD :: dp must be `.`
FORTH> s" 1e   " >dd ddfe.  1.000000000000000000000000000000e0
FORTH> s" 1.1  " >dd ddfe.  1.100000000000000000000000000000e0  ok
FORTH> s" 1.1e " >dd ddfe.  1.100000000000000000000000000000e0  ok
FORTH> s" 1.1e1" >dd ddfe.  1.100000000000000000000000000000e1  ok
FORTH> 53-bits! s" 1..1e++1" >dd ddfe.
Error -2
 >DD :: not a valid exponent sign ?

I just noticed these problem:
FORTH> s" 1"       >dd ddfe.  1.000000000000000000000000000000e303  ok
FORTH> s" 1.1e++1" >dd ddfe.  1.100000000000000000000000000000e0  ok
FORTH> s" 1.1e+-1" >dd ddfe.  1.100000000000000000000000000000e0  ok
FORTH> s" 1.1e-+1" >dd ddfe.  1.100000000000000000000000000000e0  ok

The '.' can be replaced by ',' and the 'e' by 'd' as settable options.

-marcel

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#135692

From	dxf <dxforth@gmail.com>
Date	2026-09-13 20:33 +1000
Message-ID	<6aa67bfa$1@news.ausics.net>
In reply to	#135691

On 13/09/2026 5:00 pm, marcel hendrix wrote:
> On 9/12/2026 7:14 PM, dxf wrote:
>> dd# 1e-296  ddfs. 1.0000000000000000000000000000000E-296  ok
>> dd# 1e-297  ddfs. 1.0000000000000000000000000000000E-297  ok
> [..]
>> dd# 1e+300  ddfs. INF  ok
>> dd# 1e+301  ddfs. INF  ok
>> \ dd# 1e+302  ddfs. NAN/INF  ok
>> \ dd# 1e+303  ddfs. NAN/INF  ok
>> \ dd# 1e+304  ddfs. NAN/INF  ok
>> \ dd# 1e+305  ddfs. NAN/INF  ok
> 
> My interest is only in >DD . I now allow the exponent range [-294,+304] (this gives a reasonable mantissa size, e.g.
> FORTH> s" 1000.0e+304  " >dd ddfe.  1.000000000000000000000000000000e307
>
> Nan/Inf are caught because their dp and/or exponent indicator are missing and there are no digits present:
> FORTH> s" nan  " >dd ddfe.
>>DD :: dp must be `.`
> FORTH> s" -inf " >dd ddfe.
>>DD :: dp must be `.`
> FORTH> s" 1e   " >dd ddfe.  1.000000000000000000000000000000e0
> FORTH> s" 1.1  " >dd ddfe.  1.100000000000000000000000000000e0  ok
> FORTH> s" 1.1e " >dd ddfe.  1.100000000000000000000000000000e0  ok
> FORTH> s" 1.1e1" >dd ddfe.  1.100000000000000000000000000000e1  ok
> FORTH> 53-bits! s" 1..1e++1" >dd ddfe.
> Error -2
>>DD :: not a valid exponent sign ?
> 
> I just noticed these problem:
> FORTH> s" 1"       >dd ddfe.  1.000000000000000000000000000000e303  ok
> FORTH> s" 1.1e++1" >dd ddfe.  1.100000000000000000000000000000e0  ok
> FORTH> s" 1.1e+-1" >dd ddfe.  1.100000000000000000000000000000e0  ok
> FORTH> s" 1.1e-+1" >dd ddfe.  1.100000000000000000000000000000e0  ok
> 
> The '.' can be replaced by ',' and the 'e' by 'd' as settable options.

I assume you're not using my >DD any more.  The latter is creating unintended
consequences for DDFS. in the form of patches to avoid infinite loops.  Either
way it's looking messy.

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#135694

From	dxf <dxforth@gmail.com>
Date	2026-09-14 13:28 +1000
Message-ID	<6aa769c9$1@news.ausics.net>
In reply to	#135691

On 13/09/2026 5:00 pm, marcel hendrix wrote:
> ... 
> My interest is only in >DD . I now allow the exponent range [-294,+304] (this gives a reasonable mantissa size, e.g.
> FORTH> s" 1000.0e+304  " >dd ddfe.  1.000000000000000000000000000000e307

How did you get that?  NORMALIZE (even if it doesn't hang) will cause
1e307 to be converted to NAN NAN and extracting digits from that will
result in a string of '0's.

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#135695

From	marcel hendrix <mhx@iae.nl>
Date	2026-09-14 10:09 +0200
Message-ID	<1188a3t$2v3j3$1@dont-email.me>
In reply to	#135694

On 9/14/2026 5:28 AM, dxf wrote:
> On 13/09/2026 5:00 pm, marcel hendrix wrote:
>> ...
>> My interest is only in >DD . I now allow the exponent range [-294,+304] (this gives a reasonable mantissa size, e.g.
>> FORTH> s" 1000.0e+304  " >dd ddfe.  1.000000000000000000000000000000e307
> 
> How did you get that?  NORMALIZE (even if it doesn't hang) will cause
> 1e307 to be converted to NAN NAN and extracting digits from that will
> result in a string of '0's.

Slightly dirty...: normalize ( F: x xx -- |y + yy| ) ( n -- n' ) 
ddabs                   ( F: -- |x + xx| )
         DUP  dd=10 dd^n  dd/    ( F: -- [|x+xx|]/10^n ) ( -- n )
         BEGIN   FOVER 10e F>=	\ make sure it's between 1 and 10
         WHILE   dd=10 dd/  1+
         REPEAT
         BEGIN   FOVER 1e F<	\ make sure it's between 1 and 10
         WHILE   dd=10 dd*  1-
         REPEAT ;

-marcel

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ddfloat library: the behavior of >dd

Contents

#135651 — ddfloat library: the behavior of >dd

#135652

#135653

#135654

#135656

#135657

#135674

#135678

#135679

#135685

#135680

#135683

#135684

#135687

#135688

#135690

#135691

#135692

#135694

#135695