| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . P O W T E N _ F L T -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2020-2023, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package provides tables of powers used for real conversions |
| |
| package System.Powten_Flt is |
| pragma Pure; |
| |
| Maxpow_Exact : constant := 10; |
| -- Largest power of five exactly representable with Float. It is equal to |
| -- floor (M * log 2 / log 5), when M is the size of the mantissa (24). |
| -- It also works for any number of the form 5*(2**N) and in particular 10. |
| |
| Maxpow : constant := Maxpow_Exact * 2; |
| -- Largest power of five exactly representable with double Float |
| |
| Powfive : constant array (0 .. Maxpow, 1 .. 2) of Float := |
| [00 => [5.0**00, 0.0], |
| 01 => [5.0**01, 0.0], |
| 02 => [5.0**02, 0.0], |
| 03 => [5.0**03, 0.0], |
| 04 => [5.0**04, 0.0], |
| 05 => [5.0**05, 0.0], |
| 06 => [5.0**06, 0.0], |
| 07 => [5.0**07, 0.0], |
| 08 => [5.0**08, 0.0], |
| 09 => [5.0**09, 0.0], |
| 10 => [5.0**10, 0.0], |
| 11 => [5.0**11, 5.0**11 - Float'Machine (5.0**11)], |
| 12 => [5.0**12, 5.0**12 - Float'Machine (5.0**12)], |
| 13 => [5.0**13, 5.0**13 - Float'Machine (5.0**13)], |
| 14 => [5.0**14, 5.0**14 - Float'Machine (5.0**14)], |
| 15 => [5.0**15, 5.0**15 - Float'Machine (5.0**15)], |
| 16 => [5.0**16, 5.0**16 - Float'Machine (5.0**16)], |
| 17 => [5.0**17, 5.0**17 - Float'Machine (5.0**17)], |
| 18 => [5.0**18, 5.0**18 - Float'Machine (5.0**18)], |
| 19 => [5.0**19, 5.0**19 - Float'Machine (5.0**19)], |
| 20 => [5.0**20, 5.0**20 - Float'Machine (5.0**20)]]; |
| |
| Powten : constant array (0 .. Maxpow, 1 .. 2) of Float := |
| [00 => [1.0E+00, 0.0], |
| 01 => [1.0E+01, 0.0], |
| 02 => [1.0E+02, 0.0], |
| 03 => [1.0E+03, 0.0], |
| 04 => [1.0E+04, 0.0], |
| 05 => [1.0E+05, 0.0], |
| 06 => [1.0E+06, 0.0], |
| 07 => [1.0E+07, 0.0], |
| 08 => [1.0E+08, 0.0], |
| 09 => [1.0E+09, 0.0], |
| 10 => [1.0E+10, 0.0], |
| 11 => [1.0E+11, 1.0E+11 - Float'Machine (1.0E+11)], |
| 12 => [1.0E+12, 1.0E+12 - Float'Machine (1.0E+12)], |
| 13 => [1.0E+13, 1.0E+13 - Float'Machine (1.0E+13)], |
| 14 => [1.0E+14, 1.0E+14 - Float'Machine (1.0E+14)], |
| 15 => [1.0E+15, 1.0E+15 - Float'Machine (1.0E+15)], |
| 16 => [1.0E+16, 1.0E+16 - Float'Machine (1.0E+16)], |
| 17 => [1.0E+17, 1.0E+17 - Float'Machine (1.0E+17)], |
| 18 => [1.0E+18, 1.0E+18 - Float'Machine (1.0E+18)], |
| 19 => [1.0E+19, 1.0E+19 - Float'Machine (1.0E+19)], |
| 20 => [1.0E+20, 1.0E+20 - Float'Machine (1.0E+20)]]; |
| |
| end System.Powten_Flt; |
