| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . P O W T E N _ T A B L E -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2009 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 a powers of ten table used for real conversions |
| |
| package System.Powten_Table is |
| pragma Pure; |
| |
| Maxpow : constant := 22; |
| -- The number of entries in this table is chosen to include powers of ten |
| -- that are exactly representable with long_long_float. Assuming that on |
| -- all targets we have 53 bits of mantissa for the type, the upper bound is |
| -- given by 53/(log 5). If the scaling factor for a string is greater than |
| -- Maxpow, it can be obtained by several multiplications, which is less |
| -- efficient than with a bigger table, but avoids anomalies at end points. |
| |
| Powten : constant array (0 .. Maxpow) of Long_Long_Float := |
| (00 => 1.0E+00, |
| 01 => 1.0E+01, |
| 02 => 1.0E+02, |
| 03 => 1.0E+03, |
| 04 => 1.0E+04, |
| 05 => 1.0E+05, |
| 06 => 1.0E+06, |
| 07 => 1.0E+07, |
| 08 => 1.0E+08, |
| 09 => 1.0E+09, |
| 10 => 1.0E+10, |
| 11 => 1.0E+11, |
| 12 => 1.0E+12, |
| 13 => 1.0E+13, |
| 14 => 1.0E+14, |
| 15 => 1.0E+15, |
| 16 => 1.0E+16, |
| 17 => 1.0E+17, |
| 18 => 1.0E+18, |
| 19 => 1.0E+19, |
| 20 => 1.0E+20, |
| 21 => 1.0E+21, |
| 22 => 1.0E+22); |
| |
| end System.Powten_Table; |
