1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S Y S T E M . P O W T E N _ T A B L E -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This package provides a powers of ten table used for real conversions 33 34package System.Powten_Table is 35 pragma Pure; 36 37 Maxpow : constant := 22; 38 -- The number of entries in this table is chosen to include powers of ten 39 -- that are exactly representable with long_long_float. Assuming that on 40 -- all targets we have 53 bits of mantissa for the type, the upper bound is 41 -- given by 53/(log 5). If the scaling factor for a string is greater than 42 -- Maxpow, it can be obtained by several multiplications, which is less 43 -- efficient than with a bigger table, but avoids anomalies at end points. 44 45 Powten : constant array (0 .. Maxpow) of Long_Long_Float := 46 (00 => 1.0E+00, 47 01 => 1.0E+01, 48 02 => 1.0E+02, 49 03 => 1.0E+03, 50 04 => 1.0E+04, 51 05 => 1.0E+05, 52 06 => 1.0E+06, 53 07 => 1.0E+07, 54 08 => 1.0E+08, 55 09 => 1.0E+09, 56 10 => 1.0E+10, 57 11 => 1.0E+11, 58 12 => 1.0E+12, 59 13 => 1.0E+13, 60 14 => 1.0E+14, 61 15 => 1.0E+15, 62 16 => 1.0E+16, 63 17 => 1.0E+17, 64 18 => 1.0E+18, 65 19 => 1.0E+19, 66 20 => 1.0E+20, 67 21 => 1.0E+21, 68 22 => 1.0E+22); 69 70end System.Powten_Table; 71