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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . P O W T E N _ L L F --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2020, 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_LLF 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 2 / log 5. If the scaling factor 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_LLF;
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