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) 1992-1999 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 2, 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. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING. If not, write -- 19-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- As a special exception, if other files instantiate generics from this -- 23-- unit, or you link this unit with other files to produce an executable, -- 24-- this unit does not by itself cause the resulting executable to be -- 25-- covered by the GNU General Public License. This exception does not -- 26-- however invalidate any other reasons why the executable file might be -- 27-- covered by the GNU Public License. -- 28-- -- 29-- GNAT was originally developed by the GNAT team at New York University. -- 30-- Extensive contributions were provided by Ada Core Technologies Inc. -- 31-- -- 32------------------------------------------------------------------------------ 33 34-- This package provides a powers of ten table used for real conversions 35 36package System.Powten_Table is 37pragma Pure (Powten_Table); 38 39 Maxpow : constant := 22; 40 -- The number of entries in this table is chosen to include powers of ten 41 -- that are exactly representable with long_long_float. Assuming that on 42 -- all targets we have 53 bits of mantissa for the type, the upper bound is 43 -- given by 53/(log 5). If the scaling factor for a string is greater than 44 -- Maxpow, it can be obtained by several multiplications, which is less 45 -- efficient than with a bigger table, but avoids anomalies at end points. 46 47 Powten : constant array (0 .. Maxpow) of Long_Long_Float := 48 (00 => 1.0E+00, 49 01 => 1.0E+01, 50 02 => 1.0E+02, 51 03 => 1.0E+03, 52 04 => 1.0E+04, 53 05 => 1.0E+05, 54 06 => 1.0E+06, 55 07 => 1.0E+07, 56 08 => 1.0E+08, 57 09 => 1.0E+09, 58 10 => 1.0E+10, 59 11 => 1.0E+11, 60 12 => 1.0E+12, 61 13 => 1.0E+13, 62 14 => 1.0E+14, 63 15 => 1.0E+15, 64 16 => 1.0E+16, 65 17 => 1.0E+17, 66 18 => 1.0E+18, 67 19 => 1.0E+19, 68 20 => 1.0E+20, 69 21 => 1.0E+21, 70 22 => 1.0E+22); 71 72end System.Powten_Table; 73