File : s-powtab.ads
------------------------------------------------------------------------------
-- --
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------------------------------------------------------------------------------
-- 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;