File : s-mantis.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- S Y S T E M . M A N T I S S A --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1996-2014, 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 -- --
19 -- --
20 -- --
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 package body System.Mantissa is
33
34 --------------------
35 -- Mantissa_Value --
36 --------------------
37
38 function Mantissa_Value (First, Last : Integer) return Natural is
39 Result : Natural := 0;
40
41 Val : Integer := Integer'Max (abs First - 1, abs Last);
42 -- Note: First-1 allows for twos complement largest neg number
43
44 begin
45 while Val /= 0 loop
46 Val := Val / 2;
47 Result := Result + 1;
48 end loop;
49
50 return Result;
51 end Mantissa_Value;
52
53 end System.Mantissa;