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) 1996-2009 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
32package 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
53end System.Mantissa;
54