1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . X P _ B M L --
10 -- Copyright (C) 1992,1993,1994 Free Software Foundation, Inc. --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNAT; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNAT was originally developed by the GNAT team at New York University. --
31 -- Extensive contributions were provided by Ada Core Technologies Inc. --
33 ------------------------------------------------------------------------------
35 with System.Unsigned_Types; use System.Unsigned_Types;
37 package body System.Exp_LLU is
39 ----------------------------
40 -- Exp_Long_Long_Unsigned --
41 ----------------------------
43 function Exp_Long_Long_Unsigned
44 (Left : Long_Long_Unsigned;
46 return Long_Long_Unsigned
48 Result : Long_Long_Unsigned := 1;
49 Factor : Long_Long_Unsigned := Left;
50 Exp : Natural := Right;
53 -- We use the standard logarithmic approach, Exp gets shifted right
54 -- testing successive low order bits and Factor is the value of the
55 -- base raised to the next power of 2.
57 -- Note: it is not worth special casing the cases of base values -1,0,+1
58 -- since the expander does this when the base is a literal, and other
59 -- cases will be extremely rare.
63 if Exp rem 2 /= 0 then
64 Result := Result * Factor;
69 Factor := Factor * Factor;
75 end Exp_Long_Long_Unsigned;