1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUNTIME COMPONENTS -- 4-- -- 5-- S Y S T E M . X P _ B M L -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992,1993,1994 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 34with System.Unsigned_Types; use System.Unsigned_Types; 35 36package body System.Exp_LLU is 37 38 ---------------------------- 39 -- Exp_Long_Long_Unsigned -- 40 ---------------------------- 41 42 function Exp_Long_Long_Unsigned 43 (Left : Long_Long_Unsigned; 44 Right : Natural) 45 return Long_Long_Unsigned 46 is 47 Result : Long_Long_Unsigned := 1; 48 Factor : Long_Long_Unsigned := Left; 49 Exp : Natural := Right; 50 51 begin 52 -- We use the standard logarithmic approach, Exp gets shifted right 53 -- testing successive low order bits and Factor is the value of the 54 -- base raised to the next power of 2. 55 56 -- Note: it is not worth special casing the cases of base values -1,0,+1 57 -- since the expander does this when the base is a literal, and other 58 -- cases will be extremely rare. 59 60 if Exp /= 0 then 61 loop 62 if Exp rem 2 /= 0 then 63 Result := Result * Factor; 64 end if; 65 66 Exp := Exp / 2; 67 exit when Exp = 0; 68 Factor := Factor * Factor; 69 end loop; 70 end if; 71 72 return Result; 73 74 end Exp_Long_Long_Unsigned; 75 76end System.Exp_LLU; 77