------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- S Y S T E M . E X P _ U N S -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-1997 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with System.Unsigned_Types; use System.Unsigned_Types; package body System.Exp_Uns is ------------------ -- Exp_Unsigned -- ------------------ function Exp_Unsigned (Left : Unsigned; Right : Natural) return Unsigned is Result : Unsigned := 1; Factor : Unsigned := Left; Exp : Natural := Right; begin -- We use the standard logarithmic approach, Exp gets shifted right -- testing successive low order bits and Factor is the value of the -- base raised to the next power of 2. -- Note: it is not worth special casing the cases of base values -1,0,+1 -- since the expander does this when the base is a literal, and other -- cases will be extremely rare. if Exp /= 0 then loop if Exp rem 2 /= 0 then Result := Result * Factor; end if; Exp := Exp / 2; exit when Exp = 0; Factor := Factor * Factor; end loop; end if; return Result; end Exp_Unsigned; end System.Exp_Uns;