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| author | Richard Kenner <kenner@gcc.gnu.org> | 2001-10-02 10:30:19 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 2001-10-02 10:30:19 -0400 |
| commit | cacbc3505bac280b8db4f7d08a4a4b44ab69c0be (patch) | |
| tree | 86d33ed164722c539e5c03eb27ae96b8b7667e75 /gcc/ada/s-expuns.adb | |
| parent | 19235870adf79a3422aed017819c537f1d1375ac (diff) | |
| download | gcc-cacbc3505bac280b8db4f7d08a4a4b44ab69c0be.tar.gz | |
New Language: Ada
From-SVN: r45957
Diffstat (limited to 'gcc/ada/s-expuns.adb')
| -rw-r--r-- | gcc/ada/s-expuns.adb | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/gcc/ada/s-expuns.adb b/gcc/ada/s-expuns.adb new file mode 100644 index 00000000000..a02a6994cb4 --- /dev/null +++ b/gcc/ada/s-expuns.adb @@ -0,0 +1,77 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUNTIME COMPONENTS -- +-- -- +-- S Y S T E M . E X P _ U N S -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.10 $ -- +-- -- +-- 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. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +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; |