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Diffstat (limited to 'gcc-4.9/gcc/ada/s-expllu.adb')
| -rw-r--r-- | gcc-4.9/gcc/ada/s-expllu.adb | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/ada/s-expllu.adb b/gcc-4.9/gcc/ada/s-expllu.adb new file mode 100644 index 000000000..23ca437e5 --- /dev/null +++ b/gcc-4.9/gcc/ada/s-expllu.adb @@ -0,0 +1,74 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- S Y S T E M . X P _ B M L -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2009 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 3, 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. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- 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_LLU is + + ---------------------------- + -- Exp_Long_Long_Unsigned -- + ---------------------------- + + function Exp_Long_Long_Unsigned + (Left : Long_Long_Unsigned; + Right : Natural) + return Long_Long_Unsigned + is + Result : Long_Long_Unsigned := 1; + Factor : Long_Long_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_Long_Long_Unsigned; + +end System.Exp_LLU; |