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Diffstat (limited to 'gcc-4.8.3/gcc/ada/s-bitops.adb')
| -rw-r--r-- | gcc-4.8.3/gcc/ada/s-bitops.adb | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/gcc-4.8.3/gcc/ada/s-bitops.adb b/gcc-4.8.3/gcc/ada/s-bitops.adb new file mode 100644 index 000000000..dbf30ddd5 --- /dev/null +++ b/gcc-4.8.3/gcc/ada/s-bitops.adb @@ -0,0 +1,220 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- S Y S T E M . B I T _ O P S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1996-2010, 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. -- +-- -- +------------------------------------------------------------------------------ + +pragma Compiler_Unit; + +with System; use System; +with System.Unsigned_Types; use System.Unsigned_Types; + +with Ada.Exceptions; use Ada.Exceptions; +with Ada.Unchecked_Conversion; + +package body System.Bit_Ops is + + subtype Bits_Array is System.Unsigned_Types.Packed_Bytes1 (Positive); + -- Dummy array type used to interpret the address values. We use the + -- unaligned version always, since this will handle both the aligned and + -- unaligned cases, and we always do these operations by bytes anyway. + -- Note: we use a ones origin array here so that the computations of the + -- length in bytes work correctly (give a non-negative value) for the + -- case of zero length bit strings). Note that we never allocate any + -- objects of this type (we can't because they would be absurdly big). + + type Bits is access Bits_Array; + -- This is the actual type into which address values are converted + + function To_Bits is new Ada.Unchecked_Conversion (Address, Bits); + + LE : constant := Standard'Default_Bit_Order; + -- Static constant set to 0 for big-endian, 1 for little-endian + + -- The following is an array of masks used to mask the final byte, either + -- at the high end (big-endian case) or the low end (little-endian case). + + Masks : constant array (1 .. 7) of Packed_Byte := ( + (1 - LE) * 2#1000_0000# + LE * 2#0000_0001#, + (1 - LE) * 2#1100_0000# + LE * 2#0000_0011#, + (1 - LE) * 2#1110_0000# + LE * 2#0000_0111#, + (1 - LE) * 2#1111_0000# + LE * 2#0000_1111#, + (1 - LE) * 2#1111_1000# + LE * 2#0001_1111#, + (1 - LE) * 2#1111_1100# + LE * 2#0011_1111#, + (1 - LE) * 2#1111_1110# + LE * 2#0111_1111#); + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Raise_Error; + pragma No_Return (Raise_Error); + -- Raise Constraint_Error, complaining about unequal lengths + + ------------- + -- Bit_And -- + ------------- + + procedure Bit_And + (Left : Address; + Llen : Natural; + Right : Address; + Rlen : Natural; + Result : Address) + is + LeftB : constant Bits := To_Bits (Left); + RightB : constant Bits := To_Bits (Right); + ResultB : constant Bits := To_Bits (Result); + + begin + if Llen /= Rlen then + Raise_Error; + end if; + + for J in 1 .. (Rlen + 7) / 8 loop + ResultB (J) := LeftB (J) and RightB (J); + end loop; + end Bit_And; + + ------------ + -- Bit_Eq -- + ------------ + + function Bit_Eq + (Left : Address; + Llen : Natural; + Right : Address; + Rlen : Natural) return Boolean + is + LeftB : constant Bits := To_Bits (Left); + RightB : constant Bits := To_Bits (Right); + + begin + if Llen /= Rlen then + return False; + + else + declare + BLen : constant Natural := Llen / 8; + Bitc : constant Natural := Llen mod 8; + + begin + if LeftB (1 .. BLen) /= RightB (1 .. BLen) then + return False; + + elsif Bitc /= 0 then + return + ((LeftB (BLen + 1) xor RightB (BLen + 1)) + and Masks (Bitc)) = 0; + + else -- Bitc = 0 + return True; + end if; + end; + end if; + end Bit_Eq; + + ------------- + -- Bit_Not -- + ------------- + + procedure Bit_Not + (Opnd : System.Address; + Len : Natural; + Result : System.Address) + is + OpndB : constant Bits := To_Bits (Opnd); + ResultB : constant Bits := To_Bits (Result); + + begin + for J in 1 .. (Len + 7) / 8 loop + ResultB (J) := not OpndB (J); + end loop; + end Bit_Not; + + ------------ + -- Bit_Or -- + ------------ + + procedure Bit_Or + (Left : Address; + Llen : Natural; + Right : Address; + Rlen : Natural; + Result : Address) + is + LeftB : constant Bits := To_Bits (Left); + RightB : constant Bits := To_Bits (Right); + ResultB : constant Bits := To_Bits (Result); + + begin + if Llen /= Rlen then + Raise_Error; + end if; + + for J in 1 .. (Rlen + 7) / 8 loop + ResultB (J) := LeftB (J) or RightB (J); + end loop; + end Bit_Or; + + ------------- + -- Bit_Xor -- + ------------- + + procedure Bit_Xor + (Left : Address; + Llen : Natural; + Right : Address; + Rlen : Natural; + Result : Address) + is + LeftB : constant Bits := To_Bits (Left); + RightB : constant Bits := To_Bits (Right); + ResultB : constant Bits := To_Bits (Result); + + begin + if Llen /= Rlen then + Raise_Error; + end if; + + for J in 1 .. (Rlen + 7) / 8 loop + ResultB (J) := LeftB (J) xor RightB (J); + end loop; + end Bit_Xor; + + ----------------- + -- Raise_Error -- + ----------------- + + procedure Raise_Error is + begin + Raise_Exception + (Constraint_Error'Identity, "operand lengths are unequal"); + end Raise_Error; + +end System.Bit_Ops; |