gcc/ada/g-bytswa.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                    G N A T . B Y T E _ S W A P P I N G                   --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 2006-2012, AdaCore                     --
  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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a general implementation that uses GCC intrinsics to take
  33 --  advantage of any machine-specific instructions.
  34
  35 with Ada.Unchecked_Conversion; use Ada;
  36
  37 with System.Byte_Swapping; use System.Byte_Swapping;
  38
  39 package body GNAT.Byte_Swapping is
  40
  41    --------------
  42    -- Swapped2 --
  43    --------------
  44
  45    function Swapped2 (Input : Item) return Item is
  46       function As_U16 is new Unchecked_Conversion (Item, U16);
  47       function As_Item is new Unchecked_Conversion (U16, Item);
  48       pragma Compile_Time_Error (Item'Max_Size_In_Storage_Elements /= 2,
  49         "storage size must be 2 bytes");
  50    begin
  51       return As_Item (Bswap_16 (As_U16 (Input)));
  52    end Swapped2;
  53
  54    --------------
  55    -- Swapped4 --
  56    --------------
  57
  58    function Swapped4 (Input : Item) return Item is
  59       function As_U32 is new Unchecked_Conversion (Item, U32);
  60       function As_Item is new Unchecked_Conversion (U32, Item);
  61       pragma Compile_Time_Error (Item'Max_Size_In_Storage_Elements /= 4,
  62         "storage size must be 4 bytes");
  63    begin
  64       return As_Item (Bswap_32 (As_U32 (Input)));
  65    end Swapped4;
  66
  67    --------------
  68    -- Swapped8 --
  69    --------------
  70
  71    function Swapped8 (Input : Item) return Item is
  72       function As_U64 is new Unchecked_Conversion (Item, U64);
  73       function As_Item is new Unchecked_Conversion (U64, Item);
  74       pragma Compile_Time_Error (Item'Max_Size_In_Storage_Elements /= 8,
  75         "storage size must be 8 bytes");
  76    begin
  77       return As_Item (Bswap_64 (As_U64 (Input)));
  78    end Swapped8;
  79
  80    -----------
  81    -- Swap2 --
  82    -----------
  83
  84    procedure Swap2 (Location : System.Address) is
  85       X : U16;
  86       for X'Address use Location;
  87    begin
  88       X := Bswap_16 (X);
  89    end Swap2;
  90
  91    -----------
  92    -- Swap4 --
  93    -----------
  94
  95    procedure Swap4 (Location : System.Address) is
  96       X : U32;
  97       for X'Address use Location;
  98    begin
  99       X := Bswap_32 (X);
 100    end Swap4;
 101
 102    -----------
 103    -- Swap8 --
 104    -----------
 105
 106    procedure Swap8 (Location : System.Address) is
 107       X : U64;
 108       for X'Address use Location;
 109    begin
 110       X := Bswap_64 (X);
 111    end Swap8;
 112
 113 end GNAT.Byte_Swapping;