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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- G N A T . B Y T E _ S W A P P I N G --
-- --
-- B o d y --
-- --
-- Copyright (C) 2006-2007, AdaCore --
-- --
-- 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, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, 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. --
-- --
------------------------------------------------------------------------------
-- This is a machine-specific version of this package.
-- It uses instructions available on Intel 486 processors (or later).
with Interfaces; use Interfaces;
with System.Machine_Code; use System.Machine_Code;
with Ada.Unchecked_Conversion;
package body GNAT.Byte_Swapping is
-----------------------
-- Local Subprograms --
-----------------------
function Swapped32 (Value : Unsigned_32) return Unsigned_32;
pragma Inline_Always (Swapped32);
--------------
-- Swapped2 --
--------------
function Swapped2 (Input : Item) return Item is
function As_U16 is new Ada.Unchecked_Conversion
(Source => Item, Target => Unsigned_16);
function As_Item is new Ada.Unchecked_Conversion
(Source => Unsigned_16, Target => Item);
X : Unsigned_16 := As_U16 (Input);
begin
Asm ("xchgb %b0,%h0",
Unsigned_16'Asm_Output ("=q", X),
Unsigned_16'Asm_Input ("0", X));
return As_Item (X);
end Swapped2;
--------------
-- Swapped4 --
--------------
function Swapped4 (Input : Item) return Item is
function As_U32 is new Ada.Unchecked_Conversion
(Source => Item, Target => Unsigned_32);
function As_Item is new Ada.Unchecked_Conversion
(Source => Unsigned_32, Target => Item);
X : Unsigned_32 := As_U32 (Input);
begin
Asm ("bswap %0",
Unsigned_32'Asm_Output ("=r", X),
Unsigned_32'Asm_Input ("0", X));
return As_Item (X);
end Swapped4;
--------------
-- Swapped8 --
--------------
function Swapped8 (Input : Item) return Item is
function As_U64 is new Ada.Unchecked_Conversion
(Source => Item, Target => Unsigned_64);
X : constant Unsigned_64 := As_U64 (Input);
type Two_Words is array (0 .. 1) of Unsigned_32;
for Two_Words'Component_Size use Unsigned_32'Size;
function As_Item is new Ada.Unchecked_Conversion
(Source => Two_Words, Target => Item);
Result : Two_Words;
begin
Asm ("xchgl %0,%1",
Outputs =>
(Unsigned_32'Asm_Output ("=r", Result (0)),
Unsigned_32'Asm_Output ("=r", Result (1))),
Inputs =>
(Unsigned_32'Asm_Input ("0",
Swapped32 (Unsigned_32 (X and 16#0000_0000_FFFF_FFFF#))),
Unsigned_32'Asm_Input ("1",
Swapped32 (Unsigned_32 (Shift_Right (X, 32))))));
return As_Item (Result);
end Swapped8;
-----------
-- Swap2 --
-----------
procedure Swap2 (Location : System.Address) is
X : Unsigned_16;
for X'Address use Location;
begin
Asm ("xchgb %b0,%h0",
Unsigned_16'Asm_Output ("=q", X),
Unsigned_16'Asm_Input ("0", X));
end Swap2;
-----------
-- Swap4 --
-----------
procedure Swap4 (Location : System.Address) is
X : Unsigned_32;
for X'Address use Location;
begin
Asm ("bswap %0",
Unsigned_32'Asm_Output ("=r", X),
Unsigned_32'Asm_Input ("0", X));
end Swap4;
---------------
-- Swapped32 --
---------------
function Swapped32 (Value : Unsigned_32) return Unsigned_32 is
X : Unsigned_32 := Value;
begin
Asm ("bswap %0",
Unsigned_32'Asm_Output ("=r", X),
Unsigned_32'Asm_Input ("0", X));
return X;
end Swapped32;
-----------
-- Swap8 --
-----------
procedure Swap8 (Location : System.Address) is
X : Unsigned_64;
for X'Address use Location;
type Two_Words is array (0 .. 1) of Unsigned_32;
for Two_Words'Component_Size use Unsigned_32'Size;
Words : Two_Words;
for Words'Address use Location;
begin
Asm ("xchgl %0,%1",
Outputs =>
(Unsigned_32'Asm_Output ("=r", Words (0)),
Unsigned_32'Asm_Output ("=r", Words (1))),
Inputs =>
(Unsigned_32'Asm_Input ("0",
Swapped32 (Unsigned_32 (X and 16#0000_0000_FFFF_FFFF#))),
Unsigned_32'Asm_Input ("1",
Swapped32 (Unsigned_32 (Shift_Right (X, 32))))));
end Swap8;
end GNAT.Byte_Swapping;
|
