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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . A T O M I C _ P R I M I T I V E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 2012, 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. --
-- --
------------------------------------------------------------------------------
package body System.Atomic_Primitives is
----------------------
-- Lock_Free_Read_8 --
----------------------
function Lock_Free_Read_8 (Ptr : Address) return uint8 is
begin
if uint8'Atomic_Always_Lock_Free then
return Atomic_Load_8 (Ptr, Acquire);
else
raise Program_Error;
end if;
end Lock_Free_Read_8;
-----------------------
-- Lock_Free_Read_16 --
-----------------------
function Lock_Free_Read_16 (Ptr : Address) return uint16 is
begin
if uint16'Atomic_Always_Lock_Free then
return Atomic_Load_16 (Ptr, Acquire);
else
raise Program_Error;
end if;
end Lock_Free_Read_16;
-----------------------
-- Lock_Free_Read_32 --
-----------------------
function Lock_Free_Read_32 (Ptr : Address) return uint32 is
begin
if uint32'Atomic_Always_Lock_Free then
return Atomic_Load_32 (Ptr, Acquire);
else
raise Program_Error;
end if;
end Lock_Free_Read_32;
-----------------------
-- Lock_Free_Read_64 --
-----------------------
function Lock_Free_Read_64 (Ptr : Address) return uint64 is
begin
if uint64'Atomic_Always_Lock_Free then
return Atomic_Load_64 (Ptr, Acquire);
else
raise Program_Error;
end if;
end Lock_Free_Read_64;
---------------------------
-- Lock_Free_Try_Write_8 --
---------------------------
function Lock_Free_Try_Write_8
(Ptr : Address;
Expected : in out uint8;
Desired : uint8) return Boolean
is
Actual : uint8;
begin
if Expected /= Desired then
if uint8'Atomic_Always_Lock_Free then
Actual := Sync_Compare_And_Swap_8 (Ptr, Expected, Desired);
else
raise Program_Error;
end if;
if Actual /= Expected then
Expected := Actual;
return False;
end if;
end if;
return True;
end Lock_Free_Try_Write_8;
----------------------------
-- Lock_Free_Try_Write_16 --
----------------------------
function Lock_Free_Try_Write_16
(Ptr : Address;
Expected : in out uint16;
Desired : uint16) return Boolean
is
Actual : uint16;
begin
if Expected /= Desired then
if uint16'Atomic_Always_Lock_Free then
Actual := Sync_Compare_And_Swap_16 (Ptr, Expected, Desired);
else
raise Program_Error;
end if;
if Actual /= Expected then
Expected := Actual;
return False;
end if;
end if;
return True;
end Lock_Free_Try_Write_16;
----------------------------
-- Lock_Free_Try_Write_32 --
----------------------------
function Lock_Free_Try_Write_32
(Ptr : Address;
Expected : in out uint32;
Desired : uint32) return Boolean
is
Actual : uint32;
begin
if Expected /= Desired then
if uint32'Atomic_Always_Lock_Free then
Actual := Sync_Compare_And_Swap_32 (Ptr, Expected, Desired);
else
raise Program_Error;
end if;
if Actual /= Expected then
Expected := Actual;
return False;
end if;
end if;
return True;
end Lock_Free_Try_Write_32;
----------------------------
-- Lock_Free_Try_Write_64 --
----------------------------
function Lock_Free_Try_Write_64
(Ptr : Address;
Expected : in out uint64;
Desired : uint64) return Boolean
is
Actual : uint64;
begin
if Expected /= Desired then
if uint64'Atomic_Always_Lock_Free then
Actual := Sync_Compare_And_Swap_64 (Ptr, Expected, Desired);
else
raise Program_Error;
end if;
if Actual /= Expected then
Expected := Actual;
return False;
end if;
end if;
return True;
end Lock_Free_Try_Write_64;
end System.Atomic_Primitives;
|
