| 1 |
706 |
jeremybenn |
------------------------------------------------------------------------------
|
| 2 |
|
|
-- --
|
| 3 |
|
|
-- GNAT RUN-TIME COMPONENTS --
|
| 4 |
|
|
-- --
|
| 5 |
|
|
-- S Y S T E M . A T O M I C _ C O U N T E R S --
|
| 6 |
|
|
-- --
|
| 7 |
|
|
-- B o d y --
|
| 8 |
|
|
-- --
|
| 9 |
|
|
-- Copyright (C) 2011, 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 implementation of the package for x86 processor. GCC can't generate
|
| 33 |
|
|
-- code for atomic builtins for 386 CPU. Only increment/decrement instructions
|
| 34 |
|
|
-- are supported, thus this implementaton uses machine code insertions to
|
| 35 |
|
|
-- access the necessary instructions.
|
| 36 |
|
|
|
| 37 |
|
|
with System.Machine_Code;
|
| 38 |
|
|
|
| 39 |
|
|
package body System.Atomic_Counters is
|
| 40 |
|
|
|
| 41 |
|
|
-- Add comments showing in normal asm language what we generate???
|
| 42 |
|
|
|
| 43 |
|
|
---------------
|
| 44 |
|
|
-- Decrement --
|
| 45 |
|
|
---------------
|
| 46 |
|
|
|
| 47 |
|
|
function Decrement (Item : in out Atomic_Counter) return Boolean is
|
| 48 |
|
|
Aux : Boolean;
|
| 49 |
|
|
|
| 50 |
|
|
begin
|
| 51 |
|
|
System.Machine_Code.Asm
|
| 52 |
|
|
(Template =>
|
| 53 |
|
|
"lock%; decl" & ASCII.HT & "%0" & ASCII.LF & ASCII.HT
|
| 54 |
|
|
& "sete %1",
|
| 55 |
|
|
Outputs =>
|
| 56 |
|
|
(Unsigned_32'Asm_Output ("=m", Item.Value),
|
| 57 |
|
|
Boolean'Asm_Output ("=qm", Aux)),
|
| 58 |
|
|
Inputs => Unsigned_32'Asm_Input ("m", Item.Value),
|
| 59 |
|
|
Volatile => True);
|
| 60 |
|
|
|
| 61 |
|
|
return Aux;
|
| 62 |
|
|
end Decrement;
|
| 63 |
|
|
|
| 64 |
|
|
---------------
|
| 65 |
|
|
-- Increment --
|
| 66 |
|
|
---------------
|
| 67 |
|
|
|
| 68 |
|
|
procedure Increment (Item : in out Atomic_Counter) is
|
| 69 |
|
|
begin
|
| 70 |
|
|
System.Machine_Code.Asm
|
| 71 |
|
|
(Template => "lock%; incl" & ASCII.HT & "%0",
|
| 72 |
|
|
Outputs => Unsigned_32'Asm_Output ("=m", Item.Value),
|
| 73 |
|
|
Inputs => Unsigned_32'Asm_Input ("m", Item.Value),
|
| 74 |
|
|
Volatile => True);
|
| 75 |
|
|
end Increment;
|
| 76 |
|
|
|
| 77 |
|
|
------------
|
| 78 |
|
|
-- Is_One --
|
| 79 |
|
|
------------
|
| 80 |
|
|
|
| 81 |
|
|
function Is_One (Item : Atomic_Counter) return Boolean is
|
| 82 |
|
|
begin
|
| 83 |
|
|
return Item.Value = 1;
|
| 84 |
|
|
end Is_One;
|
| 85 |
|
|
|
| 86 |
|
|
end System.Atomic_Counters;
|
