------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . M U L T I P R O C E S S O R S . S P I N _ L O C K S --
-- --
-- S p e c --
-- --
-- Copyright (C) 2010-2023, AdaCore --
-- --
-- GNARL 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. GNARL 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/>. --
-- --
------------------------------------------------------------------------------
package System.Multiprocessors.Spin_Locks is
pragma Preelaborate;
---------------
-- Spin lock --
---------------
type Atomic_Flag is mod 2**8;
pragma Atomic (Atomic_Flag);
Unlocked : constant Atomic_Flag := 0;
type Spin_Lock is limited record
Flag : aliased Atomic_Flag := Unlocked;
end record;
-- The default value of a Spin_Lock is unlocked
procedure Lock (Slock : in out Spin_Lock);
pragma Inline (Lock);
-- Loop until lock is acquired
function Locked (Slock : Spin_Lock) return Boolean;
pragma Inline (Locked);
-- Return the current state of the lock
procedure Try_Lock (Slock : in out Spin_Lock; Succeeded : out Boolean);
pragma Inline (Try_Lock);
-- Return True if the lock has been acquired, otherwise don't wait for the
-- lock and return False.
procedure Unlock (Slock : in out Spin_Lock);
pragma Inline (Unlock);
-- Release the lock
end System.Multiprocessors.Spin_Locks;