| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- System.Atomic_Operations.Exchange -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 2019-2022, 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with System.Atomic_Primitives; use System.Atomic_Primitives; |
| with Interfaces.C; |
| |
| package body System.Atomic_Operations.Exchange is |
| |
| --------------------- |
| -- Atomic_Exchange -- |
| --------------------- |
| |
| function Atomic_Exchange |
| (Item : aliased in out Atomic_Type; |
| Value : Atomic_Type) return Atomic_Type |
| is |
| pragma Warnings (Off); |
| function Atomic_Exchange |
| (Ptr : System.Address; |
| Val : Atomic_Type; |
| Model : Mem_Model := Seq_Cst) return Atomic_Type; |
| pragma Import (Intrinsic, Atomic_Exchange, "__atomic_exchange_n"); |
| pragma Warnings (On); |
| |
| begin |
| if Atomic_Type'Object_Size in 8 | 16 | 32 | 64 then |
| return Atomic_Exchange (Item'Address, Value); |
| else |
| raise Program_Error; |
| end if; |
| end Atomic_Exchange; |
| |
| --------------------------------- |
| -- Atomic_Compare_And_Exchange -- |
| --------------------------------- |
| |
| function Atomic_Compare_And_Exchange |
| (Item : aliased in out Atomic_Type; |
| Prior : aliased in out Atomic_Type; |
| Desired : Atomic_Type) return Boolean |
| is |
| pragma Warnings (Off); |
| function Atomic_Compare_Exchange |
| (Ptr : System.Address; |
| Expected : System.Address; |
| Desired : Atomic_Type; |
| Weak : Boolean := False; |
| Success_Model : Mem_Model := Seq_Cst; |
| Failure_Model : Mem_Model := Seq_Cst) return Boolean; |
| pragma Import |
| (Intrinsic, Atomic_Compare_Exchange, "__atomic_compare_exchange_n"); |
| pragma Warnings (On); |
| |
| begin |
| if Atomic_Type'Object_Size in 8 | 16 | 32 | 64 then |
| return Atomic_Compare_Exchange (Item'Address, Prior'Address, Desired); |
| else |
| raise Program_Error; |
| end if; |
| end Atomic_Compare_And_Exchange; |
| |
| ------------------ |
| -- Is_Lock_Free -- |
| ------------------ |
| |
| function Is_Lock_Free (Item : aliased Atomic_Type) return Boolean is |
| pragma Unreferenced (Item); |
| use type Interfaces.C.size_t; |
| begin |
| return Atomic_Always_Lock_Free (Atomic_Type'Object_Size / 8); |
| end Is_Lock_Free; |
| |
| end System.Atomic_Operations.Exchange; |
