1------------------------------------------------------------------------------ 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) 2011-2015, Free Software Foundation, Inc. -- 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 is version of the package, for use on platforms where this capability 33-- is not supported. All Atomic_Counter operations raises Program_Error, 34-- Atomic_Unsigned operations processed in non-atomic manner. 35 36package body System.Atomic_Counters is 37 38 --------------- 39 -- Decrement -- 40 --------------- 41 42 function Decrement (Item : in out Atomic_Counter) return Boolean is 43 begin 44 raise Program_Error; 45 return False; 46 end Decrement; 47 48 function Decrement (Item : aliased in out Atomic_Unsigned) return Boolean is 49 begin 50 -- Could not use Item := Item - 1; because it is disabled in spec. 51 Item := Atomic_Unsigned'Pred (Item); 52 return Item = 0; 53 end Decrement; 54 55 procedure Decrement (Item : aliased in out Atomic_Unsigned) is 56 begin 57 Item := Atomic_Unsigned'Pred (Item); 58 end Decrement; 59 60 --------------- 61 -- Increment -- 62 --------------- 63 64 procedure Increment (Item : in out Atomic_Counter) is 65 begin 66 raise Program_Error; 67 end Increment; 68 69 procedure Increment (Item : aliased in out Atomic_Unsigned) is 70 begin 71 Item := Atomic_Unsigned'Succ (Item); 72 end Increment; 73 74 ---------------- 75 -- Initialize -- 76 ---------------- 77 78 procedure Initialize (Item : out Atomic_Counter) is 79 begin 80 raise Program_Error; 81 end Initialize; 82 83 ------------ 84 -- Is_One -- 85 ------------ 86 87 function Is_One (Item : Atomic_Counter) return Boolean is 88 begin 89 raise Program_Error; 90 return False; 91 end Is_One; 92 93end System.Atomic_Counters; 94