gcc-cas.hpp
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00001 //  Copyright (c) 2011 Helge Bahmann
00002 //
00003 //  Distributed under the Boost Software License, Version 1.0.
00004 //  See accompanying file LICENSE_1_0.txt or copy at
00005 //  http://www.boost.org/LICENSE_1_0.txt)
00006 
00007 // Use the gnu builtin __sync_val_compare_and_swap to build
00008 // atomic operations for 32 bit and smaller.
00009 
00010 #ifndef BOOST_DETAIL_ATOMIC_GENERIC_CAS_HPP
00011 #define BOOST_DETAIL_ATOMIC_GENERIC_CAS_HPP
00012 
00013 #define BOOST_ATOMIC_CHAR_LOCK_FREE 2
00014 #define BOOST_ATOMIC_SHORT_LOCK_FREE 2
00015 #define BOOST_ATOMIC_INT_LOCK_FREE 2
00016 #define BOOST_ATOMIC_LONG_LOCK_FREE (sizeof(long) <= 4 ? 2 : 0)
00017 #define BOOST_ATOMIC_LLONG_LOCK_FREE (sizeof(long long) <= 4 ? 2 : 0)
00018 #define BOOST_ATOMIC_ADDRESS_LOCK_FREE (sizeof(void *) <= 4 ? 2 : 0)
00019 #define BOOST_ATOMIC_BOOL_LOCK_FREE 2
00020 
00021 namespace boost {
00022 
00023 #define BOOST_ATOMIC_THREAD_FENCE 2
00024 inline void
00025 atomic_thread_fence(memory_order order)
00026 {
00027         switch(order) {
00028                 case memory_order_relaxed:
00029                         break;
00030                 case memory_order_release:
00031                 case memory_order_consume:
00032                 case memory_order_acquire:
00033                 case memory_order_acq_rel:
00034                 case memory_order_seq_cst:
00035                         __sync_synchronize();
00036                         break;
00037         }
00038 }
00039 
00040 namespace detail {
00041 namespace atomic {
00042 
00043 static inline void
00044 platform_fence_before(memory_order)
00045 {
00046         /* empty, as compare_and_swap is synchronizing already */
00047 }
00048 
00049 static inline void
00050 platform_fence_after(memory_order)
00051 {
00052         /* empty, as compare_and_swap is synchronizing already */
00053 }
00054 
00055 static inline void
00056 platform_fence_before_store(memory_order order)
00057 {
00058         switch(order) {
00059                 case memory_order_relaxed:
00060                 case memory_order_acquire:
00061                 case memory_order_consume:
00062                         break;
00063                 case memory_order_release:
00064                 case memory_order_acq_rel:
00065                 case memory_order_seq_cst:
00066                         __sync_synchronize();
00067                         break;
00068         }
00069 }
00070 
00071 static inline void
00072 platform_fence_after_store(memory_order order)
00073 {
00074         if (order == memory_order_seq_cst)
00075                 __sync_synchronize();
00076 }
00077 
00078 static inline void
00079 platform_fence_after_load(memory_order order)
00080 {
00081         switch(order) {
00082                 case memory_order_relaxed:
00083                 case memory_order_release:
00084                         break;
00085                 case memory_order_consume:
00086                 case memory_order_acquire:
00087                 case memory_order_acq_rel:
00088                 case memory_order_seq_cst:
00089                         __sync_synchronize();
00090                         break;
00091         }
00092 }
00093 
00094 template<typename T>
00095 bool
00096 platform_cmpxchg32_strong(T & expected, T desired, volatile T * ptr)
00097 {
00098         T found = __sync_val_compare_and_swap(ptr, expected, desired);
00099         bool success = (found == expected);
00100         expected = found;
00101         return success;
00102 }
00103 
00104 }
00105 }
00106 }
00107 
00108 #include <boost/atomic/detail/cas32strong.hpp>
00109 
00110 #endif


rosatomic
Author(s): Josh Faust
autogenerated on Sat Jun 8 2019 20:43:34