compareAndSwap.h

00001 
00002 //  Copyright (C) 2007, 2008 Tim Blechmann & Thomas Grill
00003 //
00004 //  Distributed under the Boost Software License, Version 1.0. (See
00005 //  accompanying file LICENSE_1_0.txt or copy at
00006 //  http://www.boost.org/LICENSE_1_0.txt)
00007 
00008 //  Disclaimer: Not a Boost library.
00009 
00010 /* Copyright (c) 2008-2009, Stefan Eilemann <eile@equalizergraphics.com> 
00011    Modifications to use within eq::base namespace and naming conventions.
00012    Original at http://tim.klingt.org/git?p=boost_lockfree.git;a=tree
00013 */
00014 
00015 #ifndef EQBASE_COMPAREANDSWAP_H
00016 #define EQBASE_COMPAREANDSWAP_H
00017 
00018 #include <eq/base/base.h>
00019 
00020 #if defined(_MSC_VER) && (_MSC_VER >= 1300)
00021 #  include <intrin.h>
00022 #  pragma intrinsic(_ReadWriteBarrier)
00023 #endif
00024 
00025 #ifdef Darwin
00026 #  include <libkern/OSAtomic.h>
00027 #endif
00028 
00029 namespace eq
00030 {
00031 namespace base
00032 {
00033 
00034 #if (defined(__GNUC__) && \
00035     ( (__GNUC__ > 4) || ((__GNUC__ >= 4) && (__GNUC_MINOR__ >= 1)) )) || \
00036     defined(_MSC_VER) || defined(_WIN32) || defined(__APPLE__) || \
00037     defined(AO_HAVE_compare_and_swap_full)
00038 #  define EQ_HAS_COMPARE_AND_SWAP
00039 
00041 inline void memoryBarrier()
00042 {
00043 #if defined(__GNUC__) && \
00044     ( (__GNUC__ > 4) || ((__GNUC__ >= 4) && (__GNUC_MINOR__ >= 1)) )
00045     __sync_synchronize();
00046 #elif defined(_MSC_VER) && (_MSC_VER >= 1300)
00047     _ReadWriteBarrier();
00048 #elif defined(__APPLE__)
00049     OSMemoryBarrier();
00050 #elif defined(AO_HAVE_nop_full)
00051     AO_nop_full();
00052 #elif defined( __PPC__ )
00053     asm volatile("sync":::"memory");
00054 #elif defined( __i386__ ) || defined( __i486__ ) || defined( __i586__ ) || \
00055       defined( __i686__ ) || defined( __x86_64__ )
00056     asm volatile("mfence":::"memory");
00057 #else
00058 #   warning "no memory barrier implemented for this platform"
00059 #endif
00060 }
00061 
00067 template <class C, class D>
00068 inline bool compareAndSwap(volatile C * addr, D old, D nw)
00069 {
00070 #if defined(__GNUC__) && \
00071     ( (__GNUC__ > 4) || ((__GNUC__ >= 4) && (__GNUC_MINOR__ >= 1)) )
00072     return __sync_bool_compare_and_swap(addr, old, nw);
00073 #elif defined(_MSC_VER)
00074     return _InterlockedCompareExchange(addr,nw,old) == old;
00075 #elif defined(_WIN32)
00076     return InterlockedCompareExchange(addr,nw,old) == old;
00077 #elif defined(__APPLE__)
00078     return OSAtomicCompareAndSwap32((int32_t) old, (int32_t)nw, (int32_t*)addr);
00079 #elif defined(AO_HAVE_compare_and_swap_full)
00080     return AO_compare_and_swap_full(reinterpret_cast<volatile AO_t*>(addr),
00081                                     reinterpret_cast<AO_t>(old),
00082                                     reinterpret_cast<AO_t>(nw));
00083 #else
00084 #  warning ("CompareAndSwap emulation")
00085 #  include <eq/base/lock.h>           // used in inline function
00086 #  include <eq/base/scopedMutex.h>    // used in inline function
00087 
00088     static Lock guard;
00089     ScopedMutex lock(guard);
00090 
00091     if (*addr == old)
00092     {
00093         *addr = nw;
00094         return true;
00095     }
00096     else
00097         return false;
00098 #endif
00099 }
00100 
00101 #endif
00102 }
00103 
00104 }
00105 #endif // EQBASE_COMPAREANDSWAP_H