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author | Sven Gothel <[email protected]> | 2014-06-19 17:03:28 +0200 |
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committer | Sven Gothel <[email protected]> | 2014-06-19 17:03:28 +0200 |
commit | d9a584844a60542519d813b5dc1a62428f14a0ae (patch) | |
tree | 942c10a5ebcd0aab65e9d6facb59778468f39d3b /LibOVR/Src/Kernel/OVR_Atomic.cpp |
Add OculusSDK 0.3.2 Linux Source Code w/o Samples, docs or binaries (libs or tools)
Diffstat (limited to 'LibOVR/Src/Kernel/OVR_Atomic.cpp')
-rw-r--r-- | LibOVR/Src/Kernel/OVR_Atomic.cpp | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/LibOVR/Src/Kernel/OVR_Atomic.cpp b/LibOVR/Src/Kernel/OVR_Atomic.cpp new file mode 100644 index 0000000..9ea6e76 --- /dev/null +++ b/LibOVR/Src/Kernel/OVR_Atomic.cpp @@ -0,0 +1,162 @@ +/************************************************************************************ + +Filename : OVR_Atomic.cpp +Content : Contains atomic operations and inline fastest locking + functionality. Will contain #ifdefs for OS efficiency. + Have non-thread-safe implementation if not available. +Created : September 19, 2012 +Notes : + +Copyright : Copyright 2014 Oculus VR, Inc. All Rights reserved. + +Licensed under the Oculus VR Rift SDK License Version 3.1 (the "License"); +you may not use the Oculus VR Rift SDK except in compliance with the License, +which is provided at the time of installation or download, or which +otherwise accompanies this software in either electronic or hard copy form. + +You may obtain a copy of the License at + +http://www.oculusvr.com/licenses/LICENSE-3.1 + +Unless required by applicable law or agreed to in writing, the Oculus VR SDK +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. + +************************************************************************************/ + +#include "OVR_Atomic.h" +#include "OVR_Allocator.h" + +#ifdef OVR_ENABLE_THREADS + +// Include Windows 8-Metro compatible Synchronization API +#if defined(OVR_OS_WIN32) && defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8) +#include <synchapi.h> +#endif + + +namespace OVR { + +// ***** Windows Lock implementation + +#if defined(OVR_OS_WIN32) + +// ***** Standard Win32 Lock implementation + +// Constructors +Lock::Lock(unsigned spinCount) +{ +#if defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8) + // On Windows 8 we use InitializeCriticalSectionEx due to Metro-Compatibility + InitializeCriticalSectionEx(&cs, spinCount, + OVR_DEBUG_SELECT(NULL, CRITICAL_SECTION_NO_DEBUG_INFO)); +#else + // Spin count init critical section function prototype for Window NT + typedef BOOL (WINAPI *Function_InitializeCriticalSectionAndSpinCount) + (LPCRITICAL_SECTION lpCriticalSection, DWORD dwSpinCount); + + + // Try to load function dynamically so that we don't require NT + // On Windows NT we will use InitializeCriticalSectionAndSpinCount + static bool initTried = 0; + static Function_InitializeCriticalSectionAndSpinCount pInitFn = 0; + + if (!initTried) + { + HMODULE hmodule = ::LoadLibrary(OVR_STR("kernel32.dll")); + pInitFn = (Function_InitializeCriticalSectionAndSpinCount) + ::GetProcAddress(hmodule, "InitializeCriticalSectionAndSpinCount"); + initTried = true; + } + + // Initialize the critical section + if (pInitFn) + pInitFn(&cs, spinCount); + else + ::InitializeCriticalSection(&cs); +#endif + +} + + +Lock::~Lock() +{ + DeleteCriticalSection(&cs); +} + + +#endif + + +//------------------------------------------------------------------------------------- +// ***** SharedLock + +// This is a general purpose globally shared Lock implementation that should probably be +// moved to Kernel. +// May in theory busy spin-wait if we hit contention on first lock creation, +// but this shouldn't matter in practice since Lock* should be cached. + + +enum { LockInitMarker = 0xFFFFFFFF }; + +Lock* SharedLock::GetLockAddRef() +{ + int oldUseCount; + + do { + oldUseCount = UseCount; + if (oldUseCount == LockInitMarker) + continue; + + if (oldUseCount == 0) + { + // Initialize marker + if (AtomicOps<int>::CompareAndSet_Sync(&UseCount, 0, LockInitMarker)) + { + Construct<Lock>(Buffer); + do { } + while (!AtomicOps<int>::CompareAndSet_Sync(&UseCount, LockInitMarker, 1)); + return toLock(); + } + continue; + } + + } while (!AtomicOps<int>::CompareAndSet_NoSync(&UseCount, oldUseCount, oldUseCount + 1)); + + return toLock(); +} + +void SharedLock::ReleaseLock(Lock* plock) +{ + OVR_UNUSED(plock); + OVR_ASSERT(plock == toLock()); + + int oldUseCount; + + do { + oldUseCount = UseCount; + OVR_ASSERT(oldUseCount != LockInitMarker); + + if (oldUseCount == 1) + { + // Initialize marker + if (AtomicOps<int>::CompareAndSet_Sync(&UseCount, 1, LockInitMarker)) + { + Destruct<Lock>(toLock()); + + do { } + while (!AtomicOps<int>::CompareAndSet_Sync(&UseCount, LockInitMarker, 0)); + + return; + } + continue; + } + + } while (!AtomicOps<int>::CompareAndSet_NoSync(&UseCount, oldUseCount, oldUseCount - 1)); +} + +} // OVR + +#endif // OVR_ENABLE_THREADS |