1 files changed, 139 insertions, 0 deletions
diff --git a/LibOVRKernel/Src/Kernel/OVR_Atomic.cpp b/LibOVRKernel/Src/Kernel/OVR_Atomic.cpp
new file mode 100644
index 0000000..f7cf9a6
--- /dev/null
+++ b/LibOVRKernel/Src/Kernel/OVR_Atomic.cpp
@@ -0,0 +1,139 @@
+/************************************************************************************
+
+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, LLC All Rights reserved.
+
+Licensed under the Oculus VR Rift SDK License Version 3.2 (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-3.2 
+
+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_MS) && defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8)
+#include <synchapi.h>
+#endif
+
+
+namespace OVR {
+
+// ***** Windows Lock implementation
+
+#if defined(OVR_OS_MS)
+
+// ***** 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, (DWORD)spinCount,
+                                   OVR_DEBUG_SELECT(NULL, CRITICAL_SECTION_NO_DEBUG_INFO));
+    #else
+        ::InitializeCriticalSectionAndSpinCount(&cs, (DWORD)spinCount); // This is available with WindowsXP+.
+    #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 == (int)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 != (int)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