1 /************************************************************************************

2

3 Filename : OVR_Atomic.cpp

4 Content : Contains atomic operations and inline fastest locking

5 functionality. Will contain #ifdefs for OS efficiency.

6 Have non-thread-safe implementation if not available.

7 Created : September 19, 2012

8 Notes :

9

10 Copyright : Copyright 2012 Oculus VR, Inc. All Rights reserved.

11

12 Use of this software is subject to the terms of the Oculus license

13 agreement provided at the time of installation or download, or which

14 otherwise accompanies this software in either electronic or hard copy form.

15

16 ************************************************************************************/

17

18 #include "OVR_Atomic.h"

19

20 #ifdef OVR_ENABLE_THREADS

21

22 // Include Windows 8-Metro compatible Synchronization API

23 #if defined(OVR_OS_WIN32) && defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8)

24 #include <synchapi.h>

25 #endif

26

27

28 namespace OVR {

29

30 // ***** Windows Lock implementation

31

32 #if defined(OVR_OS_WIN32)

33

34 // ***** Standard Win32 Lock implementation

35

36 // Constructors

37 Lock::Lock(unsigned spinCount)

38 {

39 #if defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8)

40 // On Windows 8 we use InitializeCriticalSectionEx due to Metro-Compatibility

41 InitializeCriticalSectionEx(&cs, spinCount,

42 OVR_DEBUG_SELECT(NULL, CRITICAL_SECTION_NO_DEBUG_INFO));

43 #else

44 // Spin count init critical section function prototype for Window NT

45 typedef BOOL (WINAPI *Function_InitializeCriticalSectionAndSpinCount)

46 (LPCRITICAL_SECTION lpCriticalSection, DWORD dwSpinCount);

47

48

49 // Try to load function dynamically so that we don't require NT

50 // On Windows NT we will use InitializeCriticalSectionAndSpinCount

51 static bool initTried = 0;

52 static Function_InitializeCriticalSectionAndSpinCount pInitFn = 0;

53

54 if (!initTried)

55 {

56 HMODULE hmodule = ::LoadLibrary(OVR_STR("kernel32.dll"));

57 pInitFn = (Function_InitializeCriticalSectionAndSpinCount)

58 ::GetProcAddress(hmodule, "InitializeCriticalSectionAndSpinCount");

59 initTried = true;

60 }

61

62 // Initialize the critical section

63 if (pInitFn)

64 pInitFn(&cs, spinCount);

65 else

66 ::InitializeCriticalSection(&cs);

67 #endif

68

69 }

70

71

72 Lock::~Lock()

73 {

74 DeleteCriticalSection(&cs);

75 }

76

77

78 #endif

79

80 } // OVR

81

82 #endif // OVR_ENABLE_THREADS