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comparison src/atomic/SDL_spinlock.c @ 5230:5d01d426f2ea

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It's now possible to disable the fast atomic operations, at a huge performance penalty.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 07 Feb 2011 22:57:33 -0800
parents b938ad843e52
children b530ef003506
comparison
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5229:2178ffe17222 5230:5d01d426f2ea
20 slouken@libsdl.org 20 slouken@libsdl.org
21 */ 21 */
22 #include "SDL_stdinc.h" 22 #include "SDL_stdinc.h"
23 23
24 #include "SDL_atomic.h" 24 #include "SDL_atomic.h"
25 #include "SDL_mutex.h"
25 #include "SDL_timer.h" 26 #include "SDL_timer.h"
26 27
27 /* Don't do the check for Visual Studio 2005, it's safe here */ 28 /* Don't do the check for Visual Studio 2005, it's safe here */
28 #ifdef __WIN32__ 29 #ifdef __WIN32__
29 #include "../core/windows/SDL_windows.h" 30 #include "../core/windows/SDL_windows.h"
31 32
32 /* This function is where all the magic happens... */ 33 /* This function is where all the magic happens... */
33 SDL_bool 34 SDL_bool
34 SDL_AtomicTryLock(SDL_SpinLock *lock) 35 SDL_AtomicTryLock(SDL_SpinLock *lock)
35 { 36 {
36 #if defined(_MSC_VER) 37 #if SDL_ATOMIC_DISABLED
38 /* Terrible terrible damage */
39 static SDL_mutex *_spinlock_mutex;
40
41 if (!_spinlock_mutex) {
42 /* Race condition on first lock... */
43 _spinlock_mutex = SDL_CreateMutex();
44 }
45 SDL_mutexP(_spinlock_mutex);
46 if (*lock == 0) {
47 *lock = 1;
48 SDL_mutexV(_spinlock_mutex);
49 return SDL_TRUE;
50 } else {
51 SDL_mutexV(_spinlock_mutex);
52 return SDL_FALSE;
53 }
54
55 #elif defined(_MSC_VER)
37 SDL_COMPILE_TIME_ASSERT(locksize, sizeof(*lock) == sizeof(long)); 56 SDL_COMPILE_TIME_ASSERT(locksize, sizeof(*lock) == sizeof(long));
38 return (InterlockedExchange((long*)lock, 1) == 0); 57 return (InterlockedExchange((long*)lock, 1) == 0);
39 58
40 #elif defined(__MACOSX__) 59 #elif defined(__MACOSX__)
41 return OSAtomicCompareAndSwap32Barrier(0, 1, lock); 60 return OSAtomicCompareAndSwap32Barrier(0, 1, lock);