mirror of https://github.com/encounter/SDL.git
136 lines
4.0 KiB
C
136 lines
4.0 KiB
C
/*
|
|
Simple DirectMedia Layer
|
|
Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
|
|
|
|
This software is provided 'as-is', without any express or implied
|
|
warranty. In no event will the authors be held liable for any damages
|
|
arising from the use of this software.
|
|
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it
|
|
freely, subject to the following restrictions:
|
|
|
|
1. The origin of this software must not be misrepresented; you must not
|
|
claim that you wrote the original software. If you use this software
|
|
in a product, an acknowledgment in the product documentation would be
|
|
appreciated but is not required.
|
|
2. Altered source versions must be plainly marked as such, and must not be
|
|
misrepresented as being the original software.
|
|
3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
#include "../SDL_internal.h"
|
|
|
|
#if defined(__WIN32__) || defined(__WINRT__)
|
|
#include "../core/windows/SDL_windows.h"
|
|
#endif
|
|
|
|
#include "SDL_atomic.h"
|
|
#include "SDL_mutex.h"
|
|
#include "SDL_timer.h"
|
|
|
|
#if !defined(HAVE_GCC_ATOMICS) && defined(__SOLARIS__)
|
|
#include <atomic.h>
|
|
#endif
|
|
|
|
/* This function is where all the magic happens... */
|
|
SDL_bool
|
|
SDL_AtomicTryLock(SDL_SpinLock *lock)
|
|
{
|
|
#if SDL_ATOMIC_DISABLED
|
|
/* Terrible terrible damage */
|
|
static SDL_mutex *_spinlock_mutex;
|
|
|
|
if (!_spinlock_mutex) {
|
|
/* Race condition on first lock... */
|
|
_spinlock_mutex = SDL_CreateMutex();
|
|
}
|
|
SDL_LockMutex(_spinlock_mutex);
|
|
if (*lock == 0) {
|
|
*lock = 1;
|
|
SDL_UnlockMutex(_spinlock_mutex);
|
|
return SDL_TRUE;
|
|
} else {
|
|
SDL_UnlockMutex(_spinlock_mutex);
|
|
return SDL_FALSE;
|
|
}
|
|
|
|
#elif defined(_MSC_VER)
|
|
SDL_COMPILE_TIME_ASSERT(locksize, sizeof(*lock) == sizeof(long));
|
|
return (InterlockedExchange((long*)lock, 1) == 0);
|
|
|
|
#elif HAVE_GCC_ATOMICS || HAVE_GCC_SYNC_LOCK_TEST_AND_SET
|
|
return (__sync_lock_test_and_set(lock, 1) == 0);
|
|
|
|
#elif defined(__GNUC__) && defined(__arm__) && \
|
|
(defined(__ARM_ARCH_4__) || defined(__ARM_ARCH_4T__) || \
|
|
defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5TE__) || \
|
|
defined(__ARM_ARCH_5TEJ__))
|
|
int result;
|
|
__asm__ __volatile__ (
|
|
"swp %0, %1, [%2]\n"
|
|
: "=&r,&r" (result) : "r,0" (1), "r,r" (lock) : "memory");
|
|
return (result == 0);
|
|
|
|
#elif defined(__GNUC__) && defined(__arm__)
|
|
int result;
|
|
__asm__ __volatile__ (
|
|
"ldrex %0, [%2]\nteq %0, #0\nstrexeq %0, %1, [%2]"
|
|
: "=&r" (result) : "r" (1), "r" (lock) : "cc", "memory");
|
|
return (result == 0);
|
|
|
|
#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
|
|
int result;
|
|
__asm__ __volatile__(
|
|
"lock ; xchgl %0, (%1)\n"
|
|
: "=r" (result) : "r" (lock), "0" (1) : "cc", "memory");
|
|
return (result == 0);
|
|
|
|
#elif defined(__MACOSX__) || defined(__IPHONEOS__)
|
|
/* Maybe used for PowerPC, but the Intel asm or gcc atomics are favored. */
|
|
return OSAtomicCompareAndSwap32Barrier(0, 1, lock);
|
|
|
|
#elif defined(__SOLARIS__) && defined(_LP64)
|
|
/* Used for Solaris with non-gcc compilers. */
|
|
return (SDL_bool) ((int) atomic_cas_64((volatile uint64_t*)lock, 0, 1) == 0);
|
|
|
|
#elif defined(__SOLARIS__) && !defined(_LP64)
|
|
/* Used for Solaris with non-gcc compilers. */
|
|
return (SDL_bool) ((int) atomic_cas_32((volatile uint32_t*)lock, 0, 1) == 0);
|
|
|
|
#else
|
|
#error Please implement for your platform.
|
|
return SDL_FALSE;
|
|
#endif
|
|
}
|
|
|
|
void
|
|
SDL_AtomicLock(SDL_SpinLock *lock)
|
|
{
|
|
/* FIXME: Should we have an eventual timeout? */
|
|
while (!SDL_AtomicTryLock(lock)) {
|
|
SDL_Delay(0);
|
|
}
|
|
}
|
|
|
|
void
|
|
SDL_AtomicUnlock(SDL_SpinLock *lock)
|
|
{
|
|
#if defined(_MSC_VER)
|
|
_ReadWriteBarrier();
|
|
*lock = 0;
|
|
|
|
#elif HAVE_GCC_ATOMICS || HAVE_GCC_SYNC_LOCK_TEST_AND_SET
|
|
__sync_lock_release(lock);
|
|
|
|
#elif defined(__SOLARIS__)
|
|
/* Used for Solaris when not using gcc. */
|
|
*lock = 0;
|
|
membar_producer();
|
|
|
|
#else
|
|
*lock = 0;
|
|
#endif
|
|
}
|
|
|
|
/* vi: set ts=4 sw=4 expandtab: */
|