From 5a079a2d114f96d4847d1ee305d5b7c16eeec50e Mon Sep 17 00:00:00 2001 From: 3gg <3gg@shellblade.net> Date: Sat, 27 Dec 2025 12:03:39 -0800 Subject: Initial commit --- contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c | 203 ++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c (limited to 'contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c') diff --git a/contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c b/contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c new file mode 100644 index 0000000..8e35c8a --- /dev/null +++ b/contrib/SDL-3.2.8/src/atomic/SDL_spinlock.c @@ -0,0 +1,203 @@ +/* + Simple DirectMedia Layer + Copyright (C) 1997-2025 Sam Lantinga + + 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(SDL_PLATFORM_WINDOWS) +#include "../core/windows/SDL_windows.h" +#endif + +#if !defined(HAVE_GCC_ATOMICS) && defined(SDL_PLATFORM_SOLARIS) +#include +#endif + +#if !defined(HAVE_GCC_ATOMICS) && defined(SDL_PLATFORM_RISCOS) +#include +#endif + +#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64)) +#include +#endif + +#ifdef PS2 +#include +#endif + +#if !defined(HAVE_GCC_ATOMICS) && defined(SDL_PLATFORM_MACOS) +#include +#endif + +/* *INDENT-OFF* */ // clang-format off +#if defined(__WATCOMC__) && defined(__386__) +SDL_COMPILE_TIME_ASSERT(locksize, 4==sizeof(SDL_SpinLock)); +extern __inline int _SDL_xchg_watcom(volatile int *a, int v); +#pragma aux _SDL_xchg_watcom = \ + "lock xchg [ecx], eax" \ + parm [ecx] [eax] \ + value [eax] \ + modify exact [eax]; +#endif // __WATCOMC__ && __386__ +/* *INDENT-ON* */ // clang-format on + +// This function is where all the magic happens... +bool SDL_TryLockSpinlock(SDL_SpinLock *lock) +{ +#if defined(HAVE_GCC_ATOMICS) || defined(HAVE_GCC_SYNC_LOCK_TEST_AND_SET) + return __sync_lock_test_and_set(lock, 1) == 0; + +#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64)) + return _InterlockedExchange_acq(lock, 1) == 0; + +#elif defined(_MSC_VER) + SDL_COMPILE_TIME_ASSERT(locksize, sizeof(*lock) == sizeof(long)); + return InterlockedExchange((long *)lock, 1) == 0; + +#elif defined(__WATCOMC__) && defined(__386__) + return _SDL_xchg_watcom(lock, 1) == 0; + +#elif defined(__GNUC__) && defined(__arm__) && \ + (defined(__ARM_ARCH_3__) || defined(__ARM_ARCH_3M__) || \ + defined(__ARM_ARCH_4__) || defined(__ARM_ARCH_4T__) || \ + defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5TE__) || \ + defined(__ARM_ARCH_5TEJ__)) + int result; + +#ifdef SDL_PLATFORM_RISCOS + if (__cpucap_have_rex()) { + __asm__ __volatile__( + "ldrex %0, [%2]\nteq %0, #0\nstrexeq %0, %1, [%2]" + : "=&r"(result) + : "r"(1), "r"(lock) + : "cc", "memory"); + return result == 0; + } +#endif + + __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(SDL_PLATFORM_MACOS) || defined(SDL_PLATFORM_IOS) || defined(SDL_PLATFORM_TVOS) + // Maybe used for PowerPC, but the Intel asm or gcc atomics are favored. + return OSAtomicCompareAndSwap32Barrier(0, 1, lock); + +#elif defined(SDL_PLATFORM_SOLARIS) && defined(_LP64) + // Used for Solaris with non-gcc compilers. + return ((int)atomic_cas_64((volatile uint64_t *)lock, 0, 1) == 0); + +#elif defined(SDL_PLATFORM_SOLARIS) && !defined(_LP64) + // Used for Solaris with non-gcc compilers. + return ((int)atomic_cas_32((volatile uint32_t *)lock, 0, 1) == 0); +#elif defined(PS2) + uint32_t oldintr; + bool res = false; + // disable interruption + oldintr = DIntr(); + + if (*lock == 0) { + *lock = 1; + res = true; + } + // enable interruption + if (oldintr) { + EIntr(); + } + return res; +#else + // 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 true; + } else { + SDL_UnlockMutex(_spinlock_mutex); + return false; + } +#endif +} + +void SDL_LockSpinlock(SDL_SpinLock *lock) +{ + int iterations = 0; + // FIXME: Should we have an eventual timeout? + while (!SDL_TryLockSpinlock(lock)) { + if (iterations < 32) { + iterations++; + SDL_CPUPauseInstruction(); + } else { + // !!! FIXME: this doesn't definitely give up the current timeslice, it does different things on various platforms. + SDL_Delay(0); + } + } +} + +void SDL_UnlockSpinlock(SDL_SpinLock *lock) +{ +#if defined(HAVE_GCC_ATOMICS) || defined(HAVE_GCC_SYNC_LOCK_TEST_AND_SET) + __sync_lock_release(lock); + +#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64)) + _InterlockedExchange_rel(lock, 0); + +#elif defined(_MSC_VER) + _ReadWriteBarrier(); + *lock = 0; + +#elif defined(__WATCOMC__) && defined(__386__) + SDL_CompilerBarrier(); + *lock = 0; + +#elif defined(SDL_PLATFORM_SOLARIS) + // Used for Solaris when not using gcc. + *lock = 0; + membar_producer(); + +#else + *lock = 0; +#endif +} -- cgit v1.2.3