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Diffstat (limited to 'Source/external/SDL2/src/atomic/SDL_atomic.c')
| -rw-r--r-- | Source/external/SDL2/src/atomic/SDL_atomic.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/Source/external/SDL2/src/atomic/SDL_atomic.c b/Source/external/SDL2/src/atomic/SDL_atomic.c new file mode 100644 index 0000000..d0022cd --- /dev/null +++ b/Source/external/SDL2/src/atomic/SDL_atomic.c @@ -0,0 +1,304 @@ +/* + Simple DirectMedia Layer + Copyright (C) 1997-2018 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" + +#include "SDL_atomic.h" + +#if defined(_MSC_VER) && (_MSC_VER >= 1500) +#include <intrin.h> +#define HAVE_MSC_ATOMICS 1 +#endif + +#if defined(__MACOSX__) /* !!! FIXME: should we favor gcc atomics? */ +#include <libkern/OSAtomic.h> +#endif + +#if !defined(HAVE_GCC_ATOMICS) && defined(__SOLARIS__) +#include <atomic.h> +#endif + +/* The __atomic_load_n() intrinsic showed up in different times for different compilers. */ +#if defined(HAVE_GCC_ATOMICS) +# if defined(__clang__) +# if __has_builtin(__atomic_load_n) + /* !!! FIXME: this advertises as available in the NDK but uses an external symbol we don't have. + It might be in a later NDK or we might need an extra library? --ryan. */ +# if !defined(__ANDROID__) +# define HAVE_ATOMIC_LOAD_N 1 +# endif +# endif +# elif defined(__GNUC__) +# if (__GNUC__ >= 5) +# define HAVE_ATOMIC_LOAD_N 1 +# endif +# endif +#endif + +#if defined(__WATCOMC__) && defined(__386__) +SDL_COMPILE_TIME_ASSERT(intsize, 4==sizeof(int)); +#define HAVE_WATCOM_ATOMICS +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]; + +extern _inline unsigned char _SDL_cmpxchg_watcom(volatile int *a, int newval, int oldval); +#pragma aux _SDL_cmpxchg_watcom = \ + "lock cmpxchg [edx], ecx" \ + "setz al" \ + parm [edx] [ecx] [eax] \ + value [al] \ + modify exact [eax]; + +extern _inline int _SDL_xadd_watcom(volatile int *a, int v); +#pragma aux _SDL_xadd_watcom = \ + "lock xadd [ecx], eax" \ + parm [ecx] [eax] \ + value [eax] \ + modify exact [eax]; +#endif /* __WATCOMC__ && __386__ */ + +/* + If any of the operations are not provided then we must emulate some + of them. That means we need a nice implementation of spin locks + that avoids the "one big lock" problem. We use a vector of spin + locks and pick which one to use based on the address of the operand + of the function. + + To generate the index of the lock we first shift by 3 bits to get + rid on the zero bits that result from 32 and 64 bit allignment of + data. We then mask off all but 5 bits and use those 5 bits as an + index into the table. + + Picking the lock this way insures that accesses to the same data at + the same time will go to the same lock. OTOH, accesses to different + data have only a 1/32 chance of hitting the same lock. That should + pretty much eliminate the chances of several atomic operations on + different data from waiting on the same "big lock". If it isn't + then the table of locks can be expanded to a new size so long as + the new size is a power of two. + + Contributed by Bob Pendleton, bob@pendleton.com +*/ + +#if !defined(HAVE_MSC_ATOMICS) && !defined(HAVE_GCC_ATOMICS) && !defined(__MACOSX__) && !defined(__SOLARIS__) && !defined(HAVE_WATCOM_ATOMICS) +#define EMULATE_CAS 1 +#endif + +#if EMULATE_CAS +static SDL_SpinLock locks[32]; + +static SDL_INLINE void +enterLock(void *a) +{ + uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f); + + SDL_AtomicLock(&locks[index]); +} + +static SDL_INLINE void +leaveLock(void *a) +{ + uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f); + + SDL_AtomicUnlock(&locks[index]); +} +#endif + + +SDL_bool +SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval) +{ +#ifdef HAVE_MSC_ATOMICS + return (_InterlockedCompareExchange((long*)&a->value, (long)newval, (long)oldval) == (long)oldval); +#elif defined(HAVE_WATCOM_ATOMICS) + return (SDL_bool) _SDL_cmpxchg_watcom(&a->value, newval, oldval); +#elif defined(HAVE_GCC_ATOMICS) + return (SDL_bool) __sync_bool_compare_and_swap(&a->value, oldval, newval); +#elif defined(__MACOSX__) /* this is deprecated in 10.12 sdk; favor gcc atomics. */ + return (SDL_bool) OSAtomicCompareAndSwap32Barrier(oldval, newval, &a->value); +#elif defined(__SOLARIS__) && defined(_LP64) + return (SDL_bool) ((int) atomic_cas_64((volatile uint64_t*)&a->value, (uint64_t)oldval, (uint64_t)newval) == oldval); +#elif defined(__SOLARIS__) && !defined(_LP64) + return (SDL_bool) ((int) atomic_cas_32((volatile uint32_t*)&a->value, (uint32_t)oldval, (uint32_t)newval) == oldval); +#elif EMULATE_CAS + SDL_bool retval = SDL_FALSE; + + enterLock(a); + if (a->value == oldval) { + a->value = newval; + retval = SDL_TRUE; + } + leaveLock(a); + + return retval; +#else + #error Please define your platform. +#endif +} + +SDL_bool +SDL_AtomicCASPtr(void **a, void *oldval, void *newval) +{ +#if defined(HAVE_MSC_ATOMICS) && (_M_IX86) + return (_InterlockedCompareExchange((long*)a, (long)newval, (long)oldval) == (long)oldval); +#elif defined(HAVE_MSC_ATOMICS) && (!_M_IX86) + return (_InterlockedCompareExchangePointer(a, newval, oldval) == oldval); +#elif defined(HAVE_WATCOM_ATOMICS) + return (SDL_bool) _SDL_cmpxchg_watcom((int *)a, (long)newval, (long)oldval); +#elif defined(HAVE_GCC_ATOMICS) + return __sync_bool_compare_and_swap(a, oldval, newval); +#elif defined(__MACOSX__) && defined(__LP64__) /* this is deprecated in 10.12 sdk; favor gcc atomics. */ + return (SDL_bool) OSAtomicCompareAndSwap64Barrier((int64_t)oldval, (int64_t)newval, (int64_t*) a); +#elif defined(__MACOSX__) && !defined(__LP64__) /* this is deprecated in 10.12 sdk; favor gcc atomics. */ + return (SDL_bool) OSAtomicCompareAndSwap32Barrier((int32_t)oldval, (int32_t)newval, (int32_t*) a); +#elif defined(__SOLARIS__) + return (SDL_bool) (atomic_cas_ptr(a, oldval, newval) == oldval); +#elif EMULATE_CAS + SDL_bool retval = SDL_FALSE; + + enterLock(a); + if (*a == oldval) { + *a = newval; + retval = SDL_TRUE; + } + leaveLock(a); + + return retval; +#else + #error Please define your platform. +#endif +} + +int +SDL_AtomicSet(SDL_atomic_t *a, int v) +{ +#ifdef HAVE_MSC_ATOMICS + return _InterlockedExchange((long*)&a->value, v); +#elif defined(HAVE_WATCOM_ATOMICS) + return _SDL_xchg_watcom(&a->value, v); +#elif defined(HAVE_GCC_ATOMICS) + return __sync_lock_test_and_set(&a->value, v); +#elif defined(__SOLARIS__) && defined(_LP64) + return (int) atomic_swap_64((volatile uint64_t*)&a->value, (uint64_t)v); +#elif defined(__SOLARIS__) && !defined(_LP64) + return (int) atomic_swap_32((volatile uint32_t*)&a->value, (uint32_t)v); +#else + int value; + do { + value = a->value; + } while (!SDL_AtomicCAS(a, value, v)); + return value; +#endif +} + +void* +SDL_AtomicSetPtr(void **a, void *v) +{ +#if defined(HAVE_MSC_ATOMICS) && (_M_IX86) + return (void *) _InterlockedExchange((long *)a, (long) v); +#elif defined(HAVE_MSC_ATOMICS) && (!_M_IX86) + return _InterlockedExchangePointer(a, v); +#elif defined(HAVE_WATCOM_ATOMICS) + return (void *) _SDL_xchg_watcom((int *)a, (long)v); +#elif defined(HAVE_GCC_ATOMICS) + return __sync_lock_test_and_set(a, v); +#elif defined(__SOLARIS__) + return atomic_swap_ptr(a, v); +#else + void *value; + do { + value = *a; + } while (!SDL_AtomicCASPtr(a, value, v)); + return value; +#endif +} + +int +SDL_AtomicAdd(SDL_atomic_t *a, int v) +{ +#ifdef HAVE_MSC_ATOMICS + return _InterlockedExchangeAdd((long*)&a->value, v); +#elif defined(HAVE_WATCOM_ATOMICS) + return _SDL_xadd_watcom(&a->value, v); +#elif defined(HAVE_GCC_ATOMICS) + return __sync_fetch_and_add(&a->value, v); +#elif defined(__SOLARIS__) + int pv = a->value; + membar_consumer(); +#if defined(_LP64) + atomic_add_64((volatile uint64_t*)&a->value, v); +#elif !defined(_LP64) + atomic_add_32((volatile uint32_t*)&a->value, v); +#endif + return pv; +#else + int value; + do { + value = a->value; + } while (!SDL_AtomicCAS(a, value, (value + v))); + return value; +#endif +} + +int +SDL_AtomicGet(SDL_atomic_t *a) +{ +#ifdef HAVE_ATOMIC_LOAD_N + return __atomic_load_n(&a->value, __ATOMIC_SEQ_CST); +#else + int value; + do { + value = a->value; + } while (!SDL_AtomicCAS(a, value, value)); + return value; +#endif +} + +void * +SDL_AtomicGetPtr(void **a) +{ +#ifdef HAVE_ATOMIC_LOAD_N + return __atomic_load_n(a, __ATOMIC_SEQ_CST); +#else + void *value; + do { + value = *a; + } while (!SDL_AtomicCASPtr(a, value, value)); + return value; +#endif +} + +void +SDL_MemoryBarrierReleaseFunction(void) +{ + SDL_MemoryBarrierRelease(); +} + +void +SDL_MemoryBarrierAcquireFunction(void) +{ + SDL_MemoryBarrierAcquire(); +} + +/* vi: set ts=4 sw=4 expandtab: */ |