#ifndef AL_ATOMIC_H
#define AL_ATOMIC_H
#include "static_assert.h"
#include "bool.h"
#ifdef __GNUC__
/* This helps cast away the const-ness of a pointer without accidentally
* changing the pointer type. This is necessary due to Clang's inability to use
* atomic_load on a const _Atomic variable.
*/
#define CONST_CAST(T, V) __extension__({ \
const T _tmp = (V); \
(T)_tmp; \
})
#else
#define CONST_CAST(T, V) ((T)(V))
#endif
#ifdef __cplusplus
extern "C" {
#endif
/* Atomics using C11 */
#ifdef HAVE_C11_ATOMIC
#include <stdatomic.h>
#define almemory_order memory_order
#define almemory_order_relaxed memory_order_relaxed
#define almemory_order_consume memory_order_consume
#define almemory_order_acquire memory_order_acquire
#define almemory_order_release memory_order_release
#define almemory_order_acq_rel memory_order_acq_rel
#define almemory_order_seq_cst memory_order_seq_cst
#define ATOMIC(T) T _Atomic
#define ATOMIC_FLAG atomic_flag
#define ATOMIC_INIT atomic_init
#define ATOMIC_INIT_STATIC ATOMIC_VAR_INIT
/*#define ATOMIC_FLAG_INIT ATOMIC_FLAG_INIT*/
#define ATOMIC_LOAD atomic_load_explicit
#define ATOMIC_STORE atomic_store_explicit
#define ATOMIC_ADD atomic_fetch_add_explicit
#define ATOMIC_SUB atomic_fetch_sub_explicit
#define ATOMIC_EXCHANGE atomic_exchange_explicit
#define ATOMIC_COMPARE_EXCHANGE_STRONG atomic_compare_exchange_strong_explicit
#define ATOMIC_COMPARE_EXCHANGE_WEAK atomic_compare_exchange_weak_explicit
#define ATOMIC_FLAG_TEST_AND_SET atomic_flag_test_and_set_explicit
#define ATOMIC_FLAG_CLEAR atomic_flag_clear_explicit
#define ATOMIC_THREAD_FENCE atomic_thread_fence
/* Atomics using GCC intrinsics */
#elif defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) && !defined(__QNXNTO__)
enum almemory_order {
almemory_order_relaxed,
almemory_order_consume,
almemory_order_acquire,
almemory_order_release,
almemory_order_acq_rel,
almemory_order_seq_cst
};
#define ATOMIC(T) struct { T volatile value; }
#define ATOMIC_FLAG ATOMIC(int)
#define ATOMIC_INIT(_val, _newval) do { (_val)->value = (_newval); } while(0)
#define ATOMIC_INIT_STATIC(_newval) {(_newval)}
#define ATOMIC_FLAG_INIT ATOMIC_INIT_STATIC(0)
#define ATOMIC_LOAD(_val, _MO) __extension__({ \
__typeof((_val)->value) _r = (_val)->value; \
__asm__ __volatile__("" ::: "memory"); \
_r; \
})
#define ATOMIC_STORE(_val, _newval, _MO) do { \
__asm__ __volatile__("" ::: "memory"); \
(_val)->value = (_newval); \
} while(0)
#define ATOMIC_ADD(_val, _incr, _MO) __sync_fetch_and_add(&(_val)->value, (_incr))
#define ATOMIC_SUB(_val, _decr, _MO) __sync_fetch_and_sub(&(_val)->value, (_decr))
#define ATOMIC_EXCHANGE(_val, _newval, _MO) __extension__({ \
__asm__ __volatile__("" ::: "memory"); \
__sync_lock_test_and_set(&(_val)->value, (_newval)); \
})
#define ATOMIC_COMPARE_EXCHANGE_STRONG(_val, _oldval, _newval, _MO1, _MO2) __extension__({ \
__typeof(*(_oldval)) _o = *(_oldval); \
*(_oldval) = __sync_val_compare_and_swap(&(_val)->value, _o, (_newval)); \
*(_oldval) == _o; \
})
#define ATOMIC_FLAG_TEST_AND_SET(_val, _MO) __extension__({ \
__asm__ __volatile__("" ::: "memory"); \
__sync_lock_test_and_set(&(_val)->value, 1); \
})
#define ATOMIC_FLAG_CLEAR(_val, _MO) __extension__({ \
__sync_lock_release(&(_val)->value); \
__asm__ __volatile__("" ::: "memory"); \
})
#define ATOMIC_THREAD_FENCE(order) do { \
enum { must_be_constant = (order) }; \
const int _o = must_be_constant; \
if(_o > almemory_order_relaxed) \
__asm__ __volatile__("" ::: "memory"); \
} while(0)
/* Atomics using x86/x86-64 GCC inline assembly */
#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
#define WRAP_ADD(S, ret, dest, incr) __asm__ __volatile__( \
"lock; xadd"S" %0,(%1)" \
: "=r" (ret) \
: "r" (dest), "0" (incr) \
: "memory" \
)
#define WRAP_SUB(S, ret, dest, decr) __asm__ __volatile__( \
"lock; xadd"S" %0,(%1)" \
: "=r" (ret) \
: "r" (dest), "0" (-(decr)) \
: "memory" \
)
#define WRAP_XCHG(S, ret, dest, newval) __asm__ __volatile__( \
"lock; xchg"S" %0,(%1)" \
: "=r" (ret) \
: "r" (dest), "0" (newval) \
: "memory" \
)
#define WRAP_CMPXCHG(S, ret, dest, oldval, newval) __asm__ __volatile__( \
"lock; cmpxchg"S" %2,(%1)" \
: "=a" (ret) \
: "r" (dest), "r" (newval), "0" (oldval) \
: "memory" \
)
enum almemory_order {
almemory_order_relaxed,
almemory_order_consume,
almemory_order_acquire,
almemory_order_release,
almemory_order_acq_rel,
almemory_order_seq_cst
};
#define ATOMIC(T) struct { T volatile value; }
#define ATOMIC_INIT(_val, _newval) do { (_val)->value = (_newval); } while(0)
#define ATOMIC_INIT_STATIC(_newval) {(_newval)}
#define ATOMIC_LOAD(_val, _MO) __extension__({ \
__typeof((_val)->value) _r = (_val)->value; \
__asm__ __volatile__("" ::: "memory"); \
_r; \
})
#define ATOMIC_STORE(_val, _newval, _MO) do { \
__asm__ __volatile__("" ::: "memory"); \
(_val)->value = (_newval); \
} while(0)
#define ATOMIC_ADD(_val, _incr, _MO) __extension__({ \
static_assert(sizeof((_val)->value)==4 || sizeof((_val)->value)==8, "Unsupported size!"); \
__typeof((_val)->value) _r; \
if(sizeof((_val)->value) == 4) WRAP_ADD("l", _r, &(_val)->value, _incr); \
else if(sizeof((_val)->value) == 8) WRAP_ADD("q", _r, &(_val)->value, _incr); \
_r; \
})
#define ATOMIC_SUB(_val, _decr, _MO) __extension__({ \
static_assert(sizeof((_val)->value)==4 || sizeof((_val)->value)==8, "Unsupported size!"); \
__typeof((_val)->value) _r; \
if(sizeof((_val)->value) == 4) WRAP_SUB("l", _r, &(_val)->value, _decr); \
else if(sizeof((_val)->value) == 8) WRAP_SUB("q", _r, &(_val)->value, _decr); \
_r; \
})
#define ATOMIC_EXCHANGE(_val, _newval, _MO) __extension__({ \
__typeof((_val)->value) _r; \
if(sizeof((_val)->value) == 4) WRAP_XCHG("l", _r, &(_val)->value, (_newval)); \
else if(sizeof((_val)->value) == 8) WRAP_XCHG("q", _r, &(_val)->value, (_newval)); \
_r; \
})
#define ATOMIC_COMPARE_EXCHANGE_STRONG(_val, _oldval, _newval, _MO1, _MO2) __extension__({ \
__typeof(*(_oldval)) _old = *(_oldval); \
if(sizeof((_val)->value) == 4) WRAP_CMPXCHG("l", *(_oldval), &(_val)->value, _old, (_newval)); \
else if(sizeof((_val)->value) == 8) WRAP_CMPXCHG("q", *(_oldval), &(_val)->value, _old, (_newval)); \
*(_oldval) == _old; \
})
#define ATOMIC_EXCHANGE_PTR(_val, _newval, _MO) __extension__({ \
void *_r; \
if(sizeof(void*) == 4) WRAP_XCHG("l", _r, &(_val)->value, (_newval)); \
else if(sizeof(void*) == 8) WRAP_XCHG("q", _r, &(_val)->value, (_newval));\
_r; \
})
#define ATOMIC_COMPARE_EXCHANGE_PTR_STRONG(_val, _oldval, _newval, _MO1, _MO2) __extension__({ \
void *_old = *(_oldval); \
if(sizeof(void*) == 4) WRAP_CMPXCHG("l", *(_oldval), &(_val)->value, _old, (_newval)); \
else if(sizeof(void*) == 8) WRAP_CMPXCHG("q", *(_oldval), &(_val)->value, _old, (_newval)); \
*(_oldval) == _old; \
})
#define ATOMIC_THREAD_FENCE(order) do { \
enum { must_be_constant = (order) }; \
const int _o = must_be_constant; \
if(_o > almemory_order_relaxed) \
__asm__ __volatile__("" ::: "memory"); \
} while(0)
/* Atomics using Windows methods */
#elif defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
/* NOTE: This mess is *extremely* touchy. It lacks quite a bit of safety
* checking due to the lack of multi-statement expressions, typeof(), and C99
* compound literals. It is incapable of properly exchanging floats, which get
* casted to LONG/int, and could cast away potential warnings.
*
* Unfortunately, it's the only semi-safe way that doesn't rely on C99 (because
* MSVC).
*/
inline LONG AtomicAdd32(volatile LONG *dest, LONG incr)
{
return InterlockedExchangeAdd(dest, incr);
}
inline LONGLONG AtomicAdd64(volatile LONGLONG *dest, LONGLONG incr)
{
return InterlockedExchangeAdd64(dest, incr);
}
inline LONG AtomicSub32(volatile LONG *dest, LONG decr)
{
return InterlockedExchangeAdd(dest, -decr);
}
inline LONGLONG AtomicSub64(volatile LONGLONG *dest, LONGLONG decr)
{
return InterlockedExchangeAdd64(dest, -decr);
}
inline LONG AtomicSwap32(volatile LONG *dest, LONG newval)
{
return InterlockedExchange(dest, newval);
}
inline LONGLONG AtomicSwap64(volatile LONGLONG *dest, LONGLONG newval)
{
return InterlockedExchange64(dest, newval);
}
inline void *AtomicSwapPtr(void *volatile *dest, void *newval)
{
return InterlockedExchangePointer(dest, newval);
}
inline bool CompareAndSwap32(volatile LONG *dest, LONG newval, LONG *oldval)
{
LONG old = *oldval;
*oldval = InterlockedCompareExchange(dest, newval, *oldval);
return old == *oldval;
}
inline bool CompareAndSwap64(volatile LONGLONG *dest, LONGLONG newval, LONGLONG *oldval)
{
LONGLONG old = *oldval;
*oldval = InterlockedCompareExchange64(dest, newval, *oldval);
return old == *oldval;
}
inline bool CompareAndSwapPtr(void *volatile *dest, void *newval, void **oldval)
{
void *old = *oldval;
*oldval = InterlockedCompareExchangePointer(dest, newval, *oldval);
return old == *oldval;
}
#define WRAP_ADDSUB(T, _func, _ptr, _amnt) _func((T volatile*)(_ptr), (_amnt))
#define WRAP_XCHG(T, _func, _ptr, _newval) _func((T volatile*)(_ptr), (_newval))
#define WRAP_CMPXCHG(T, _func, _ptr, _newval, _oldval) _func((T volatile*)(_ptr), (_newval), (T*)(_oldval))
enum almemory_order {
almemory_order_relaxed,
almemory_order_consume,
almemory_order_acquire,
almemory_order_release,
almemory_order_acq_rel,
almemory_order_seq_cst
};
#define ATOMIC(T) struct { T volatile value; }
#define ATOMIC_INIT(_val, _newval) do { (_val)->value = (_newval); } while(0)
#define ATOMIC_INIT_STATIC(_newval) {(_newval)}
#define ATOMIC_LOAD(_val, _MO) ((_val)->value)
#define ATOMIC_STORE(_val, _newval, _MO) do { \
(_val)->value = (_newval); \
} while(0)
int _al_invalid_atomic_size(); /* not defined */
void *_al_invalid_atomic_ptr_size(); /* not defined */
#define ATOMIC_ADD(_val, _incr, _MO) \
((sizeof((_val)->value)==4) ? WRAP_ADDSUB(LONG, AtomicAdd32, &(_val)->value, (_incr)) : \
(sizeof((_val)->value)==8) ? WRAP_ADDSUB(LONGLONG, AtomicAdd64, &(_val)->value, (_incr)) : \
_al_invalid_atomic_size())
#define ATOMIC_SUB(_val, _decr, _MO) \
((sizeof((_val)->value)==4) ? WRAP_ADDSUB(LONG, AtomicSub32, &(_val)->value, (_decr)) : \
(sizeof((_val)->value)==8) ? WRAP_ADDSUB(LONGLONG, AtomicSub64, &(_val)->value, (_decr)) : \
_al_invalid_atomic_size())
#define ATOMIC_EXCHANGE(_val, _newval, _MO) \
((sizeof((_val)->value)==4) ? WRAP_XCHG(LONG, AtomicSwap32, &(_val)->value, (_newval)) : \
(sizeof((_val)->value)==8) ? WRAP_XCHG(LONGLONG, AtomicSwap64, &(_val)->value, (_newval)) : \
(LONG)_al_invalid_atomic_size())
#define ATOMIC_COMPARE_EXCHANGE_STRONG(_val, _oldval, _newval, _MO1, _MO2) \
((sizeof((_val)->value)==4) ? WRAP_CMPXCHG(LONG, CompareAndSwap32, &(_val)->value, (_newval), (_oldval)) : \
(sizeof((_val)->value)==8) ? WRAP_CMPXCHG(LONGLONG, CompareAndSwap64, &(_val)->value, (_newval), (_oldval)) : \
(bool)_al_invalid_atomic_size())
#define ATOMIC_EXCHANGE_PTR(_val, _newval, _MO) \
((sizeof((_val)->value)==sizeof(void*)) ? AtomicSwapPtr((void*volatile*)&(_val)->value, (_newval)) : \
_al_invalid_atomic_ptr_size())
#define ATOMIC_COMPARE_EXCHANGE_PTR_STRONG(_val, _oldval, _newval, _MO1, _MO2)\
((sizeof((_val)->value)==sizeof(void*)) ? CompareAndSwapPtr((void*volatile*)&(_val)->value, (_newval), (void**)(_oldval)) : \
(bool)_al_invalid_atomic_size())
#define ATOMIC_THREAD_FENCE(order) do { \
enum { must_be_constant = (order) }; \
const int _o = must_be_constant; \
if(_o > almemory_order_relaxed) \
_ReadWriteBarrier(); \
} while(0)
#else
#error "No atomic functions available on this platform!"
#define ATOMIC(T) T
#define ATOMIC_INIT(_val, _newval) ((void)0)
#define ATOMIC_INIT_STATIC(_newval) (0)
#define ATOMIC_LOAD(...) (0)
#define ATOMIC_STORE(...) ((void)0)
#define ATOMIC_ADD(...) (0)
#define ATOMIC_SUB(...) (0)
#define ATOMIC_EXCHANGE(...) (0)
#define ATOMIC_COMPARE_EXCHANGE_STRONG(...) (0)
#define ATOMIC_THREAD_FENCE(...) ((void)0)
#endif
/* If no PTR xchg variants are provided, the normal ones can handle it. */
#ifndef ATOMIC_EXCHANGE_PTR
#define ATOMIC_EXCHANGE_PTR ATOMIC_EXCHANGE
#define ATOMIC_COMPARE_EXCHANGE_PTR_STRONG ATOMIC_COMPARE_EXCHANGE_STRONG
#define ATOMIC_COMPARE_EXCHANGE_PTR_WEAK ATOMIC_COMPARE_EXCHANGE_WEAK
#endif
/* If no weak cmpxchg is provided (not all systems will have one), substitute a
* strong cmpxchg. */
#ifndef ATOMIC_COMPARE_EXCHANGE_WEAK
#define ATOMIC_COMPARE_EXCHANGE_WEAK ATOMIC_COMPARE_EXCHANGE_STRONG
#endif
#ifndef ATOMIC_COMPARE_EXCHANGE_PTR_WEAK
#define ATOMIC_COMPARE_EXCHANGE_PTR_WEAK ATOMIC_COMPARE_EXCHANGE_PTR_STRONG
#endif
/* If no ATOMIC_FLAG is defined, simulate one with an atomic int using exchange
* and store ops.
*/
#ifndef ATOMIC_FLAG
#define ATOMIC_FLAG ATOMIC(int)
#define ATOMIC_FLAG_INIT ATOMIC_INIT_STATIC(0)
#define ATOMIC_FLAG_TEST_AND_SET(_val, _MO) ATOMIC_EXCHANGE(_val, 1, _MO)
#define ATOMIC_FLAG_CLEAR(_val, _MO) ATOMIC_STORE(_val, 0, _MO)
#endif
#define ATOMIC_LOAD_SEQ(_val) ATOMIC_LOAD(_val, almemory_order_seq_cst)
#define ATOMIC_STORE_SEQ(_val, _newval) ATOMIC_STORE(_val, _newval, almemory_order_seq_cst)
#define ATOMIC_ADD_SEQ(_val, _incr) ATOMIC_ADD(_val, _incr, almemory_order_seq_cst)
#define ATOMIC_SUB_SEQ(_val, _decr) ATOMIC_SUB(_val, _decr, almemory_order_seq_cst)
#define ATOMIC_EXCHANGE_SEQ(_val, _newval) ATOMIC_EXCHANGE(_val, _newval, almemory_order_seq_cst)
#define ATOMIC_COMPARE_EXCHANGE_STRONG_SEQ(_val, _oldval, _newval) \
ATOMIC_COMPARE_EXCHANGE_STRONG(_val, _oldval, _newval, almemory_order_seq_cst, almemory_order_seq_cst)
#define ATOMIC_COMPARE_EXCHANGE_WEAK_SEQ(_val, _oldval, _newval) \
ATOMIC_COMPARE_EXCHANGE_WEAK(_val, _oldval, _newval, almemory_order_seq_cst, almemory_order_seq_cst)
#define ATOMIC_EXCHANGE_PTR_SEQ(_val, _newval) ATOMIC_EXCHANGE_PTR(_val, _newval, almemory_order_seq_cst)
#define ATOMIC_COMPARE_EXCHANGE_PTR_STRONG_SEQ(_val, _oldval, _newval) \
ATOMIC_COMPARE_EXCHANGE_PTR_STRONG(_val, _oldval, _newval, almemory_order_seq_cst, almemory_order_seq_cst)
#define ATOMIC_COMPARE_EXCHANGE_PTR_WEAK_SEQ(_val, _oldval, _newval) \
ATOMIC_COMPARE_EXCHANGE_PTR_WEAK(_val, _oldval, _newval, almemory_order_seq_cst, almemory_order_seq_cst)
typedef unsigned int uint;
typedef ATOMIC(uint) RefCount;
inline void InitRef(RefCount *ptr, uint value)
{ ATOMIC_INIT(ptr, value); }
inline uint ReadRef(RefCount *ptr)
{ return ATOMIC_LOAD_SEQ(ptr); }
inline uint IncrementRef(RefCount *ptr)
{ return ATOMIC_ADD_SEQ(ptr, 1)+1; }
inline uint DecrementRef(RefCount *ptr)
{ return ATOMIC_SUB_SEQ(ptr, 1)-1; }
/* WARNING: A livelock is theoretically possible if another thread keeps
* changing the head without giving this a chance to actually swap in the new
* one (practically impossible with this little code, but...).
*/
#define ATOMIC_REPLACE_HEAD(T, _head, _entry) do { \
T _first = ATOMIC_LOAD(_head, almemory_order_acquire); \
do { \
ATOMIC_STORE(&(_entry)->next, _first, almemory_order_relaxed); \
} while(ATOMIC_COMPARE_EXCHANGE_PTR_WEAK(_head, &_first, _entry, \
almemory_order_acq_rel, almemory_order_acquire) == 0); \
} while(0)
#ifdef __cplusplus
}
#endif
#endif /* AL_ATOMIC_H */