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| /** |
| * Many similar implementations exist. See for example libwsbm |
| * or the linux kernel include/atomic.h |
| * |
| * No copyright claimed on this file. |
| * |
| */ |
| |
| #include "no_extern_c.h" |
| |
| #ifndef U_ATOMIC_H |
| #define U_ATOMIC_H |
| |
| #include <stdbool.h> |
| |
| /* Favor OS-provided implementations. |
| * |
| * Where no OS-provided implementation is available, fall back to |
| * locally coded assembly, compiler intrinsic or ultimately a |
| * mutex-based implementation. |
| */ |
| #if defined(__sun) |
| #define PIPE_ATOMIC_OS_SOLARIS |
| #elif defined(_MSC_VER) |
| #define PIPE_ATOMIC_MSVC_INTRINSIC |
| #elif defined(__GNUC__) |
| #define PIPE_ATOMIC_GCC_INTRINSIC |
| #else |
| #error "Unsupported platform" |
| #endif |
| |
| |
| /* Implementation using GCC-provided synchronization intrinsics |
| */ |
| #if defined(PIPE_ATOMIC_GCC_INTRINSIC) |
| |
| #define PIPE_ATOMIC "GCC Sync Intrinsics" |
| |
| #define p_atomic_set(_v, _i) (*(_v) = (_i)) |
| #define p_atomic_read(_v) (*(_v)) |
| #define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0) |
| #define p_atomic_inc(v) (void) __sync_add_and_fetch((v), 1) |
| #define p_atomic_dec(v) (void) __sync_sub_and_fetch((v), 1) |
| #define p_atomic_add(v, i) (void) __sync_add_and_fetch((v), (i)) |
| #define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1) |
| #define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1) |
| #define p_atomic_cmpxchg(v, old, _new) \ |
| __sync_val_compare_and_swap((v), (old), (_new)) |
| |
| #endif |
| |
| |
| |
| /* Unlocked version for single threaded environments, such as some |
| * windows kernel modules. |
| */ |
| #if defined(PIPE_ATOMIC_OS_UNLOCKED) |
| |
| #define PIPE_ATOMIC "Unlocked" |
| |
| #define p_atomic_set(_v, _i) (*(_v) = (_i)) |
| #define p_atomic_read(_v) (*(_v)) |
| #define p_atomic_dec_zero(_v) (p_atomic_dec_return(_v) == 0) |
| #define p_atomic_inc(_v) ((void) p_atomic_inc_return(_v)) |
| #define p_atomic_dec(_v) ((void) p_atomic_dec_return(_v)) |
| #define p_atomic_add(_v, _i) (*(_v) = *(_v) + (_i)) |
| #define p_atomic_inc_return(_v) (++(*(_v))) |
| #define p_atomic_dec_return(_v) (--(*(_v))) |
| #define p_atomic_cmpxchg(_v, _old, _new) (*(_v) == (_old) ? (*(_v) = (_new), (_old)) : *(_v)) |
| |
| #endif |
| |
| |
| #if defined(PIPE_ATOMIC_MSVC_INTRINSIC) |
| |
| #define PIPE_ATOMIC "MSVC Intrinsics" |
| |
| /* We use the Windows header's Interlocked*64 functions instead of the |
| * _Interlocked*64 intrinsics wherever we can, as support for the latter varies |
| * with target CPU, whereas Windows headers take care of all portability |
| * issues: using intrinsics where available, falling back to library |
| * implementations where not. |
| */ |
| #ifndef WIN32_LEAN_AND_MEAN |
| #define WIN32_LEAN_AND_MEAN 1 |
| #endif |
| #include <windows.h> |
| #include <intrin.h> |
| #include <assert.h> |
| |
| #if _MSC_VER < 1600 |
| |
| /* Implement _InterlockedCompareExchange8 in terms of _InterlockedCompareExchange16 */ |
| static __inline char |
| _InterlockedCompareExchange8(char volatile *destination8, char exchange8, char comparand8) |
| { |
| INT_PTR destinationAddr = (INT_PTR)destination8; |
| short volatile *destination16 = (short volatile *)(destinationAddr & ~1); |
| const short shift8 = (destinationAddr & 1) * 8; |
| const short mask8 = 0xff << shift8; |
| short initial16 = *destination16; |
| char initial8 = initial16 >> shift8; |
| while (initial8 == comparand8) { |
| /* initial *destination8 matches, so try exchange it while keeping the |
| * neighboring byte untouched */ |
| short exchange16 = (initial16 & ~mask8) | ((short)exchange8 << shift8); |
| short comparand16 = initial16; |
| short initial16 = _InterlockedCompareExchange16(destination16, exchange16, comparand16); |
| if (initial16 == comparand16) { |
| /* succeeded */ |
| return comparand8; |
| } |
| /* something changed, retry with the new initial value */ |
| initial8 = initial16 >> shift8; |
| } |
| return initial8; |
| } |
| |
| /* Implement _InterlockedExchangeAdd16 in terms of _InterlockedCompareExchange16 */ |
| static __inline short |
| _InterlockedExchangeAdd16(short volatile *addend, short value) |
| { |
| short initial = *addend; |
| short comparand; |
| do { |
| short exchange = initial + value; |
| comparand = initial; |
| /* if *addend==comparand then *addend=exchange, return original *addend */ |
| initial = _InterlockedCompareExchange16(addend, exchange, comparand); |
| } while(initial != comparand); |
| return comparand; |
| } |
| |
| /* Implement _InterlockedExchangeAdd8 in terms of _InterlockedCompareExchange8 */ |
| static __inline char |
| _InterlockedExchangeAdd8(char volatile *addend, char value) |
| { |
| char initial = *addend; |
| char comparand; |
| do { |
| char exchange = initial + value; |
| comparand = initial; |
| initial = _InterlockedCompareExchange8(addend, exchange, comparand); |
| } while(initial != comparand); |
| return comparand; |
| } |
| |
| #endif /* _MSC_VER < 1600 */ |
| |
| /* MSVC supports decltype keyword, but it's only supported on C++ and doesn't |
| * quite work here; and if a C++-only solution is worthwhile, then it would be |
| * better to use templates / function overloading, instead of decltype magic. |
| * Therefore, we rely on implicit casting to LONGLONG for the functions that return |
| */ |
| |
| #define p_atomic_set(_v, _i) (*(_v) = (_i)) |
| #define p_atomic_read(_v) (*(_v)) |
| |
| #define p_atomic_dec_zero(_v) \ |
| (p_atomic_dec_return(_v) == 0) |
| |
| #define p_atomic_inc(_v) \ |
| ((void) p_atomic_inc_return(_v)) |
| |
| #define p_atomic_inc_return(_v) (\ |
| sizeof *(_v) == sizeof(short) ? _InterlockedIncrement16((short *) (_v)) : \ |
| sizeof *(_v) == sizeof(long) ? _InterlockedIncrement ((long *) (_v)) : \ |
| sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_dec(_v) \ |
| ((void) p_atomic_dec_return(_v)) |
| |
| #define p_atomic_dec_return(_v) (\ |
| sizeof *(_v) == sizeof(short) ? _InterlockedDecrement16((short *) (_v)) : \ |
| sizeof *(_v) == sizeof(long) ? _InterlockedDecrement ((long *) (_v)) : \ |
| sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_add(_v, _i) (\ |
| sizeof *(_v) == sizeof(char) ? _InterlockedExchangeAdd8 ((char *) (_v), (_i)) : \ |
| sizeof *(_v) == sizeof(short) ? _InterlockedExchangeAdd16((short *) (_v), (_i)) : \ |
| sizeof *(_v) == sizeof(long) ? _InterlockedExchangeAdd ((long *) (_v), (_i)) : \ |
| sizeof *(_v) == sizeof(__int64) ? InterlockedExchangeAdd64((__int64 *)(_v), (_i)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_cmpxchg(_v, _old, _new) (\ |
| sizeof *(_v) == sizeof(char) ? _InterlockedCompareExchange8 ((char *) (_v), (char) (_new), (char) (_old)) : \ |
| sizeof *(_v) == sizeof(short) ? _InterlockedCompareExchange16((short *) (_v), (short) (_new), (short) (_old)) : \ |
| sizeof *(_v) == sizeof(long) ? _InterlockedCompareExchange ((long *) (_v), (long) (_new), (long) (_old)) : \ |
| sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #endif |
| |
| #if defined(PIPE_ATOMIC_OS_SOLARIS) |
| |
| #define PIPE_ATOMIC "Solaris OS atomic functions" |
| |
| #include <atomic.h> |
| #include <assert.h> |
| |
| #define p_atomic_set(_v, _i) (*(_v) = (_i)) |
| #define p_atomic_read(_v) (*(_v)) |
| |
| #define p_atomic_dec_zero(v) (\ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) == 0 : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_inc(v) (void) (\ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8 ((uint8_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_inc_return(v) ((__typeof(*v)) \ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8_nv ((uint8_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_dec(v) ((void) \ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8 ((uint8_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_dec_return(v) ((__typeof(*v)) \ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_add(v, i) ((void) \ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_add_8 ((uint8_t *)(v), (i)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_add_16((uint16_t *)(v), (i)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_add_32((uint32_t *)(v), (i)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_add_64((uint64_t *)(v), (i)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #define p_atomic_cmpxchg(v, old, _new) ((__typeof(*v)) \ |
| sizeof(*v) == sizeof(uint8_t) ? atomic_cas_8 ((uint8_t *)(v), (uint8_t )(old), (uint8_t )(_new)) : \ |
| sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \ |
| sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \ |
| sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \ |
| (assert(!"should not get here"), 0)) |
| |
| #endif |
| |
| #ifndef PIPE_ATOMIC |
| #error "No pipe_atomic implementation selected" |
| #endif |
| |
| |
| |
| #endif /* U_ATOMIC_H */ |