diff options
Diffstat (limited to 'libcutils/atomic.c')
| -rw-r--r-- | libcutils/atomic.c | 142 |
1 files changed, 87 insertions, 55 deletions
diff --git a/libcutils/atomic.c b/libcutils/atomic.c index d8189061..4cefa6b9 100644 --- a/libcutils/atomic.c +++ b/libcutils/atomic.c @@ -27,11 +27,25 @@ #include <libkern/OSAtomic.h> -void android_atomic_write(int32_t value, volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (OSAtomicCompareAndSwap32Barrier(oldValue, value, (int32_t*)addr) == 0); +int32_t android_atomic_acquire_load(volatile int32_t* addr) { + int32_t value = *addr; + OSMemoryBarrier(); + return value; +} + +int32_t android_atomic_release_load(volatile int32_t* addr) { + OSMemoryBarrier(); + return *addr; +} + +void android_atomic_acquire_store(int32_t value, volatile int32_t* addr) { + *addr = value; + OSMemoryBarrier(); +} + +void android_atomic_release_store(int32_t value, volatile int32_t* addr) { + OSMemoryBarrier(); + *addr = value; } int32_t android_atomic_inc(volatile int32_t* addr) { @@ -47,74 +61,81 @@ int32_t android_atomic_add(int32_t value, volatile int32_t* addr) { } int32_t android_atomic_and(int32_t value, volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (OSAtomicCompareAndSwap32Barrier(oldValue, oldValue&value, (int32_t*)addr) == 0); - return oldValue; + return OSAtomicAnd32OrigBarrier(value, (int32_t*)addr); } int32_t android_atomic_or(int32_t value, volatile int32_t* addr) { + return OSAtomicOr32OrigBarrier(value, (int32_t*)addr); +} + +int32_t android_atomic_acquire_swap(int32_t value, volatile int32_t* addr) { int32_t oldValue; do { oldValue = *addr; - } while (OSAtomicCompareAndSwap32Barrier(oldValue, oldValue|value, (int32_t*)addr) == 0); + } while (android_atomic_acquire_cas(oldValue, value, addr)); return oldValue; } -int32_t android_atomic_swap(int32_t value, volatile int32_t* addr) { +int32_t android_atomic_release_swap(int32_t value, volatile int32_t* addr) { int32_t oldValue; do { oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, value, addr)); + } while (android_atomic_release_cas(oldValue, value, addr)); return oldValue; } -int android_atomic_cmpxchg(int32_t oldvalue, int32_t newvalue, volatile int32_t* addr) { +int android_atomic_release_cas(int32_t oldvalue, int32_t newvalue, volatile int32_t* addr) { /* OS X CAS returns zero on failure; invert to return zero on success */ return OSAtomicCompareAndSwap32Barrier(oldvalue, newvalue, (int32_t*)addr) == 0; } -int android_atomic_acquire_cmpxchg(int32_t oldvalue, int32_t newvalue, +int android_atomic_acquire_cas(int32_t oldvalue, int32_t newvalue, volatile int32_t* addr) { int result = (OSAtomicCompareAndSwap32(oldvalue, newvalue, (int32_t*)addr) == 0); - if (!result) { + if (result == 0) { /* success, perform barrier */ OSMemoryBarrier(); } + return result; } /*****************************************************************************/ #elif defined(__i386__) || defined(__x86_64__) -void android_atomic_write(int32_t value, volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, value, addr)); +int32_t android_atomic_acquire_load(volatile int32_t* addr) { + int32_t value = *addr; + ANDROID_MEMBAR_FULL(); + return value; +} + +int32_t android_atomic_release_load(volatile int32_t* addr) { + ANDROID_MEMBAR_FULL(); + return *addr; +} + +void android_atomic_acquire_store(int32_t value, volatile int32_t* addr) { + *addr = value; + ANDROID_MEMBAR_FULL(); +} + +void android_atomic_release_store(int32_t value, volatile int32_t* addr) { + ANDROID_MEMBAR_FULL(); + *addr = value; } int32_t android_atomic_inc(volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, oldValue+1, addr)); - return oldValue; + return android_atomic_add(1, addr); } int32_t android_atomic_dec(volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, oldValue-1, addr)); - return oldValue; + return android_atomic_add(-1, addr); } int32_t android_atomic_add(int32_t value, volatile int32_t* addr) { int32_t oldValue; do { oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, oldValue+value, addr)); + } while (android_atomic_release_cas(oldValue, oldValue+value, addr)); return oldValue; } @@ -122,7 +143,7 @@ int32_t android_atomic_and(int32_t value, volatile int32_t* addr) { int32_t oldValue; do { oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, oldValue&value, addr)); + } while (android_atomic_release_cas(oldValue, oldValue&value, addr)); return oldValue; } @@ -130,20 +151,13 @@ int32_t android_atomic_or(int32_t value, volatile int32_t* addr) { int32_t oldValue; do { oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, oldValue|value, addr)); + } while (android_atomic_release_cas(oldValue, oldValue|value, addr)); return oldValue; } -int32_t android_atomic_swap(int32_t value, volatile int32_t* addr) { - int32_t oldValue; - do { - oldValue = *addr; - } while (android_atomic_cmpxchg(oldValue, value, addr)); - return oldValue; -} - -int android_atomic_cmpxchg(int32_t oldvalue, int32_t newvalue, volatile int32_t* addr) { - android_membar_full(); +/* returns 0 on successful swap */ +static inline int cas(int32_t oldvalue, int32_t newvalue, + volatile int32_t* addr) { int xchg; asm volatile ( @@ -156,18 +170,36 @@ int android_atomic_cmpxchg(int32_t oldvalue, int32_t newvalue, volatile int32_t* return xchg; } -int android_atomic_acquire_cmpxchg(int32_t oldvalue, int32_t newvalue, +int32_t android_atomic_acquire_swap(int32_t value, volatile int32_t* addr) { + int32_t oldValue; + do { + oldValue = *addr; + } while (cas(oldValue, value, addr)); + ANDROID_MEMBAR_FULL(); + return oldValue; +} + +int32_t android_atomic_release_swap(int32_t value, volatile int32_t* addr) { + ANDROID_MEMBAR_FULL(); + int32_t oldValue; + do { + oldValue = *addr; + } while (cas(oldValue, value, addr)); + return oldValue; +} + +int android_atomic_acquire_cas(int32_t oldvalue, int32_t newvalue, + volatile int32_t* addr) { + int xchg = cas(oldvalue, newvalue, addr); + if (xchg == 0) + ANDROID_MEMBAR_FULL(); + return xchg; +} + +int android_atomic_release_cas(int32_t oldvalue, int32_t newvalue, volatile int32_t* addr) { - int xchg; - asm volatile - ( - " lock; cmpxchg %%ecx, (%%edx);" - " setne %%al;" - " andl $1, %%eax" - : "=a" (xchg) - : "a" (oldvalue), "c" (newvalue), "d" (addr) - ); - android_membar_full(); + ANDROID_MEMBAR_FULL(); + int xchg = cas(oldvalue, newvalue, addr); return xchg; } |