Initial Contribution
diff --git a/libcutils/atomic.c b/libcutils/atomic.c
new file mode 100644
index 0000000..65d7af0
--- /dev/null
+++ b/libcutils/atomic.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cutils/atomic.h>
+#ifdef HAVE_WIN32_THREADS
+#include <windows.h>
+#else
+#include <sched.h>
+#endif
+
+/*****************************************************************************/
+#if defined(HAVE_MACOSX_IPC)
+
+#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_inc(volatile int32_t* addr) {
+ return OSAtomicIncrement32Barrier((int32_t*)addr)-1;
+}
+
+int32_t android_atomic_dec(volatile int32_t* addr) {
+ return OSAtomicDecrement32Barrier((int32_t*)addr)+1;
+}
+
+int32_t android_atomic_add(int32_t value, volatile int32_t* addr) {
+ return OSAtomicAdd32Barrier(value, (int32_t*)addr)-value;
+}
+
+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;
+}
+
+int32_t android_atomic_or(int32_t value, volatile int32_t* addr) {
+ int32_t oldValue;
+ do {
+ oldValue = *addr;
+ } while (OSAtomicCompareAndSwap32Barrier(oldValue, oldValue|value, (int32_t*)addr) == 0);
+ 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) {
+ return OSAtomicCompareAndSwap32Barrier(oldvalue, newvalue, (int32_t*)addr) == 0;
+}
+
+#if defined(__ppc__) \
+ || defined(__PPC__) \
+ || defined(__powerpc__) \
+ || defined(__powerpc) \
+ || defined(__POWERPC__) \
+ || defined(_M_PPC) \
+ || defined(__PPC)
+#define NEED_QUASIATOMICS 1
+#else
+
+int android_quasiatomic_cmpxchg_64(int64_t oldvalue, int64_t newvalue,
+ volatile int64_t* addr) {
+ return OSAtomicCompareAndSwap64Barrier(oldvalue, newvalue,
+ (int64_t*)addr) == 0;
+}
+
+int64_t android_quasiatomic_swap_64(int64_t value, volatile int64_t* addr) {
+ int64_t oldValue;
+ do {
+ oldValue = *addr;
+ } while (android_quasiatomic_cmpxchg_64(oldValue, value, addr));
+ return oldValue;
+}
+
+int64_t android_quasiatomic_read_64(volatile int64_t* addr) {
+ return OSAtomicAdd64Barrier(0, addr);
+}
+
+#endif
+
+
+/*****************************************************************************/
+#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_inc(volatile int32_t* addr) {
+ int32_t oldValue;
+ do {
+ oldValue = *addr;
+ } while (android_atomic_cmpxchg(oldValue, oldValue+1, addr));
+ return oldValue;
+}
+
+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;
+}
+
+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));
+ return oldValue;
+}
+
+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));
+ return oldValue;
+}
+
+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));
+ 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) {
+ int xchg;
+ asm volatile
+ (
+ " lock; cmpxchg %%ecx, (%%edx);"
+ " setne %%al;"
+ " andl $1, %%eax"
+ : "=a" (xchg)
+ : "a" (oldvalue), "c" (newvalue), "d" (addr)
+ );
+ return xchg;
+}
+
+#define NEED_QUASIATOMICS 1
+
+/*****************************************************************************/
+#elif __arm__
+// Most of the implementation is in atomic-android-arm.s.
+
+// on the device, we implement the 64-bit atomic operations through
+// mutex locking. normally, this is bad because we must initialize
+// a pthread_mutex_t before being able to use it, and this means
+// having to do an initialization check on each function call, and
+// that's where really ugly things begin...
+//
+// BUT, as a special twist, we take advantage of the fact that in our
+// pthread library, a mutex is simply a volatile word whose value is always
+// initialized to 0. In other words, simply declaring a static mutex
+// object initializes it !
+//
+// another twist is that we use a small array of mutexes to dispatch
+// the contention locks from different memory addresses
+//
+
+#include <pthread.h>
+
+#define SWAP_LOCK_COUNT 32U
+static pthread_mutex_t _swap_locks[SWAP_LOCK_COUNT];
+
+#define SWAP_LOCK(addr) \
+ &_swap_locks[((unsigned)(void*)(addr) >> 3U) % SWAP_LOCK_COUNT]
+
+
+int64_t android_quasiatomic_swap_64(int64_t value, volatile int64_t* addr) {
+ int64_t oldValue;
+ pthread_mutex_t* lock = SWAP_LOCK(addr);
+
+ pthread_mutex_lock(lock);
+
+ oldValue = *addr;
+ *addr = value;
+
+ pthread_mutex_unlock(lock);
+ return oldValue;
+}
+
+int android_quasiatomic_cmpxchg_64(int64_t oldvalue, int64_t newvalue,
+ volatile int64_t* addr) {
+ int result;
+ pthread_mutex_t* lock = SWAP_LOCK(addr);
+
+ pthread_mutex_lock(lock);
+
+ if (*addr == oldvalue) {
+ *addr = newvalue;
+ result = 0;
+ } else {
+ result = 1;
+ }
+ pthread_mutex_unlock(lock);
+ return result;
+}
+
+int64_t android_quasiatomic_read_64(volatile int64_t* addr) {
+ int64_t result;
+ pthread_mutex_t* lock = SWAP_LOCK(addr);
+
+ pthread_mutex_lock(lock);
+ result = *addr;
+ pthread_mutex_unlock(lock);
+ return result;
+}
+
+#else
+
+#error "Unsupported atomic operations for this platform"
+
+#endif
+
+
+
+#if NEED_QUASIATOMICS
+
+/* Note that a spinlock is *not* a good idea in general
+ * since they can introduce subtle issues. For example,
+ * a real-time thread trying to acquire a spinlock already
+ * acquired by another thread will never yeld, making the
+ * CPU loop endlessly!
+ *
+ * However, this code is only used on the Linux simulator
+ * so it's probably ok for us.
+ *
+ * The alternative is to use a pthread mutex, but
+ * these must be initialized before being used, and
+ * then you have the problem of lazily initializing
+ * a mutex without any other synchronization primitive.
+ */
+
+/* global spinlock for all 64-bit quasiatomic operations */
+static int32_t quasiatomic_spinlock = 0;
+
+int android_quasiatomic_cmpxchg_64(int64_t oldvalue, int64_t newvalue,
+ volatile int64_t* addr) {
+ int result;
+
+ while (android_atomic_cmpxchg(0, 1, &quasiatomic_spinlock)) {
+#ifdef HAVE_WIN32_THREADS
+ Sleep(0);
+#else
+ sched_yield();
+#endif
+ }
+
+ if (*addr == oldvalue) {
+ *addr = newvalue;
+ result = 0;
+ } else {
+ result = 1;
+ }
+
+ android_atomic_swap(0, &quasiatomic_spinlock);
+
+ return result;
+}
+
+int64_t android_quasiatomic_read_64(volatile int64_t* addr) {
+ int64_t result;
+
+ while (android_atomic_cmpxchg(0, 1, &quasiatomic_spinlock)) {
+#ifdef HAVE_WIN32_THREADS
+ Sleep(0);
+#else
+ sched_yield();
+#endif
+ }
+
+ result = *addr;
+ android_atomic_swap(0, &quasiatomic_spinlock);
+
+ return result;
+}
+
+int64_t android_quasiatomic_swap_64(int64_t value, volatile int64_t* addr) {
+ int64_t result;
+
+ while (android_atomic_cmpxchg(0, 1, &quasiatomic_spinlock)) {
+#ifdef HAVE_WIN32_THREADS
+ Sleep(0);
+#else
+ sched_yield();
+#endif
+ }
+
+ result = *addr;
+ *addr = value;
+ android_atomic_swap(0, &quasiatomic_spinlock);
+
+ return result;
+}
+
+#endif