--- /dev/null
+#include <stdio.h>
+#include "cds_threads.h"
+#include "cds_atomic.h"
+
+#include "librace.h"
+
+#define RW_LOCK_BIAS 0x00100000
+#define WRITE_LOCK_CMP RW_LOCK_BIAS
+
+/** Example implementation of linux rw lock along with 2 thread test
+ * driver... */
+
+typedef union {
+ atomic_int lock;
+} rwlock_t;
+
+static inline int read_can_lock(rwlock_t *lock)
+{
+ return atomic_load_explicit(&lock->lock, memory_order_relaxed) > 0;
+}
+
+static inline int write_can_lock(rwlock_t *lock)
+{
+ return atomic_load_explicit(&lock->lock, memory_order_relaxed) == RW_LOCK_BIAS;
+}
+
+static inline void read_lock(rwlock_t *rw)
+{
+ int priorvalue = atomic_fetch_sub_explicit(&rw->lock, 1, memory_order_acquire);
+ while (priorvalue <= 0) {
+ atomic_fetch_add_explicit(&rw->lock, 1, memory_order_relaxed);
+ while (atomic_load_explicit(&rw->lock, memory_order_relaxed) <= 0) {
+ thrd_yield();
+ }
+ priorvalue = atomic_fetch_sub_explicit(&rw->lock, 1, memory_order_relaxed);
+ }
+}
+
+static inline void write_lock(rwlock_t *rw)
+{
+ int priorvalue = atomic_fetch_sub_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_acquire);
+ while (priorvalue != RW_LOCK_BIAS) {
+ atomic_fetch_add_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_relaxed);
+ while (atomic_load_explicit(&rw->lock, memory_order_relaxed) != RW_LOCK_BIAS) {
+ thrd_yield();
+ }
+ priorvalue = atomic_fetch_sub_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_relaxed);
+ }
+}
+
+static inline int read_trylock(rwlock_t *rw)
+{
+ int priorvalue = atomic_fetch_sub_explicit(&rw->lock, 1, memory_order_acquire);
+ if (priorvalue > 0)
+ return 1;
+
+ atomic_fetch_add_explicit(&rw->lock, 1, memory_order_relaxed);
+ return 0;
+}
+
+static inline int write_trylock(rwlock_t *rw)
+{
+ int priorvalue = atomic_fetch_sub_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_acquire);
+ if (priorvalue == RW_LOCK_BIAS)
+ return 1;
+
+ atomic_fetch_add_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_relaxed);
+ return 0;
+}
+
+static inline void read_unlock(rwlock_t *rw)
+{
+ atomic_fetch_add_explicit(&rw->lock, 1, memory_order_release);
+}
+
+static inline void write_unlock(rwlock_t *rw)
+{
+ atomic_fetch_add_explicit(&rw->lock, RW_LOCK_BIAS, memory_order_release);
+}
+
+rwlock_t mylock;
+int shareddata;
+
+void a()
+{
+// std::this_thread::sleep_for(std::chrono::milliseconds(10));
+ int i, rs;
+ for(i = 0; i < 2; i++) {
+ if ((i % 2) == 0) {
+ read_lock(&mylock);
+ rs = load_32(&shareddata);
+ read_unlock(&mylock);
+ } else {
+ write_lock(&mylock);
+ std::this_thread::yield();
+ store_32(&shareddata,(unsigned int)i);
+ write_unlock(&mylock);
+ }
+ }
+}
+
+int user_main(int argc, char **argv)
+{
+ //thrd_t t1, t2;
+ atomic_init(&mylock.lock, RW_LOCK_BIAS);
+
+ std::thread t1(a);
+ std::thread t2(a);
+ //thrd_create(&t1, (thrd_start_t)&a, NULL);
+ //thrd_create(&t2, (thrd_start_t)&a, NULL);
+
+ t1.join();
+ t2.join();
+ //thrd_join(t1);
+ //thrd_join(t2);
+
+ return 0;
+}