mdk-stage1/dietlibc/libpthread/pthread_spinlock.c


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#include <time.h>
#include <pthread.h>
#include "thread_internal.h"

static void __pthread_acquire(int * spinlock)
{
  int cnt = 0;
  struct timespec tm;

  while (__testandset(spinlock)) {
    if (cnt < MAX_SPIN_COUNT) {
      sched_yield();
      cnt++;
    } else {
      tm.tv_sec = 0;
      tm.tv_nsec = SPIN_SLEEP_DURATION;
      __libc_nanosleep(&tm, 0);
      cnt = 0;
    }
  }
}

void __pthread_lock(struct _pthread_fastlock * lock)
{
  __pthread_acquire(&lock->__spinlock);
}

int __pthread_trylock(struct _pthread_fastlock * lock)
{
  return __testandset(&lock->__spinlock);
}

int __pthread_unlock(struct _pthread_fastlock * lock)
{
  return (lock->__spinlock = 0);
}