void lock(int* semaphore)
{
    while (not compare_and_exchange(*semaphore, 0, 1))
    {
        futex(FUTEX_WAIT, semaphore, 1);
    }
}

void unlock(int* semaphore)
{
    if (compare_and_exchange(*semaphore, 1, 0))
    {
        futex(FUTEX_WAKE, semaphore, 1);
    }
}