newWait.c

/*
Suspend the current thread
on the condition.
*/
int green_cond_wait(green_cond_t* cond, green_mutex_t* mutex) {
    // block timer interrupt
    sigprocmask(SIG_BLOCK, &block, NULL);
    // suspend the running thread on condition
    green_t *susp = running;
    if (cond->end == NULL) {
       cond->front = cond->end = susp;
       return 0;
    }
    cond->end->next = susp;
    cond->end = susp;

    if(mutex != NULL) {
        // release the lock if we have a mutex
        mutex->taken = FALSE;
        // schedule suspended threads
        green_t* suspended = mutex->susp;
        while (suspended != NULL) {
            myEnQueue(suspended);
            suspended++;
            //suspended = mutex->susp;
        }
    }
    // schedule the next thread
    struct green_t* next = myDeQueue();
    running = next;
    swapcontext(susp->context, next->context);

    if(mutex != NULL) {
        // try to take the lock
        while(mutex->taken) {
            // bad luck, suspend

        }
        // take the lock
        mutex->taken = TRUE;
    }
    // unblock
    sigprocmask(SIG_UNBLOCK, &block, NULL);
    return 0;
}