#define NPRIO 10

sem_t wait[NPRIO]={0,0....};
int nBlockedPrio[NPRIO]={0,0,...};
int nBlocked=0;
int pass = 0;
int sem=2;
sem_t sync=0;


int p(int prio, int value_p){
  int ret;

  P(m);
  if(sem==0){
    nBlocked++;
    nBlockedPrio[prio]++;
    V(m);
    P(wait[prio]);
    ret=pass;
    pass=value_p; 
    V(sync);
    return ret;
  }else{
    sem--;
    V(m);
    return 0;
  }
}


int v(int value_v){
  int ret;

  P(m);
  if(nBlocked){
    for(i=NPRIO-1; i>=0; i--){
      if (nBlockedPrio[i]){
        nBlockedPrio[i]--;
        nBlocked--;
        pass = value_v;
        V(wait[i]);
        P(sync);
        ret=pass;
        V(m);
        return ret;
      }
    }
  }else{
    sem++;
    V(m);
    return 0;
  }
}