/* 
#include "pt-sem.h"

#define NUM_ITEMS 32
#define BUFSIZE 8

static struct pt_sem mutex, full, empty;

PT_THREAD(producer(struct pt *pt))
{
  static int produced;
  
  PT_BEGIN(pt);
  
  for(produced = 0; produced < NUM_ITEMS; ++produced) {
  
    PT_SEM_WAIT(pt, &full);
    
    PT_SEM_WAIT(pt, &mutex);
    add_to_buffer(produce_item());    
    PT_SEM_SIGNAL(pt, &mutex);
    
    PT_SEM_SIGNAL(pt, &empty);
  }

  PT_END(pt);
}

PT_THREAD(consumer(struct pt *pt))
{
  static int consumed;
  
  PT_BEGIN(pt);

  for(consumed = 0; consumed < NUM_ITEMS; ++consumed) {
    
    PT_SEM_WAIT(pt, &empty);
    
    PT_SEM_WAIT(pt, &mutex);    
    consume_item(get_from_buffer());    
    PT_SEM_SIGNAL(pt, &mutex);
    
    PT_SEM_SIGNAL(pt, &full);
  }

  PT_END(pt);
}

PT_THREAD(driver_thread(struct pt *pt))
{
  static struct pt pt_producer, pt_consumer;

  PT_BEGIN(pt);
  
  PT_SEM_INIT(&empty, 0);
  PT_SEM_INIT(&full, BUFSIZE);
  PT_SEM_INIT(&mutex, 1);

  PT_INIT(&pt_producer);
  PT_INIT(&pt_consumer);

  PT_WAIT_THREAD(pt, producer(&pt_producer) &
		     consumer(&pt_consumer));

  PT_END(pt);
} 
*/

#ifndef __PT_SEM_H__
#define __PT_SEM_H__

#include "pt.h"

struct pt_sem {
  unsigned int count;
};

//信号量
#define PT_SEM_INIT(s, c) (s)->count = c

//信号量等待 当信号量大于0 时继续,否则等待
#define PT_SEM_WAIT(pt, s)	\
  do {						\
    PT_WAIT_UNTIL(pt, (s)->count > 0);		\
    --(s)->count;				\
  } while(0)
 
  //写入信号量
#define PT_SEM_SIGNAL(pt, s) ++(s)->count

#endif /* __PT_SEM_H__ */

/** @} */
/** @} */