text: #ifndef _TIMER_H
  #define _TIMER_H
  
  // time_event
  typedef struct _time_event
  {
      int start_time;
      int duration;
      int expired_time;
  
      struct _time_event *prev;
      struct _time_event *next;
  
      char msg[0x100];
      void (*callback)(char*);
  } time_event;
  
  void timer_init();
  void timer_add(void (*callback)(char*), int sec, char* msg);
  
  void core_timer_enable(void);
  void core_timer_disable(void);
  void core_timer_handler(void);
  
  void each_timer_handler(void);
  
  void set_timeout(int sec);
  unsigned long get_current_time();
  
  
  #endif  /* _TIMER_H */