extern UINT16 nwk_event_loop( byte task_id, UINT16 events );

const pTaskEventHandlerFn tasksArr[] = {
 macEventLoop, nwk_event_loop,
  Hal_ProcessEvent,
#if defined( MT_TASK )
  MT_ProcessEvent,
#endif
  APS_event_loop, #if defined ( ZIGBEE_FRAGMENTATION )
  APSF_ProcessEvent,
#endif
  ZDApp_event_loop,
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
  ZDNwkMgr_event_loop,
#endif
#if defined( INTER_PAN )
  StubAPS_ProcessEvent,
#endif
  zcl_event_loop,
  zllTarget_event_loop,
  zllSampleLight_event_loop
};

请问标红的这些函数的实现在哪儿呢，跳转过去只有函数的声明。