1. Class Cyg_Thread
   1. Class Cyg_HardwareThread
      1. // Static class to provide common func. Class Cyg_Scheduler
         1. Class_Scheduler_Implementation
            1. Class Scheduler_Base
            2. Class Cyg_Scheduler_SchedLock
            3. // Current running thread static Cyg_Thread * volatile current_thread[CYGNUM_KERNEL_CPU_MAX];
         2. static void unlock_inner(...);
         3. static void lock();
         4. static void unlock();
         5. static void reschedule();
         6. static unlock_reschedule();
         7. static unlock_simple();
         8. static void start();
         9. static void start_cpu();
         10. static Cyg_Scheduler scheduler;
      2. CYG_ADDRESS stack_base;
      3. cyg_uint32 stack_size;
      4. CYG_ADDRESS stack_ptr;
      5. cyg_thread_entry *entry_point;
      6. CYG_ADDRWORD entry_data;
      7. HAL_SaveRegisters *saved_context;
         1. //eg: hal/gx/ck/arch/v3_0/include/hal_arch.h typedef struct { ... ) HAL_SaveRegisters;
      8. static void thread_entry( Cyg_Thread *thread);
      9. void attach_stack( CYG_ADDRESS stack, cyg_uint32 stack_size);
      10. CYG_ADDRESS detach_stack();
   2. Class Cyg_SchedThread
      1. Class Cyg_SchedThread_Implementation
         1. void register_thread(Cyg_Thread *thread);
      2. Cyg_ThreadQueue *queue;
         1. class Cyg_ThreadQueue
            1. Class Cyg_ThreadQueue_Implementation
   3. Cyg_Thread(... );
      1. Cyg_Thread::Cyg_Thread( CYG_ADDRWORD sched_info, cyg_thread_entry *entry, CYG_ADDRWORD entry_data, char *name_arg, CYG_ADDRESS stack_base, cyg_ucount32 stack_size, int static_stack ): Cyg_HardwareThread(entry, entry_data, stack_size, stack_base), Cyg_SchedThread(this, sched_info), timer(this) { ... }
         1. add_to_list();
         2. Cyg_Scheduler.register_thread(this);
         3. init_context(this);
   4. static Cyg_Thread *thread_list;
   5. Cyg_Thread *list_next;
   6. void add_to_list( void);
   7. void remove_from_list( void);
   8. static Cyg_Thread *get_list_head();
   9. Cyg_Thread *get_list_next();
2. mlqueue/bitmap/lottery
   1. Cyg_Scheduler_Implementation
   2. Cyg_SchedThread_Implementation
   3. Cyg_ThreadQueue_Implementation
3. Timer Interrupt principle
   1. Cyg_RealTimeClock Cyg_RealTimeClock::rtc CYG_INIT_PRIORITY(CLOCK);
      1. Class Cyg_Clock
         1. Class Cyg_counter
            1. Cyg_Alarm_List alarm_list;
            2. Cyg_Counter::tick(count);
            3. {for(alarm_list) alarm->alarm();}
      2. Cyg_Interrupt interrupt;
         1. static cyg_uint32 isr(cyg_vector vector, CYG_ADDRWORD data);
            1. Almost do nothing, except call dsr
         2. static void dsr(cyg_vector vector, cyg_ucount32 count, CYG_ADDRWORD data);
            1. {rtc->tick(count);}
   2. Class Cyg_Thread : public Cyg_HardwareThread, public Cyg_SchedThread
      1. Cyg_ThreadTimer timer;
         1. Class Cyg_Alarm
         2. static void alarm( Cyg_Alarm *alarm, CYG_ADDRWORD data);
            1. {Cyg_Scheduler::unlock;}
            2. {Cyg_Scheduler::unlock_inner();}
            3. {CygInterrupt::call_pending_DSRs();}
            4. {HAL_THREAD_SWITCH_CONTEXT;}
4. externC void cyg_thread_create(...);