/*Begin Function:_Sys_Init*****************************************************
Description : Initiate The Application Memory Page Allocation.
Input : Void.
Output : Void.
******************************************************************************/
void _Sys_Init(void) //The Paramount Process;Its PID is 0,forever.
{
u16 Count;
while(1)
{
DISABLE_ALL_INTS();
#if(ENABLE_SIGNAL==TRUE)
for(Count=1;Count<MAX_NUMBER_OF_TASKS+1;Count++) //Process The Signals Here.
_Sys_Signal_Handler(Count);
#endif
//The Code Below Sets The Task Sequence.
PCB_TASK_SEQ_PTR=0; //Reset The Process PTR.
for(Count=1;Count<MAX_NUMBER_OF_TASKS+2;Count++)
{ //From 1,For "Init" Do Not Count Here.
if(((PCB_PID_STATUS[Count]&OCCUPY)!=0)&&((PCB_PID_STATUS[Count]&SLEEP)==0)&&((PCB_PID_STATUS[Count]&ZOMBIE)==0))
{
PCB_REMAINING_TIME[Count]=PCB_TIM[Count];
PCB_TASK_SEQ[PCB_TASK_SEQ_PTR++]=Count; //Find Out The PIDs Occupied&Not Sleeping&Not Zombie And Create The Next Schedule Table.
}
}
PCB_TASK_SEQ[PCB_TASK_SEQ_PTR]=0; //The Last Must Be The Init process,Or The System Will Crash.Remember To Decrease The value By One,Or The System To Crash.
PCB_TASK_SEQ_PTR=0; //Reset The Process PTR.
ENABLE_ALL_INTS();
Sys_Switch_Now();
}
}
/* Begin Function:_Sys_Systick_Routine ****************************************
Description : The systick interrupt routine. No need to disable interrupts here,
because other interrupts may override it.
Input : None.
Output : None.
Return : None.
******************************************************************************/
void _Sys_Systick_Routine(void)
{
/* Always increase the tick count by one */
if(System_Status.Time.OS_Total_Ticks.Low_Bits==0xFFFFFFFF)
{
System_Status.Time.OS_Total_Ticks.Low_Bits=0;
System_Status.Time.OS_Total_Ticks.High_Bits++;
}
else
System_Status.Time.OS_Total_Ticks.Low_Bits++;
/* Process the signals again here, because the process may receive signals from ISR */
_Sys_Signal_Handler(Current_PID);
/* Process the timers here - see if any of them is expired */
_Sys_Timer_Handler();
/* Process the system process delay here - see if any of them is expired */
_Sys_Proc_Delay_Handler();
/* Do a scheduling here */
_Sys_Schedule_Trigger();
}
/* Begin Function:_Sys_Get_High_Ready *****************************************
Description : The function for deciding the highest priority task.
The routine has a very simple way to decide who's the final
task to run at last-it will set the "Current_PID" and the
"Current_Prio" correspondingly, and this only the two variables
will be used by the assembly function.
There's no need to disable interrupts here; because this is always
at the lowest priority.
Input : None.
Output : None.
Return : None.
******************************************************************************/
void _Sys_Get_High_Ready(void)
{
/* See if the scheduler is locked .If yes, then we cannot switch the tasks */
if(Scheduler_Locked==0)
{
/* The system is booting from "Init" process. We need do abandon the SP automatically
* saved by the "SYS_SAVE_SP" assembly function this time.
*/
if(System_Status.Kernel.Boot_Done==FALSE)
{
PCB_Cur_SP[0]=PCB[0].Info.Init_Stack_Ptr-PRESET_STACK_SIZE;
System_Status.Kernel.Boot_Done=TRUE;
}
/*If possible, decrease the remaining timeslice by 1.*/
if(PCB[Current_PID].Time.Lft_Tim>0)
{
PCB[Current_PID].Time.Lft_Tim-=1;
}
else
{
/* Refresh the timer */
PCB[Current_PID].Time.Lft_Tim=PCB[Current_PID].Time.Cur_Tim;
/* If the priority level still exists, then perform a normal context switch */
if(Prio_List[Current_Prio].Proc_Num!=0)
{
/* Do normal context switch first - See if the current process is running */
if(((struct PCB_Struct*)
(Prio_List[Current_Prio].Running_List.Next))
->Info.PID==Current_PID)
{
/* If the current process is running, then put it at the end of the queue */
Sys_List_Delete_Node(PCB[Current_PID].Head.Prev,PCB[Current_PID].Head.Next);
Sys_List_Insert_Node((struct List_Head*)&(PCB[Current_PID].Head),
Prio_List[Current_Prio].Running_List.Prev,
(struct List_Head*)&(Prio_List[Current_Prio].Running_List));
}
else
{
/* Do nothing - The current process is not running */
}
}
}
/* Now get the highest priority level's next process to run */
Current_Prio=((struct Prio_List_Struct*)(Prio_List_Head.Next))->Priority;
Current_PID=((struct PCB_Struct*)
(Prio_List[Current_Prio].Running_List.Next))
->Info.PID;
}
else
{
/* One of the scheduling action is pending due to scheduler lock. So
* after the scheduler unlocks, we will perform a schedule right away.
*/
Pend_Sched_Cnt++;
}
/* Refresh the system status,which is only for query*/
System_Status.Kernel.Proc_Running_Ptr=(struct List_Head*)(&(PCB[Current_PID].Head));
System_Status.Kernel.Cur_Prio_Ptr=(struct List_Head*)(&(Prio_List[PCB[Current_PID].Status.Priority].Head));
/* Process the signals here - The signal handlers will be directly called */
_Sys_Signal_Handler(Current_PID);
}