os_core/os_time.c

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/***********************************
* Operation System Kernel File
* function: os_time has a task queue which can queue tasks that wait for specific time out.
*           os_time also has a event queue which can queue events that has task pending on it.
*           os time tick must check task queues and event queues to see if any task time out
*
* File:   os_time.c
* Author: Book Chen
* Date: 2008.07.18
************************************
*/
#include "includes.h"

OS_EVENT *OsTimeEventList;
OS_TCB   *OsTimeDelayList;
OS_TIME_CONTROL OsTimeCtrl;

void OsTimeInit(void);
void OsTimeTickHandler(void);
void OsTimeDelayTaskPut(OS_TCB *pOsTcb);
void OsTimeDelay(INT16U Ticks);
void OsTimeEventListPut(OS_EVENT *pOsEvent);
INT8U OsTimeEventListDelete(OS_EVENT *pOsEvent);

void OsTimeInit(void){
    OsTimeDelayList=(OS_TCB *)0;
    OsTimeEventList=(OS_EVENT *)0;
    OsTimeCtrl.EntryNumber=0;    
    OsTimeCtrl.EventListNumber=0;    
    OsTimeCtrl.Time=0;
}
void OsTimeTickHandler(void){
    OS_TCB *pTcb,*pTcb2,*pTaskListHead;
    OS_EVENT *pEvent;
    
    OsTimeCtrl.Time++;
    if(OsTimeDelayList==(OS_TCB *)0) return;
    pTcb=OsTimeDelayList;
    while(pTcb!=(OS_TCB *)0){  // scan time delay task list       
        if(pTcb->TimeDelay!=0) pTcb->TimeDelay--;
        if(pTcb->TimeDelay==0){
            pTcb2=pTcb;
            if(pTcb2==OsTimeDelayList){
                if(OsTimeDelayList->Next==(OS_TCB *)0){
                    OsTimeDelayList=(OS_TCB *)0;
                    pTcb=(OS_TCB *)0; // no next task
                }
                else{
                    OsTimeDelayList=OsTimeDelayList->Next;
                    OsTimeDelayList->Prev=(OS_TCB *)0; 
                    pTcb=OsTimeDelayList; // next task is list head              
                }    
            }
            else if(pTcb2->Next==(OS_TCB *)0){
                pTcb2->Prev->Next=(OS_TCB *)0; 
                pTcb=(OS_TCB *)0; // no next task                         
            } 
            else{
                pTcb2->Prev->Next=pTcb2->Next;
                pTcb2->Next->Prev=pTcb2->Prev; 
                pTcb=pTcb2->Next;  // next task is next task                    
            }
            OsTimeCtrl.EntryNumber--;
            OsTaskReadyTaskPut(pTcb2); // task time out..become ready task again  
        }  
        else pTcb=pTcb->Next;
    }
    return;
    // scan event list to see if any pending task time out  
    pEvent=OsTimeEventList;  
    while(pEvent!=(OS_EVENT *)0){
        pTaskListHead=(OS_TCB *)pEvent->ListHead;
        pTcb=pTaskListHead;
        while(pTcb!=(OS_TCB *)0){
            if(pTcb->TimeDelay!=0) pTcb->TimeDelay--;
            if(pTcb->TimeDelay==0){
                pTcb2=pTcb;
                if(pTcb2==pTaskListHead){
                    if(pTaskListHead->Next==(OS_TCB *)0){
                        pEvent->ListHead=(INT32U *)0;
                        pTcb=(OS_TCB *)0; // no next task
                    }
                    else{
                        pEvent->ListHead=(INT32U *)pTaskListHead->Next;
                        pTaskListHead=pTaskListHead->Next;
                        pTaskListHead->Prev=(OS_TCB *)0; 
                        pTcb=pTaskListHead; // point to next TCB                     
                    }                
                }            
                else if(pTcb2->Next==(OS_TCB *)0){
                    pTcb2->Prev->Next=(OS_TCB *)0; 
                    pTcb=(OS_TCB *)0; // no next task                                        
                }
                else{
                    pTcb2->Prev->Next=pTcb2->Next;
                    pTcb2->Next->Prev=pTcb2->Prev; 
                    pTcb=pTcb2->Next;  // point to next TCB                                         
                }                
                pEvent->EntryNumber--;
                OsTaskReadyTaskPut(pTcb2); // task time out..become ready task again
            }
            else pTcb=pTcb->Next;     // point to next TCB  
        } 
        pEvent=pEvent->Next;   
    }
}
void OsTimeDelayTaskPut(OS_TCB *pOsTcb){
    pOsTcb->Next=(OS_TCB *)0;
    pOsTcb->Prev=(OS_TCB *)0;
    if(OsTimeCtrl.EntryNumber==0){        
        OsTimeDelayList=pOsTcb;
        OsTimeCtrl.EntryNumber=1;
    }
    else{
        pOsTcb->Next=OsTimeDelayList;
        OsTimeDelayList->Prev=pOsTcb;
        OsTimeDelayList=pOsTcb;
        OsTimeCtrl.EntryNumber++;
    }
}
void OsTimeDelay(INT16U Ticks){
    OS_TCB *pOsTcb;
    
    #if(OS_TIME_EVENT_ENABLE==0)
        return;
    #endif      
    OS_ENTER_CRITICAL();
    if(Ticks==0){
        OS_EXIT_CRITICAL();
        return;    
    }     
    pOsTcb=(OS_TCB *)OSTCBCur;
    pOsTcb->Status=OS_TASK_PENDING;
    pOsTcb->PendingType=OS_PENDING_TIME;
    pOsTcb->TimeDelay=Ticks;         
    OsTimeDelayTaskPut(pOsTcb);    
    OsSchedulerRunNext();  
    OS_EXIT_CRITICAL();
}
void OsTimeEventListPut(OS_EVENT *pOsEvent){
    pOsEvent->Next=(OS_EVENT *)0; // clear linking relation 
    pOsEvent->Prev=(OS_EVENT *)0; // clear linking relation
    if(OsTimeEventList==(OS_EVENT *)0){        
        OsTimeEventList=pOsEvent;
        OsTimeCtrl.EventListNumber=1;
    }
    else{
        pOsEvent->Next=OsTimeEventList;
        OsTimeEventList->Prev=pOsEvent;
        OsTimeEventList=pOsEvent;
        OsTimeCtrl.EventListNumber++;
    }
}
INT8U OsTimeEventListDelete(OS_EVENT *pOsEvent){
    OS_EVENT *pEvent;

    if(OsTimeEventList==(OS_EVENT *)0) return FALSE;
    pEvent=OsTimeEventList;
    while(pEvent!=(OS_EVENT *)0){        
        if(pOsEvent==pEvent){ // find event in list
            if(pEvent==OsTimeEventList){ // at list head
                if(OsTimeEventList->Next==(OS_EVENT *)0){
                    OsTimeEventList=(OS_EVENT *)0;                    
                }
                else{
                    OsTimeEventList=OsTimeEventList->Next;
                    OsTimeEventList->Prev=(OS_EVENT *)0;               
                }    
            }
            else if(pEvent->Next==(OS_EVENT *)0){ // at list tail
                pEvent->Prev->Next=(OS_EVENT *)0;                        
            }
            else{ // at list middle
                pEvent->Prev->Next=pEvent->Next;
                pEvent->Next->Prev=pEvent->Prev;                      
            }
            OsTimeCtrl.EventListNumber--;
            //OsEventFreeEventPut(pOsEvent); // no do it here 
            return TRUE;
        }  
        else pEvent=pEvent->Next;
    }    
    return FALSE;
}

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