A Small Multi-Tasking Operation System Using 8051: os

00001 /**************************************************
00002 * Tasking kernel file
00003 *
00004 * File:    os_core.c
00005 * Author:  Book Chen
00006 * 2008.08.08 
00007 ****************************************************
00008 */
00009 #include "..\inc\includes.h"
00010 #include "..\os_core\os_includes.h"
00011 
00012 INT8U data OSRunning=0;
00013 struct OS_CORE_CTRL OsCoreCtrl;
00014 void OsCorePowerOnInit(void) LargeReentrant;
00015 void OsCoreStart(void)       LargeReentrant; 
00016 void OsCoreScheduler(void)   LargeReentrant;
00017 
00018 void OsCorePowerOnInit() LargeReentrant{
00019     OsCoreCtrl.Status=0;   
00020     OsCoreCtrl.TaskSwitch=FALSE;
00021     OsCoreCtrl.TaskCswTimer=TASK_CSW_TIME;
00022     OSRunning=0;
00023 }
00024 void OsCoreStart() LargeReentrant{
00025     if((OSRunning==0)&&(OsTaskCtrl.TaskNum!=0)){ 
00026         OSRunning=1;                             // Set OS running flag 
00027         OsTaskCtrl.CurTaskId=0;                  // Set first task for running 
00028         OSPrioCur=OsTaskCtrl.CurTaskId;          // get current task id
00029         OSTCBCur=(INT16U)&TaskTable[OsTaskCtrl.CurTaskId]; // Get OS_TCB struct address
00030         OS_ENTER_CRITICAL();                     // Disable all interrupt 
00031         OsCpuLoadContext();                      // OS switch to first task
00032         OS_EXIT_CRITICAL();                      // This line will not execute...just for code symmetry
00033     }
00034 }
00035 void OsCoreScheduler(void) LargeReentrant{       // task level scheduler
00036     if(OsTaskCtrl.TaskNum>=2){                   // one task no need scheduler 
00037         OsCoreCtrl.TaskCswTimer=TASK_CSW_TIME;   // reset task switch timer
00038         if((OsTaskCtrl.CurTaskId+1)<OsTaskCtrl.TaskNum){
00039             OsTaskCtrl.CurTaskId++;
00040             OSPrioHighRdy=OsTaskCtrl.CurTaskId;
00041             OSTCBHighRdy=(INT16U)&TaskTable[OsTaskCtrl.CurTaskId];
00042         }
00043         else{
00044             OsTaskCtrl.CurTaskId=0;
00045             OSPrioHighRdy=OsTaskCtrl.CurTaskId;
00046             OSTCBHighRdy=(INT16U)&TaskTable[OsTaskCtrl.CurTaskId];
00047         }
00048         OsCoreCtrl.TaskSwitch=TRUE;              // set task switch flag true
00049     }
00050     if(OsCoreCtrl.TaskSwitch==TRUE){
00051         OsCoreCtrl.TaskSwitch=FALSE; 
00052         OsCpuContextSwitch();                    // task level context switch execution
00053     }
00054 }
00055 void OsCoreSchedulerIsr(void) LargeReentrant{    // interrupt level scheduler       
00056     if(OsTaskCtrl.TaskNum>=2){
00057         OsCoreCtrl.TaskCswTimer=TASK_CSW_TIME;
00058         if((OsTaskCtrl.CurTaskId+1)<OsTaskCtrl.TaskNum){
00059             OsTaskCtrl.CurTaskId++;
00060             OSPrioHighRdy=OsTaskCtrl.CurTaskId;
00061             OSTCBHighRdy=(INT16U)&TaskTable[OsTaskCtrl.CurTaskId];
00062         }
00063         else{
00064             OsTaskCtrl.CurTaskId=0;
00065             OSPrioHighRdy=OsTaskCtrl.CurTaskId;
00066             OSTCBHighRdy=(INT16U)&TaskTable[OsTaskCtrl.CurTaskId];
00067         }
00068         OsCoreCtrl.TaskSwitch=TRUE;             // set task switch flag true
00069     }
00070 }
00071