os_core.c

基于ARM应用的源码

#if OS_TASK_STAT_EN
void OSStatInit (void)
{
    OSTimeDly(2);                                /* Synchronize with clock tick                        */
    OS_ENTER_CRITICAL();
    OSIdleCtr    = 0L;                           /* Clear idle counter                                 */
    OS_EXIT_CRITICAL();
    OSTimeDly(OS_TICKS_PER_SEC);                 /* Determine MAX. idle counter value for 1 second     */
    OS_ENTER_CRITICAL();
    OSIdleCtrMax = OSIdleCtr;                    /* Store maximum idle counter count in 1 second       */
    OSStatRdy    = TRUE;
    OS_EXIT_CRITICAL();
}
#endif

/*
*********************************************************************************************************
*                                              IDLE TASK
*
* Description: This task is internal to uC/OS-II and executes whenever no other higher priority tasks
*              executes because they are waiting for event(s) to occur.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/
void OSTaskIdle (void *pdata)
{
    pdata = pdata;									// 防止编译器警告
    for (;;) 
	{
        OS_ENTER_CRITICAL();
        OSIdleCtr++;
        OS_EXIT_CRITICAL();
    }
}

/*
*********************************************************************************************************
*                                            STATISTICS TASK
*
* Description: This task is internal to uC/OS-II and is used to compute some statistics about the
*              multitasking environment.  Specifically, OSTaskStat() computes the CPU usage.
*              CPU usage is determined by:
*
*                                          OSIdleCtr
*                 OSCPUUsage = 100 * (1 - ------------)     (units are in %)
*                                         OSIdleCtrMax
*
* Arguments  : pdata     this pointer is not used at this time.
*
* Returns    : none
*
* Notes      : 1) This task runs at a priority level higher than the idle task.  In fact, it runs at the
*                 next higher priority, OS_IDLE_PRIO-1.
*              2) You can disable this task by setting the configuration #define OS_TASK_STAT_EN to 0.
*              3) We delay for 5 seconds in the beginning to allow the system to reach steady state and
*                 have all other tasks created before we do statistics.  You MUST have at least a delay
*                 of 2 seconds to allow for the system to establish the maximum value for the idle 
*                 counter.
*********************************************************************************************************
*/

#if OS_TASK_STAT_EN
void OSTaskStat (void *pdata)
{
    INT32U run;
    INT8S  usage;
    
    
    pdata = pdata;												// 防止编译器警告
    while (OSStatRdy == FALSE) 
        OSTimeDly(2 * OS_TICKS_PER_SEC);						// 等待统计任务就绪

    for (;;) 
	{
        OS_ENTER_CRITICAL();
        OSIdleCtrRun = OSIdleCtr;                /* Obtain the of the idle counter for the past second */
        run          = OSIdleCtr;
        OSIdleCtr    = 0L;                       /* Reset the idle counter for the next second         */
        OS_EXIT_CRITICAL();
        if (OSIdleCtrMax > 0L) {
            usage = (INT8S)(100L - 100L * run / OSIdleCtrMax);
            if (usage > 100) {
                OSCPUUsage = 100;
            } else if (usage < 0) {
                OSCPUUsage =   0;
            } else {
                OSCPUUsage = usage;
            }
        } else {
            OSCPUUsage = 0;
        }
        OSTaskStatHook();                        /* Invoke user definable hook                         */
        OSTimeDly(OS_TICKS_PER_SEC);             /* Accumulate OSIdleCtr for the next second           */
    }
}
#endif

/*
*********************************************************************************************************
*                                            INITIALIZE TCB
*
* Description: This function is internal to uC/OS-II and is used to initialize a Task Control Block when
*              a task is created (see OSTaskCreate() and OSTaskCreateExt()).
*
* Arguments  : prio          is the priority of the task being created
*
*              ptos          is a pointer to the task's top-of-stack assuming that the CPU registers
*                            have been placed on the stack.  Note that the top-of-stack corresponds to a 
*                            'high' memory location is OS_STK_GROWTH is set to 1 and a 'low' memory
*                            location if OS_STK_GROWTH is set to 0.  Note that stack growth is CPU
*                            specific.
*
*              pbos          is a pointer to the bottom of stack.  A NULL pointer is passed if called by
*                            'OSTaskCreate()'.
*
*              id            is the task's ID (0..65535)
*
*              stk_size      is the size of the stack (in 'stack units').  If the stack units are INT8Us
*                            then, 'stk_size' contains the number of bytes for the stack.  If the stack
*                            units are INT32Us then, the stack contains '4 * stk_size' bytes.  The stack
*                            units are established by the #define constant OS_STK which is CPU
*                            specific.  'stk_size' is 0 if called by 'OSTaskCreate()'.
*
*              pext          is a pointer to a user supplied memory area that is used to extend the task
*                            control block.  This allows you to store the contents of floating-point
*                            registers, MMU registers or anything else you could find useful during a 
*                            context switch.  You can even assign a name to each task and store this name
*                            in this TCB extension.  A NULL pointer is passed if called by OSTaskCreate().
*
*              opt           options as passed to 'OSTaskCreateExt()' or, 
*                            0 if called from 'OSTaskCreate()'.
*
* Returns    : OS_NO_ERR         if the call was successful
*              OS_NO_MORE_TCB    if there are no more free TCBs to be allocated and thus, the task cannot
*                                be created.
*
* Note       : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

INT8U OSTCBInit (INT8U prio, OS_STK *ptos, OS_STK *pbos, INT16U id, INT16U stk_size, void *pext, INT16U opt)
{
    OS_TCB *ptcb;
	
	
    OS_ENTER_CRITICAL();
    ptcb = OSTCBFreeList;									// 从获取空闲 TCB 列表中获取一个空闲 TCB

    if (ptcb != (OS_TCB *)0)								// 获取成功
	{
        OSTCBFreeList        = ptcb->OSTCBNext;				// 刷新指向空闲 TCB 列表的指针
        OS_EXIT_CRITICAL();
        ptcb->OSTCBStkPtr    = ptos;						// 加载 TCB 栈指针
        ptcb->OSTCBPrio      = (INT8U)prio;					// 加载 TCB 任务优先级
        ptcb->OSTCBStat      = OS_STAT_RDY;					// 使任务就绪
        ptcb->OSTCBDly       = 0;							// 任务不被延迟
		
#if OS_TASK_CREATE_EXT_EN        
        ptcb->OSTCBExtPtr    = pext;						// 保存指针到 TCB 扩展块
        ptcb->OSTCBStkSize   = stk_size;					// 保存栈大小
        ptcb->OSTCBStkBottom = pbos;						// 保存指针到栈尾
        ptcb->OSTCBOpt       = opt;							// 保存任务选项
        ptcb->OSTCBId        = id;							// 保存任务 ID
#else
        pext                 = pext;						// 防止编译器警告
        stk_size             = stk_size;
        pbos                 = pbos;
        opt                  = opt;
        id                   = id;
#endif
		
#if OS_TASK_DEL_EN        
        ptcb->OSTCBDelReq    = OS_NO_ERR;
#endif
		
        ptcb->OSTCBY         = prio >> 3;					/* Pre-compute X, Y, BitX and BitY          */
        ptcb->OSTCBBitY      = OSMapTbl[ptcb->OSTCBY];
        ptcb->OSTCBX         = prio & 0x07;
        ptcb->OSTCBBitX      = OSMapTbl[ptcb->OSTCBX];
		
#if     OS_MBOX_EN || (OS_Q_EN && (OS_MAX_QS >= 2)) || OS_SEM_EN
        ptcb->OSTCBEventPtr  = (OS_EVENT *)0;				// 任务不悬挂在事件上
#endif
		
#if     OS_MBOX_EN || (OS_Q_EN && (OS_MAX_QS >= 2))
        ptcb->OSTCBMsg       = (void *)0;					// 没有接收到消息
#endif
		
        OS_ENTER_CRITICAL();
        OSTCBPrioTbl[prio]   = ptcb;
        ptcb->OSTCBNext      = OSTCBList;					// 链接到 TCB 链
        ptcb->OSTCBPrev      = (OS_TCB *)0;

        if (OSTCBList != (OS_TCB *)0) 
            OSTCBList->OSTCBPrev = ptcb;

        OSTCBList               = ptcb;
        OSRdyGrp               |= ptcb->OSTCBBitY;			// 运行就绪任务
        OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
    } 
	else 
	{
        OS_EXIT_CRITICAL();
        return (OS_NO_MORE_TCB);
    }
}

//--------------------------------------------------------------------------------------------
//	处理系统时钟 Tick
//	该函数将在 Ticker ISR 中被调用，但同时也可以由更高优先级的任务调用
//--------------------------------------------------------------------------------------------
void OSTimeTick (void)
{
    OS_TCB *ptcb;
	
    OSTimeTickHook();											// 调用用户定义的 HOOK

	// 遍历 TCB 列表中的所有 TCB
    ptcb = OSTCBList;											// 指向 TCB 列表中的第一个 TCB
    while (ptcb->OSTCBPrio != OS_IDLE_PRIO) 
	{
		//        OS_ENTER_CRITICAL();
        if (ptcb->OSTCBDly != 0) {								/* Delayed or waiting for event with TO     */
            if (--ptcb->OSTCBDly == 0) 							/* Decrement nbr of ticks to end of delay   */
			{
                if (!(ptcb->OSTCBStat & OS_STAT_SUSPEND))		// 如果任务未被挂起，则使就绪任务执行
				{
                    OSRdyGrp               |= ptcb->OSTCBBitY;
                    OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                } 
				else											// 如果任务被挂起...
                    ptcb->OSTCBDly = 1;							// 则等待 1 个 Tick 以防止在撤消挂起时任务丢失
            }
        }
        ptcb = ptcb->OSTCBNext;									// 指向下一个 TCB
		//        OS_EXIT_CRITICAL();
    }
	
	// 刷新 32 位 Tick 计数器
//	OS_ENTER_CRITICAL();
    OSTime++;
//	OS_EXIT_CRITICAL();
}

//--------------------------------------------------------------------------------------------
//	返回当前 uC/OS-II 操作系统的版本号
//
//	返回值：	返回值为实际的版本号乘以100 (如： uC/OS-II 2.00 返回值为 200)
//--------------------------------------------------------------------------------------------
INT16U OSVersion (void)
{
    return (OS_VERSION);
}