os_task.c

嵌入式实时操作系统uCOS-II源码

/*$PAGE*/
/*
*********************************************************************************************************
*                                             STACK CHECKING
*
* Description: This function is called to check the amount of free memory left on the specified task's
*              stack.
*
* Arguments  : prio          is the task priority
*
*              p_stk_data    is a pointer to a data structure of type OS_STK_DATA.
*
* Returns    : OS_NO_ERR           upon success
*              OS_PRIO_INVALID     if the priority you specify is higher that the maximum allowed
*                                  (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
*              OS_TASK_NOT_EXIST   if the desired task has not been created or is assigned to a Mutex PIP
*              OS_TASK_OPT_ERR     if you did NOT specified OS_TASK_OPT_STK_CHK when the task was created
*********************************************************************************************************
*/
#if OS_TASK_CREATE_EXT_EN > 0
INT8U  OSTaskStkChk (INT8U prio, OS_STK_DATA *p_stk_data)
{
    OS_TCB    *ptcb;
    OS_STK    *pchk;
    INT32U     free;
    INT32U     size;
#if OS_CRITICAL_METHOD == 3                            /* Allocate storage for CPU status register     */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                        /* Prevent compiler warning                     */
#endif    
#if OS_ARG_CHK_EN > 0
    if (prio > OS_LOWEST_PRIO) {					   /* Make sure task priority is valid             */
        if (prio != OS_PRIO_SELF) {        
            return (OS_PRIO_INVALID);
        }
    }
#endif
    p_stk_data->OSFree = 0;                            /* Assume failure, set to 0 size                */
    p_stk_data->OSUsed = 0;
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                        /* See if check for SELF                        */
        prio = OSTCBCur->OSTCBPrio;
    }
    ptcb = OSTCBPrioTbl[prio];
    if (ptcb == (OS_TCB *)0) {                         /* Make sure task exist                         */
        OS_EXIT_CRITICAL();
        return (OS_TASK_NOT_EXIST);
    }
    if (ptcb == (OS_TCB *)1) {
        OS_EXIT_CRITICAL();
        return (OS_TASK_NOT_EXIST);
    }  
    if ((ptcb->OSTCBOpt & OS_TASK_OPT_STK_CHK) == 0) { /* Make sure stack checking option is set       */
        OS_EXIT_CRITICAL();
        return (OS_TASK_OPT_ERR);
    }
    free = 0;
    size = ptcb->OSTCBStkSize;
    pchk = ptcb->OSTCBStkBottom;
    OS_EXIT_CRITICAL();
#if OS_STK_GROWTH == 1
    while (*pchk++ == (OS_STK)0) {                    /* Compute the number of zero entries on the stk */
        free++;
    }
#else
    while (*pchk-- == (OS_STK)0) {
        free++;
    }
#endif
    p_stk_data->OSFree = free * sizeof(OS_STK);           /* Compute number of free bytes on the stack */
    p_stk_data->OSUsed = (size - free) * sizeof(OS_STK);  /* Compute number of bytes used on the stack */
    return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                            SUSPEND A TASK
*
* Description: This function is called to suspend a task.  The task can be the calling task if the
*              priority passed to OSTaskSuspend() is the priority of the calling task or OS_PRIO_SELF.
*
* Arguments  : prio     is the priority of the task to suspend.  If you specify OS_PRIO_SELF, the
*                       calling task will suspend itself and rescheduling will occur.
*
* Returns    : OS_NO_ERR                if the requested task is suspended
*              OS_TASK_SUSPEND_IDLE     if you attempted to suspend the idle task which is not allowed.
*              OS_PRIO_INVALID          if the priority you specify is higher that the maximum allowed
*                                       (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
*              OS_TASK_SUSPEND_PRIO     if the task to suspend does not exist
*              OS_TASK_NOT_EXITS        if the task is assigned to a Mutex PIP
*
* Note       : You should use this function with great care.  If you suspend a task that is waiting for
*              an event (i.e. a message, a semaphore, a queue ...) you will prevent this task from
*              running when the event arrives.
*********************************************************************************************************
*/

#if OS_TASK_SUSPEND_EN > 0
INT8U  OSTaskSuspend (INT8U prio)
{
    BOOLEAN    self;
    OS_TCB    *ptcb;
	INT8U      y;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                                 /* Prevent compiler warning            */
#endif    
#if OS_ARG_CHK_EN > 0
    if (prio == OS_IDLE_PRIO) {                                 /* Not allowed to suspend idle task    */
        return (OS_TASK_SUSPEND_IDLE);
    }
    if (prio >= OS_LOWEST_PRIO) {								/* Task priority valid ?               */
        if (prio != OS_PRIO_SELF) {
            return (OS_PRIO_INVALID);
        }
    }
#endif
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                                 /* See if suspend SELF                 */
        prio = OSTCBCur->OSTCBPrio;
        self = TRUE;
    } else if (prio == OSTCBCur->OSTCBPrio) {                   /* See if suspending self              */
        self = TRUE;
    } else {
        self = FALSE;                                           /* No suspending another task          */
    }
    ptcb = OSTCBPrioTbl[prio];
    if (ptcb == (OS_TCB *)0) {                                  /* Task to suspend must exist          */
        OS_EXIT_CRITICAL();
        return (OS_TASK_SUSPEND_PRIO);
    }
    if (ptcb == (OS_TCB *)1) {                                  /* See if assigned to Mutex            */
        OS_EXIT_CRITICAL();
        return (OS_TASK_NOT_EXIST);
    }
	y            = ptcb->OSTCBY;
	OSRdyTbl[y] &= ~ptcb->OSTCBBitX;							/* Make task not ready                 */
    if (OSRdyTbl[y] == 0x00) { 
        OSRdyGrp &= ~ptcb->OSTCBBitY;
    }
    ptcb->OSTCBStat |= OS_STAT_SUSPEND;                         /* Status of task is 'SUSPENDED'       */
    OS_EXIT_CRITICAL();
    if (self == TRUE) {                                         /* Context switch only if SELF         */
        OS_Sched();
    }
    return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                            QUERY A TASK
*
* Description: This function is called to obtain a copy of the desired task's TCB.
*
* Arguments  : prio         is the priority of the task to obtain information from.
*
*              p_task_data  is a pointer to where the desired task's OS_TCB will be stored.
*
* Returns    : OS_NO_ERR          if the requested task is suspended
*              OS_PRIO_INVALID    if the priority you specify is higher that the maximum allowed
*                                 (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
*              OS_PRIO_ERR        if the desired task has not been created
*              OS_TASK_NOT_EXIST  if the task is assigned to a Mutex PIP
*********************************************************************************************************
*/

#if OS_TASK_QUERY_EN > 0
INT8U  OSTaskQuery (INT8U prio, OS_TCB *p_task_data)
{
    OS_TCB    *ptcb;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                  /* Prevent compiler warning                           */
#endif    
#if OS_ARG_CHK_EN > 0
    if (prio > OS_LOWEST_PRIO) {				 /* Task priority valid ?    	                       */
        if (prio != OS_PRIO_SELF) {   
            return (OS_PRIO_INVALID);
        }
    }
#endif
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                  /* See if suspend SELF                                */
        prio = OSTCBCur->OSTCBPrio;
    }
    ptcb = OSTCBPrioTbl[prio];
    if (ptcb == (OS_TCB *)0) {                   /* Task to query must exist                           */
        OS_EXIT_CRITICAL();
        return (OS_PRIO_ERR);
    }
    if (ptcb == (OS_TCB *)1) {                   /* Task to query must not be assigned to a Mutex      */
        OS_EXIT_CRITICAL();
        return (OS_TASK_NOT_EXIST);
    }
                                                 /* Copy TCB into user storage area                    */
    OS_MemCopy((INT8U *)p_task_data, (INT8U *)ptcb, sizeof(OS_TCB));  
    OS_EXIT_CRITICAL();
    return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                        CLEAR TASK STACK
*
* Description: This function is used to clear the stack of a task (i.e. write all zeros)
*
* Arguments  : pbos     is a pointer to the task's bottom of stack.  If the configuration constant
*                       OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
*                       memory to low memory).  'pbos' will thus point to the lowest (valid) memory
*                       location of the stack.  If OS_STK_GROWTH is set to 0, 'pbos' will point to the
*                       highest memory location of the stack and the stack will grow with increasing
*                       memory locations.  'pbos' MUST point to a valid 'free' data item.
*
*              size     is the number of 'stack elements' to clear.
*
*              opt      contains additional information (or options) about the behavior of the task.  The
*                       LOWER 8-bits are reserved by uC/OS-II while the upper 8 bits can be application
*                       specific.  See OS_TASK_OPT_??? in uCOS-II.H.
*
* Returns    : none
*********************************************************************************************************
*/
#if OS_TASK_CREATE_EXT_EN > 0
void  OS_TaskStkClr (OS_STK *pbos, INT32U size, INT16U opt)
{
    if ((opt & OS_TASK_OPT_STK_CHK) != 0x0000) {       /* See if stack checking has been enabled       */
        if ((opt & OS_TASK_OPT_STK_CLR) != 0x0000) {   /* See if stack needs to be cleared             */
#if OS_STK_GROWTH == 1                     
            while (size > 0) {                         /* Stack grows from HIGH to LOW memory          */
                size--;
                *pbos++ = (OS_STK)0;                   /* Clear from bottom of stack and up!           */
            }
#else
            while (size > 0) {                         /* Stack grows from LOW to HIGH memory          */
                size--;
                *pbos-- = (OS_STK)0;                   /* Clear from bottom of stack and down          */
            }
#endif
        }
    }
}

#endif