os_task.c

ucosii 实例

    BOOLEAN    self;
    OS_TCB    *ptcb;
    INT8U      y;
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr = 0u;
#endif



#if OS_ARG_CHK_EN > 0u
    if (prio == OS_TASK_IDLE_PRIO) {                            /* Not allowed to suspend idle task    */
        return (OS_ERR_TASK_SUSPEND_IDLE);
    }
    if (prio >= OS_LOWEST_PRIO) {                               /* Task priority valid ?               */
        if (prio != OS_PRIO_SELF) {
            return (OS_ERR_PRIO_INVALID);
        }
    }
#endif
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                                 /* See if suspend SELF                 */
        prio = OSTCBCur->OSTCBPrio;
        self = OS_TRUE;
    } else if (prio == OSTCBCur->OSTCBPrio) {                   /* See if suspending self              */
        self = OS_TRUE;
    } else {
        self = OS_FALSE;                                        /* No suspending another task          */
    }
    ptcb = OSTCBPrioTbl[prio];
    if (ptcb == (OS_TCB *)0) {                                  /* Task to suspend must exist          */
        OS_EXIT_CRITICAL();
        return (OS_ERR_TASK_SUSPEND_PRIO);
    }
    if (ptcb == OS_TCB_RESERVED) {                              /* See if assigned to Mutex            */
        OS_EXIT_CRITICAL();
        return (OS_ERR_TASK_NOT_EXIST);
    }
    y            = ptcb->OSTCBY;
    OSRdyTbl[y] &= (OS_PRIO)~ptcb->OSTCBBitX;                   /* Make task not ready                 */
    if (OSRdyTbl[y] == 0u) {
        OSRdyGrp &= (OS_PRIO)~ptcb->OSTCBBitY;
    }
    ptcb->OSTCBStat |= OS_STAT_SUSPEND;                         /* Status of task is 'SUSPENDED'       */
    OS_EXIT_CRITICAL();
    if (self == OS_TRUE) {                                      /* Context switch only if SELF         */
        OS_Sched();                                             /* Find new highest priority task      */
    }
    return (OS_ERR_NONE);
}
#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_ERR_NONE            if the requested task is suspended
*              OS_ERR_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_ERR_PRIO            if the desired task has not been created
*              OS_ERR_TASK_NOT_EXIST  if the task is assigned to a Mutex PIP
*              OS_ERR_PDATA_NULL      if 'p_task_data' is a NULL pointer
*********************************************************************************************************
*/

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



#if OS_ARG_CHK_EN > 0u
    if (prio > OS_LOWEST_PRIO) {                 /* Task priority valid ?                              */
        if (prio != OS_PRIO_SELF) {
            return (OS_ERR_PRIO_INVALID);
        }
    }
    if (p_task_data == (OS_TCB *)0) {            /* Validate 'p_task_data'                             */
        return (OS_ERR_PDATA_NULL);
    }
#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_ERR_PRIO);
    }
    if (ptcb == OS_TCB_RESERVED) {               /* Task to query must not be assigned to a Mutex      */
        OS_EXIT_CRITICAL();
        return (OS_ERR_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_ERR_NONE);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                 GET THE CURRENT VALUE OF A TASK REGISTER
*
* Description: This function is called to obtain the current value of a task register.  Task registers
*              are application specific and can be used to store task specific values such as 'error
*              numbers' (i.e. errno), statistics, etc.  Each task register can hold a 32-bit value.
*
* Arguments  : prio      is the priority of the task you want to get the task register from.  If you
*                        specify OS_PRIO_SELF then the task register of the current task will be obtained.
*
*              id        is the 'id' of the desired task register.  Note that the 'id' must be less
*                        than OS_TASK_REG_TBL_SIZE
*
*              perr      is a pointer to a variable that will hold an error code related to this call.
*
*                        OS_ERR_NONE            if the call was successful
*                        OS_ERR_PRIO_INVALID    if you specified an invalid priority
*                        OS_ERR_ID_INVALID      if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1
*
* Returns    : The current value of the task's register or 0 if an error is detected.
*
* Note(s)    : The maximum number of task variables is 254
*********************************************************************************************************
*/

#if OS_TASK_REG_TBL_SIZE > 0u
INT32U  OSTaskRegGet (INT8U   prio,
                      INT8U   id,
                      INT8U  *perr)
{
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr = 0u;
#endif
    INT32U     value;
    OS_TCB    *ptcb;


#if OS_ARG_CHK_EN > 0u
    if (prio >= OS_LOWEST_PRIO) {
        if (prio != OS_PRIO_SELF) {
            *perr = OS_ERR_PRIO_INVALID;
            return (0u);
        }
    }
    if (id >= OS_TASK_REG_TBL_SIZE) {
        *perr = OS_ERR_ID_INVALID;
        return (0u);
    }
#endif
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                  /* See if need to get register from current task      */
        ptcb = OSTCBCur;
    } else {
        ptcb = OSTCBPrioTbl[prio];
    }
    value = ptcb->OSTCBRegTbl[id];
    OS_EXIT_CRITICAL();
    *perr = OS_ERR_NONE;
    return (value);
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                 SET THE CURRENT VALUE OF A TASK VARIABLE
*
* Description: This function is called to change the current value of a task register.  Task registers
*              are application specific and can be used to store task specific values such as 'error
*              numbers' (i.e. errno), statistics, etc.  Each task register can hold a 32-bit value.
*
* Arguments  : prio      is the priority of the task you want to set the task register for.  If you
*                        specify OS_PRIO_SELF then the task register of the current task will be obtained.
*
*              id        is the 'id' of the desired task register.  Note that the 'id' must be less
*                        than OS_TASK_REG_TBL_SIZE
*
*              value     is the desired value for the task register.
*
*              perr      is a pointer to a variable that will hold an error code related to this call.
*
*                        OS_ERR_NONE            if the call was successful
*                        OS_ERR_PRIO_INVALID    if you specified an invalid priority
*                        OS_ERR_ID_INVALID      if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1
*
* Returns    : The current value of the task's variable or 0 if an error is detected.
*
* Note(s)    : The maximum number of task variables is 254
*********************************************************************************************************
*/

#if OS_TASK_REG_TBL_SIZE > 0u
void  OSTaskRegSet (INT8U    prio,
                    INT8U    id,
                    INT32U   value,
                    INT8U   *perr)
{
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr = 0u;
#endif
    OS_TCB    *ptcb;


#if OS_ARG_CHK_EN > 0u
    if (prio >= OS_LOWEST_PRIO) {
        if (prio != OS_PRIO_SELF) {
            *perr = OS_ERR_PRIO_INVALID;
            return;
        }
    }
    if (id >= OS_TASK_REG_TBL_SIZE) {
        *perr = OS_ERR_ID_INVALID;
        return;
    }
#endif
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                  /* See if need to get register from current task      */
        ptcb = OSTCBCur;
    } else {
        ptcb = OSTCBPrioTbl[prio];
    }
    ptcb->OSTCBRegTbl[id] = value;
    OS_EXIT_CRITICAL();
    *perr                 = OS_ERR_NONE;
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                              CATCH ACCIDENTAL TASK RETURN
*
* Description: This function is called if a task accidentally returns without deleting itself.  In other
*              words, a task should either be an infinite loop or delete itself if it's done.
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

void  OS_TaskReturn (void)
{
    OSTaskReturnHook(OSTCBCur);                   /* Call hook to let user decide on what to do        */

#if OS_TASK_DEL_EN > 0u
    (void)OSTaskDel(OS_PRIO_SELF);                /* Delete task if it accidentally returns!           */
#else
    for (;;) {
        OSTimeDly(OS_TICKS_PER_SEC);
    }
#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_STAT_STK_CHK_EN > 0u) && (OS_TASK_CREATE_EXT_EN > 0u)
void  OS_TaskStkClr (OS_STK  *pbos,
                     INT32U   size,
                     INT16U   opt)
{
    if ((opt & OS_TASK_OPT_STK_CHK) != 0x0000u) {      /* See if stack checking has been enabled       */
        if ((opt & OS_TASK_OPT_STK_CLR) != 0x0000u) {  /* See if stack needs to be cleared             */
#if OS_STK_GROWTH == 1u
            while (size > 0u) {                        /* Stack grows from HIGH to LOW memory          */
                size--;
                *pbos++ = (OS_STK)0;                   /* Clear from bottom of stack and up!           */
            }
#else
            while (size > 0u) {                        /* Stack grows from LOW to HIGH memory          */
                size--;
                *pbos-- = (OS_STK)0;                   /* Clear from bottom of stack and down          */
            }
#endif
        }
    }
}

#endif