os_core.c

UCOS-III

    if (dflt_time_quanta > (OS_TICK)0) {
        OSSchedRoundRobinDfltTimeQuanta = dflt_time_quanta;
    } else {
        OSSchedRoundRobinDfltTimeQuanta = (OS_TICK)(OSCfg_TickRate_Hz / (OS_RATE_HZ)10);
    }
    CPU_CRITICAL_EXIT();
   *p_err = OS_ERR_NONE;
}
#endif

/*$PAGE*/
/*
************************************************************************************************************************
*                                    YIELD CPU WHEN TASK NO LONGER NEEDS THE TIME SLICE
*
* Description: This function is called to give up the CPU when it is done executing before its time slice expires.
*
* Argument(s): p_err      is a pointer to a variable that will contain an error code returned by this function.
*
*                             OS_ERR_NONE                   The call was successful
*                             OS_ERR_ROUND_ROBIN_1          Only 1 task at this priority, nothing to yield to
*                             OS_ERR_ROUND_ROBIN_DISABLED   Round Robin is not enabled
*                             OS_ERR_SCHED_LOCKED           The scheduler has been locked
*                             OS_ERR_YIELD_ISR              Can't be called from an ISR
*
* Returns    : none
*
* Note(s)    : 1) This function MUST be called from a task.
************************************************************************************************************************
*/

#if OS_CFG_SCHED_ROUND_ROBIN_EN > 0u
void  OSSchedRoundRobinYield (OS_ERR  *p_err)
{
    OS_RDY_LIST  *p_rdy_list;
    OS_TCB       *p_tcb;
    CPU_SR_ALLOC();



#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return;
    }
#endif

#if OS_CFG_CALLED_FROM_ISR_CHK_EN > 0u
    if (OSIntNestingCtr > (OS_NESTING_CTR)0) {              /* Can't call this function from an ISR                   */
       *p_err = OS_ERR_YIELD_ISR;
        return;
    }
#endif

    if (OSSchedLockNestingCtr > (OS_NESTING_CTR)0) {        /* Can't yield if the scheduler is locked                 */
       *p_err = OS_ERR_SCHED_LOCKED;
        return;
    }

    if (OSSchedRoundRobinEn != DEF_TRUE) {                  /* Make sure round-robin has been enabled                 */
       *p_err = OS_ERR_ROUND_ROBIN_DISABLED;
        return;
    }

    CPU_CRITICAL_ENTER();
    p_rdy_list = &OSRdyList[OSPrioCur];                     /* Can't yield if it's the only task at that priority     */
    if (p_rdy_list->NbrEntries < (OS_OBJ_QTY)2) {
        CPU_CRITICAL_EXIT();
       *p_err = OS_ERR_ROUND_ROBIN_1;
        return;
    }

    OS_RdyListMoveHeadToTail(p_rdy_list);                   /* Move current OS_TCB to the end of the list             */
    p_tcb = p_rdy_list->HeadPtr;                            /* Point to new OS_TCB at head of the list                */
    if (p_tcb->TimeQuanta == (OS_TICK)0) {                  /* See if we need to use the default time slice           */
        p_tcb->TimeQuantaCtr = OSSchedRoundRobinDfltTimeQuanta;
    } else {
        p_tcb->TimeQuantaCtr = p_tcb->TimeQuanta;           /* Load time slice counter with new time                  */
    }

    CPU_CRITICAL_EXIT();

    OSSched();                                              /* Run new task                                           */
   *p_err = OS_ERR_NONE;
}
#endif

/*$PAGE*/
/*
************************************************************************************************************************
*                                                 START MULTITASKING
*
* Description: This function is used to start the multitasking process which lets uC/OS-III manages the task that you
*              created.  Before you can call OSStart(), you MUST have called OSInit() and you MUST have created at least
*              one application task.
*
* Argument(s): p_err      is a pointer to a variable that will contain an error code returned by this function.
*
*                             OS_ERR_FATAL_RETURN    OS was running and OSStart() returned.
*                             OS_ERR_OS_RUNNING      OS is already running, OSStart() has no effect
*
* Returns    : none
*
* Note(s)    : 1) OSStartHighRdy() MUST:
*                 a) Call OSTaskSwHook() then,
*                 b) Load the context of the task pointed to by OSTCBHighRdyPtr.
*                 c) Execute the task.
*
*              2) OSStart() is not supposed to return.  If it does, that would be considered a fatal error.
************************************************************************************************************************
*/

void  OSStart (OS_ERR  *p_err)
{
#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return;
    }
#endif

    if (OSRunning == OS_STATE_OS_STOPPED) {
        OSPrioHighRdy   = OS_PrioGetHighest();              /* Find the highest priority                              */
        OSPrioCur       = OSPrioHighRdy;
        OSTCBHighRdyPtr = OSRdyList[OSPrioHighRdy].HeadPtr;
        OSTCBCurPtr     = OSTCBHighRdyPtr;
        OSRunning       = OS_STATE_OS_RUNNING;
        OSStartHighRdy();                                   /* Execute target specific code to start task             */
       *p_err           = OS_ERR_FATAL_RETURN;              /* OSStart() is not supposed to return                    */
    } else {
       *p_err           = OS_ERR_OS_RUNNING;                /* OS is already running                                  */
    }
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                    GET VERSION
*
* Description: This function is used to return the version number of uC/OS-III.  The returned value corresponds to
*              uC/OS-III's version number multiplied by 10000.  In other words, version 3.01.02 would be returned as 30102.
*
* Arguments  : p_err   is a pointer to a variable that will receive an error code.  However, OSVersion() set this
*                      variable to
*
*                         OS_ERR_NONE
*
* Returns    : The version number of uC/OS-III multiplied by 10000.
************************************************************************************************************************
*/

CPU_INT16U  OSVersion (OS_ERR  *p_err)
{
#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return ((CPU_INT16U)0u);
    }
#endif

   *p_err = OS_ERR_NONE;
    return (OS_VERSION);
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                      IDLE TASK
*
* Description: This task is internal to uC/OS-III and executes whenever no other higher priority tasks executes because
*              they are ALL waiting for event(s) to occur.
*
* Arguments  : p_arg    is an argument passed to the task when the task is created.
*
* Returns    : none
*
* Note(s)    : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
*
*              2) OSIdleTaskHook() is called after the critical section to ensure that interrupts will be enabled for at
*                 least a few instructions.  On some processors (ex. Philips XA), enabling and then disabling interrupts
*                 doesn't allow the processor enough time to have interrupts enabled before they were disabled again.
*                 uC/OS-III would thus never recognize interrupts.
*
*              3) This hook has been added to allow you to do such things as STOP the CPU to conserve power.
************************************************************************************************************************
*/

void  OS_IdleTask (void *p_arg)
{
    CPU_SR_ALLOC();



    p_arg = p_arg;                                          /* Prevent compiler warning for not using 'p_arg'         */

    while (DEF_ON) {
        CPU_CRITICAL_ENTER();
        OSIdleTaskCtr++;
#if OS_CFG_STAT_TASK_EN > 0u
        OSStatTaskCtr++;
#endif
        CPU_CRITICAL_EXIT();

        OSIdleTaskHook();                                   /* Call user definable HOOK                               */
    }
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                               INITIALIZE THE IDLE TASK
*
* Description: This function initializes the idle task
*
* Arguments  : p_err    is a pointer to a variable that will contain an error code returned by this function.
*
* Returns    : none
*
* Note(s)    : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
************************************************************************************************************************
*/

void  OS_IdleTaskInit (OS_ERR  *p_err)
{
#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return;
    }
#endif

    OSIdleTaskCtr = (OS_IDLE_CTR)0;
                                                            /* ---------------- CREATE THE IDLE TASK ---------------- */
    OSTaskCreate((OS_TCB     *)&OSIdleTaskTCB,
                 (CPU_CHAR   *)((void *)"uC/OS-III Idle Task"),
                 (OS_TASK_PTR)OS_IdleTask,
                 (void       *)0,
                 (OS_PRIO     )(OS_CFG_PRIO_MAX - 1u),
                 (CPU_STK    *)OSCfg_IdleTaskStkBasePtr,
                 (CPU_STK_SIZE)OSCfg_IdleTaskStkLimit,
                 (CPU_STK_SIZE)OSCfg_IdleTaskStkSize,
                 (OS_MSG_QTY  )0u,
                 (OS_TICK     )0u,
                 (void       *)0,
                 (OS_OPT      )(OS_OPT_TASK_STK_CHK | OS_OPT_TASK_STK_CLR),
                 (OS_ERR     *)p_err);
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                             BLOCK A TASK PENDING ON EVENT
*
* Description: This function is called to place a task in the blocked state waiting for an event to occur. This function
*              exist because it is common to a number of OSxxxPend() services.
*
* Arguments  : p_pend_data    is a pointer to an object used to link the task being blocked to the list of task(s)
*              -----------    pending on the desired object.

*              p_obj          is a pointer to the object to pend on.  If there are no object used to pend on then
*              -----          the caller must pass a NULL pointer.
*
*              pending_on     Specifies what the task will be pending on:
*
*                                 OS_TASK_PEND_ON_FLAG
*                                 OS_TASK_PEND_ON_TASK_Q     <- No object (pending for a message sent to the task)
*                                 OS_TASK_PEND_ON_MUTEX
*                                 OS_TASK_PEND_ON_Q
*                                 OS_TASK_PEND_ON_SEM
*                                 OS_TASK_PEND_ON_TASK_SEM   <- No object (pending on a signal sent to the task)
*
*              timeout        Is the amount of time the task will wait for the event to occur.
*
* Returns    : none
*
* Note(s)    : 1) This function is INTERNAL to uC/OS-III and your application MUST NOT call it.
************************************************************************************************************************
*/

void  OS_Pend (OS_PEND_DATA  *p_pend_data,