os_core.c

UCOS-III

    if (OSRunning != OS_STATE_OS_RUNNING) {                 /* Has the OS started?                                    */
        return;                                             /* No                                                     */
    }

    CPU_INT_DIS();
    if (OSIntNestingCtr == (OS_NESTING_CTR)0) {             /* Prevent OSIntNestingCtr from wrapping                  */
        CPU_INT_EN();
        return;
    }
    OSIntNestingCtr--;
    if (OSIntNestingCtr > (OS_NESTING_CTR)0) {              /* ISRs still nested?                                     */
        CPU_INT_EN();                                       /* Yes                                                    */
        return;
    }

    if (OSSchedLockNestingCtr > (OS_NESTING_CTR)0) {        /* Scheduler still locked?                                */
        CPU_INT_EN();                                       /* Yes                                                    */
        return;
    }

    OSPrioHighRdy   = OS_PrioGetHighest();                  /* Find highest priority                                  */
    OSTCBHighRdyPtr = OSRdyList[OSPrioHighRdy].HeadPtr;     /* Get highest priority task ready-to-run                 */
    if (OSTCBHighRdyPtr == OSTCBCurPtr) {                   /* Current task still the highest priority?               */
        CPU_INT_EN();                                       /* Yes                                                    */
        return;
    }

#if OS_CFG_TASK_PROFILE_EN > 0u
    OSTCBHighRdyPtr->CtxSwCtr++;                            /* Inc. # of context switches for this new task           */
#endif
    OSTaskCtxSwCtr++;                                       /* Keep track of the total number of ctx switches         */

    OSIntCtxSw();                                           /* Perform interrupt level ctx switch                     */
    CPU_INT_EN();
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                    INDICATE THAT IT'S NO LONGER SAFE TO CREATE OBJECTS
*
* Description: This function is called by the application code to indicate that all initialization has been completed
*              and that kernel objects are no longer allowed to be created.
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : none
************************************************************************************************************************
*/

#ifdef OS_SAFETY_CRITICAL_IEC61508
void  OSSafetyCriticalStart (void)
{
    OSSafetyCriticalStartFlag = DEF_TRUE;
}

#endif

/*$PAGE*/
/*
************************************************************************************************************************
*                                                      SCHEDULER
*
* Description: This function is called by other uC/OS-III services to determine whether a new, high priority task has
*              been made ready to run.  This function is invoked by TASK level code and is not used to reschedule tasks
*              from ISRs (see OSIntExit() for ISR rescheduling).
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : 1) Rescheduling is prevented when the scheduler is locked (see OSSchedLock())
************************************************************************************************************************
*/

void  OSSched (void)
{
    CPU_SR_ALLOC();



    if (OSIntNestingCtr > (OS_NESTING_CTR)0) {              /* ISRs still nested?                                     */
        return;                                             /* Yes ... only schedule when no nested ISRs              */
    }

    if (OSSchedLockNestingCtr > (OS_NESTING_CTR)0) {        /* Scheduler locked?                                      */
        return;                                             /* Yes                                                    */
    }

    CPU_INT_DIS();
    OSPrioHighRdy   = OS_PrioGetHighest();                  /* Find the highest priority ready                        */
    OSTCBHighRdyPtr = OSRdyList[OSPrioHighRdy].HeadPtr;
    if (OSTCBHighRdyPtr == OSTCBCurPtr) {                   /* Current task is still highest priority task?           */
        CPU_INT_EN();                                       /* Yes ... no need to context switch                      */
        return;
    }

#if OS_CFG_TASK_PROFILE_EN > 0u
    OSTCBHighRdyPtr->CtxSwCtr++;                            /* Inc. # of context switches to this task                */
#endif
    OSTaskCtxSwCtr++;                                       /* Increment context switch counter                       */

    OS_TASK_SW();                                           /* Perform a task level context switch                    */
    CPU_INT_EN();
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                 PREVENT SCHEDULING
*
* Description: This function is used to prevent rescheduling from taking place.  This allows your application to prevent
*              context switches until you are ready to permit context switching.
*
* Arguments  : p_err     is a pointer to a variable that will receive an error code:
*
*                            OS_ERR_NONE                 The scheduler is locked
*                            OS_ERR_LOCK_NESTING_OVF     If you attempted to nest call to this function > 250 levels
*                            OS_ERR_OS_NOT_RUNNING       If uC/OS-III is not running yet.
*                            OS_ERR_SCHED_LOCK_ISR       If you called this function from an ISR.
*
* Returns    : none
*
* Note(s)    : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair.  In other words, for every
*                 call to OSSchedLock() you MUST have a call to OSSchedUnlock().
************************************************************************************************************************
*/

void  OSSchedLock (OS_ERR  *p_err)
{
    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) {              /* Not allowed to call from an ISR                        */
        *p_err = OS_ERR_SCHED_LOCK_ISR;
        return;
    }
#endif

    if (OSRunning != OS_STATE_OS_RUNNING) {                 /* Make sure multitasking is running                      */
       *p_err = OS_ERR_OS_NOT_RUNNING;
        return;
    }

    if (OSSchedLockNestingCtr >= (OS_NESTING_CTR)250u) {    /* Prevent OSSchedLockNestingCtr overflowing              */
       *p_err = OS_ERR_LOCK_NESTING_OVF;
        return;
    }

    CPU_CRITICAL_ENTER();
    OSSchedLockNestingCtr++;                                /* Increment lock nesting level                           */
#if OS_CFG_SCHED_LOCK_TIME_MEAS_EN > 0u
    OS_SchedLockTimeMeasStart();
#endif
    CPU_CRITICAL_EXIT();
   *p_err = OS_ERR_NONE;
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                  ENABLE SCHEDULING
*
* Description: This function is used to re-allow rescheduling.
*
* Arguments  : p_err     is a pointer to a variable that will contain an error code returned by this function.
*
*                            OS_ERR_NONE
*                            OS_ERR_OS_NOT_RUNNING       The scheduler has been enabled
*                            OS_ERR_SCHED_LOCKED         The scheduler is still locked, still nested
*                            OS_ERR_SCHED_NOT_LOCKED     The scheduler was not locked
*                            OS_ERR_SCHED_UNLOCK_ISR     If you called this function from an ISR.
*
* Returns    : none
*
* Note(s)    : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair.  In other words, for every call to
*                 OSSchedLock() you MUST have a call to OSSchedUnlock().
************************************************************************************************************************
*/

void  OSSchedUnlock (OS_ERR  *p_err)
{
    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) {              /* Not allowed to call from an ISR                        */
        *p_err = OS_ERR_SCHED_UNLOCK_ISR;
        return;
    }
#endif

    if (OSRunning != OS_STATE_OS_RUNNING) {                 /* Make sure multitasking is running                      */
       *p_err = OS_ERR_OS_NOT_RUNNING;
        return;
    }

    if (OSSchedLockNestingCtr == (OS_NESTING_CTR)0) {       /* See if the scheduler is locked                         */
       *p_err = OS_ERR_SCHED_NOT_LOCKED;
        return;
    }

    CPU_CRITICAL_ENTER();
    OSSchedLockNestingCtr--;                                /* Decrement lock nesting level                           */
    if (OSSchedLockNestingCtr > (OS_NESTING_CTR)0) {
        CPU_CRITICAL_EXIT();                                /* Scheduler is still locked                              */
       *p_err = OS_ERR_SCHED_LOCKED;
        return;
    }

#if OS_CFG_SCHED_LOCK_TIME_MEAS_EN > 0u
    OS_SchedLockTimeMeasStop();
#endif

    CPU_CRITICAL_EXIT();                                    /* Scheduler should be re-enabled                         */
    OSSched();                                              /* Run the scheduler                                      */
   *p_err = OS_ERR_NONE;
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                      CONFIGURE ROUND-ROBIN SCHEDULING PARAMETERS
*
* Description: This function is called to change the round-robin scheduling parameters.
*
* Arguments  : en                determines whether round-robin will be enabled (when DEF_EN) or not (when DEF_DIS)
*
*              dflt_time_quanta  default number of ticks between time slices.  0 means assumes OSCfg_TickRate_Hz / 10.
*
*              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
*
* Returns    : none
************************************************************************************************************************
*/

#if OS_CFG_SCHED_ROUND_ROBIN_EN > 0u
void  OSSchedRoundRobinCfg (CPU_BOOLEAN  en,
                            OS_TICK      dflt_time_quanta,
                            OS_ERR      *p_err)
{
    CPU_SR_ALLOC();



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

    CPU_CRITICAL_ENTER();
    if (en != DEF_ENABLED) {
        OSSchedRoundRobinEn = DEF_DISABLED;
    } else {
        OSSchedRoundRobinEn = DEF_ENABLED;
    }