os_sem.c

官方的UCOSii的移植文件

        return;
    }
    if (OSLockNesting > 0) {                          /* See if called with scheduler locked ...       */
        *perr = OS_ERR_PEND_LOCKED;                   /* ... can't PEND when locked                    */
        return;
    }
    OS_ENTER_CRITICAL();
    if (pevent->OSEventCnt > 0) {                     /* If sem. is positive, resource available ...   */
        pevent->OSEventCnt--;                         /* ... decrement semaphore only if positive.     */
        OS_EXIT_CRITICAL();
        *perr = OS_ERR_NONE;
        return;
    }
                                                      /* Otherwise, must wait until event occurs       */
    OSTCBCur->OSTCBStat     |= OS_STAT_SEM;           /* Resource not available, pend on semaphore     */
    OSTCBCur->OSTCBStatPend  = OS_STAT_PEND_OK;
    OSTCBCur->OSTCBDly       = timeout;               /* Store pend timeout in TCB                     */
    OS_EventTaskWait(pevent);                         /* Suspend task until event or timeout occurs    */
    OS_EXIT_CRITICAL();
    OS_Sched();                                       /* Find next highest priority task ready         */
    OS_ENTER_CRITICAL();
    if (OSTCBCur->OSTCBStatPend != OS_STAT_PEND_OK) { /* See if we timed-out or aborted                */
        pend_stat = OSTCBCur->OSTCBStatPend;
        OS_EventTOAbort(pevent);
        OS_EXIT_CRITICAL();
        switch (pend_stat) {
            case OS_STAT_PEND_TO:
            default:
                 *perr = OS_ERR_TIMEOUT;              /* Indicate that didn't get event within TO      */
                 break;

            case OS_STAT_PEND_ABORT:
                 *perr = OS_ERR_PEND_ABORT;           /* Indicate that we aborted                      */
                 break;
        }
        return;
    }
    OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
    OS_EXIT_CRITICAL();
    *perr = OS_ERR_NONE;
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                      ABORT WAITING ON A SEMAPHORE
*
* Description: This function aborts & readies any tasks currently waiting on a semaphore.  This function 
*              should be used to fault-abort the wait on the semaphore, rather than to normally signal
*              the semaphore via OSSemPost().
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired
*                            semaphore.
*
*              opt           determines the type of ABORT performed:
*                            OS_PEND_OPT_NONE         ABORT wait for a single task (HPT) waiting on the
*                                                     semaphore
*                            OS_PEND_OPT_BROADCAST    ABORT wait for ALL tasks that are  waiting on the
*                                                     semaphore
*
*              perr          is a pointer to where an error message will be deposited.  Possible error
*                            messages are:
*
*                            OS_ERR_NONE         No tasks were     waiting on the semaphore.
*                            OS_ERR_PEND_ABORT   At least one task waiting on the semaphore was readied
*                                                and informed of the aborted wait; check return value 
*                                                for the number of tasks whose wait on the semaphore 
*                                                was aborted.
*                            OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a semaphore.
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer.
*
* Returns    : == 0          if no tasks were waiting on the semaphore, or upon error.
*              >  0          if one or more tasks waiting on the semaphore are now readied and informed.
*********************************************************************************************************
*/

#if OS_SEM_PEND_ABORT_EN > 0
INT8U  OSSemPendAbort (OS_EVENT *pevent, INT8U opt, INT8U *perr)
{
    INT8U      nbr_tasks;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
    OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
    if (perr == (INT8U *)0) {                         /* Validate 'perr'                               */
        return (0);
    }
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */
        *perr = OS_ERR_PEVENT_NULL;
        return (0);
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_SEM) {   /* Validate event block type                     */
        *perr = OS_ERR_EVENT_TYPE;
        return (0);
    }
    OS_ENTER_CRITICAL();
    if (pevent->OSEventGrp != 0) {                    /* See if any task waiting on semaphore?         */
        nbr_tasks = 0;
        switch (opt) {
            case OS_PEND_OPT_BROADCAST:               /* Do we need to abort ALL waiting tasks?        */
                 while (pevent->OSEventGrp != 0) {    /* Yes, ready ALL tasks waiting on semaphore     */
                     (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM, OS_STAT_PEND_ABORT);
                     nbr_tasks++;
                 }
                 break;
                 
            case OS_PEND_OPT_NONE:                    /* No,  ready HPT       waiting on semaphore     */
            default:
                 (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM, OS_STAT_PEND_ABORT);
                 nbr_tasks++;
                 break;
        }
        OS_EXIT_CRITICAL();
        OS_Sched();                                   /* Find HPT ready to run                         */
        *perr = OS_ERR_PEND_ABORT;
        return (nbr_tasks);
    }
    OS_EXIT_CRITICAL();
    *perr = OS_ERR_NONE;
    return (0);                                       /* No tasks waiting on semaphore                 */
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                         POST TO A SEMAPHORE
*
* Description: This function signals a semaphore
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired
*                            semaphore.
*
* Returns    : OS_ERR_NONE         The call was successful and the semaphore was signaled.
*              OS_ERR_SEM_OVF      If the semaphore count exceeded its limit.  In other words, you have
*                                  signalled the semaphore more often than you waited on it with either
*                                  OSSemAccept() or OSSemPend().
*              OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a semaphore
*              OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer.
*********************************************************************************************************
*/

INT8U  OSSemPost (OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
    OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */
        return (OS_ERR_PEVENT_NULL);
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_SEM) {   /* Validate event block type                     */
        return (OS_ERR_EVENT_TYPE);
    }
    OS_ENTER_CRITICAL();
    if (pevent->OSEventGrp != 0) {                    /* See if any task waiting for semaphore         */
                                                      /* Ready HPT waiting on event                    */
        (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM, OS_STAT_PEND_OK);
        OS_EXIT_CRITICAL();
        OS_Sched();                                   /* Find HPT ready to run                         */
        return (OS_ERR_NONE);
    }
    if (pevent->OSEventCnt < 65535u) {                /* Make sure semaphore will not overflow         */
        pevent->OSEventCnt++;                         /* Increment semaphore count to register event   */
        OS_EXIT_CRITICAL();
        return (OS_ERR_NONE);
    }
    OS_EXIT_CRITICAL();                               /* Semaphore value has reached its maximum       */
    return (OS_ERR_SEM_OVF);
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                          QUERY A SEMAPHORE
*
* Description: This function obtains information about a semaphore
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired
*                            semaphore
*
*              p_sem_data    is a pointer to a structure that will contain information about the
*                            semaphore.
*
* Returns    : OS_ERR_NONE         The call was successful and the message was sent
*              OS_ERR_EVENT_TYPE   If you are attempting to obtain data from a non semaphore.
*              OS_ERR_PEVENT_NULL  If 'pevent'     is a NULL pointer.
*              OS_ERR_PDATA_NULL   If 'p_sem_data' is a NULL pointer
*********************************************************************************************************
*/

#if OS_SEM_QUERY_EN > 0
INT8U  OSSemQuery (OS_EVENT *pevent, OS_SEM_DATA *p_sem_data)
{
#if OS_LOWEST_PRIO <= 63
    INT8U     *psrc;
    INT8U     *pdest;
#else
    INT16U    *psrc;
    INT16U    *pdest;
#endif
    INT8U      i;
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */
        return (OS_ERR_PEVENT_NULL);
    }
    if (p_sem_data == (OS_SEM_DATA *)0) {                  /* Validate 'p_sem_data'                    */
        return (OS_ERR_PDATA_NULL);
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_SEM) {        /* Validate event block type                */
        return (OS_ERR_EVENT_TYPE);
    }
    OS_ENTER_CRITICAL();
    p_sem_data->OSEventGrp = pevent->OSEventGrp;           /* Copy message mailbox wait list           */
    psrc                   = &pevent->OSEventTbl[0];
    pdest                  = &p_sem_data->OSEventTbl[0];
    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {
        *pdest++ = *psrc++;
    }
    p_sem_data->OSCnt = pevent->OSEventCnt;                /* Get semaphore count                      */
    OS_EXIT_CRITICAL();
    return (OS_ERR_NONE);
}
#endif                                                     /* OS_SEM_QUERY_EN                          */

/*$PAGE*/
/*
*********************************************************************************************************
*                                              SET SEMAPHORE
*
* Description: This function sets the semaphore count to the value specified as an argument.  Typically,
*              this value would be 0.
*
*              You would typically use this function when a semaphore is used as a signaling mechanism
*              and, you want to reset the count value.
*
* Arguments  : pevent     is a pointer to the event control block
*
*              cnt        is the new value for the semaphore count.  You would pass 0 to reset the
*                         semaphore count.
*
*              perr       is a pointer to an error code returned by the function as follows:
*
*                            OS_ERR_NONE          The call was successful and the semaphore value was set.
*                            OS_ERR_EVENT_TYPE    If you didn't pass a pointer to a semaphore.
*                            OS_ERR_PEVENT_NULL   If 'pevent' is a NULL pointer.
*                            OS_ERR_TASK_WAITING  If tasks are waiting on the semaphore.
*********************************************************************************************************
*/

#if OS_SEM_SET_EN > 0
void  OSSemSet (OS_EVENT *pevent, INT16U cnt, INT8U *perr)
{
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
    OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
    if (perr == (INT8U *)0) {                         /* Validate 'perr'                               */
        return;
    }
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */
        *perr = OS_ERR_PEVENT_NULL;
        return;
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_SEM) {   /* Validate event block type                     */
        *perr = OS_ERR_EVENT_TYPE;
        return;
    }
    OS_ENTER_CRITICAL();
    *perr = OS_ERR_NONE;
    if (pevent->OSEventCnt > 0) {                     /* See if semaphore already has a count          */
        pevent->OSEventCnt = cnt;                     /* Yes, set it to the new value specified.       */
    } else {                                          /* No                                            */
        if (pevent->OSEventGrp == 0) {                /*      See if task(s) waiting?                  */
            pevent->OSEventCnt = cnt;                 /*      No, OK to set the value                  */
        } else {
            *perr              = OS_ERR_TASK_WAITING;
        }
    }
    OS_EXIT_CRITICAL();
}
#endif

#endif                                                /* OS_SEM_EN                                     */