os_q.c

完整的ucos实例

             *err = OS_ERR_INVALID_OPT; 
             return (pevent); 
    } 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                           FLUSH QUEUE 
* 
* Description : This function is used to flush the contents of the message queue. 
* 
* Arguments   : none 
* 
* Returns     : OS_NO_ERR           upon success 
*               OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a queue 
*               OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer 
********************************************************************************************************* 
*/ 
 
#if OS_Q_FLUSH_EN > 0 
INT8U  OSQFlush (OS_EVENT *pevent) 
{ 
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */ 
    OS_CPU_SR  cpu_sr; 
#endif 
    OS_Q      *pq; 
 
 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    pq             = (OS_Q *)pevent->OSEventPtr;      /* Point to queue storage structure              */ 
    pq->OSQIn      = pq->OSQStart; 
    pq->OSQOut     = pq->OSQStart; 
    pq->OSQEntries = 0; 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                     PEND ON A QUEUE FOR A MESSAGE 
* 
* Description: This function waits for a message to be sent to a queue 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue 
* 
*              timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will 
*                            wait for a message to arrive at the queue up to the amount of time 
*                            specified by this argument.  If you specify 0, however, your task will wait 
*                            forever at the specified queue or, until a message arrives. 
* 
*              err           is a pointer to where an error message will be deposited.  Possible error 
*                            messages are: 
* 
*                            OS_NO_ERR           The call was successful and your task received a 
*                                                message. 
*                            OS_TIMEOUT          A message was not received within the specified timeout 
*                            OS_ERR_EVENT_TYPE   You didn't pass a pointer to a queue 
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer 
*                            OS_ERR_PEND_ISR     If you called this function from an ISR and the result 
*                                                would lead to a suspension. 
* 
* Returns    : != (void *)0  is a pointer to the message received 
*              == (void *)0  if no message was received or, 
*                            if 'pevent' is a NULL pointer or, 
*                            if you didn't pass a pointer to a queue. 
********************************************************************************************************* 
*/ 
 
void  *OSQPend (OS_EVENT *pevent, INT16U timeout, INT8U *err) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif 
    void      *msg; 
    OS_Q      *pq; 
 
 
    if (OSIntNesting > 0) {                      /* See if called from ISR ...                         */ 
        *err = OS_ERR_PEND_ISR;                  /* ... can't PEND from an ISR                         */ 
        return ((void *)0); 
    } 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {               /* Validate 'pevent'                                  */ 
        *err = OS_ERR_PEVENT_NULL; 
        return ((void *)0); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {/* Validate event block type                          */ 
        *err = OS_ERR_EVENT_TYPE; 
        return ((void *)0); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    pq = (OS_Q *)pevent->OSEventPtr;             /* Point at queue control block                       */ 
    if (pq->OSQEntries > 0) {                    /* See if any messages in the queue                   */ 
        msg = *pq->OSQOut++;                     /* Yes, extract oldest message from the queue         */ 
        pq->OSQEntries--;                        /* Update the number of entries in the queue          */ 
        if (pq->OSQOut == pq->OSQEnd) {          /* Wrap OUT pointer if we are at the end of the queue */ 
            pq->OSQOut = pq->OSQStart; 
        } 
        OS_EXIT_CRITICAL(); 
        *err = OS_NO_ERR; 
        return (msg);                            /* Return message received                            */ 
    } 
    OSTCBCur->OSTCBStat |= OS_STAT_Q;            /* Task will have to pend for a message to be posted  */ 
    OSTCBCur->OSTCBDly   = timeout;              /* Load timeout into TCB                              */ 
    OS_EventTaskWait(pevent);                    /* Suspend task until event or timeout occurs         */ 
    OS_EXIT_CRITICAL(); 
    OS_Sched();                                  /* Find next highest priority task ready to run       */ 
    OS_ENTER_CRITICAL(); 
    msg = OSTCBCur->OSTCBMsg; 
    if (msg != (void *)0) {                      /* Did we get a message?                              */ 
        OSTCBCur->OSTCBMsg      = (void *)0;     /* Extract message from TCB (Put there by QPost)      */ 
        OSTCBCur->OSTCBStat     = OS_STAT_RDY; 
        OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0; /* No longer waiting for event                        */ 
        OS_EXIT_CRITICAL(); 
        *err                    = OS_NO_ERR; 
        return (msg);                            /* Return message received                            */ 
    } 
    OS_EventTO(pevent);                          /* Timed out                                          */ 
    OS_EXIT_CRITICAL(); 
    *err = OS_TIMEOUT;                           /* Indicate a timeout occured                         */ 
    return ((void *)0);                          /* No message received                                */ 
} 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        POST MESSAGE TO A QUEUE 
* 
* Description: This function sends a message to a queue 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue 
* 
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer. 
* 
* Returns    : OS_NO_ERR             The call was successful and the message was sent 
*              OS_Q_FULL             If the queue cannot accept any more messages because it is full. 
*              OS_ERR_EVENT_TYPE     If you didn't pass a pointer to a queue. 
*              OS_ERR_PEVENT_NULL    If 'pevent' is a NULL pointer 
*              OS_ERR_POST_NULL_PTR  If you are attempting to post a NULL pointer 
********************************************************************************************************* 
*/ 
 
#if OS_Q_POST_EN > 0 
INT8U  OSQPost (OS_EVENT *pevent, void *msg) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif 
    OS_Q      *pq; 
 
 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */ 
        return (OS_ERR_POST_NULL_PTR); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (pevent->OSEventGrp != 0x00) {                 /* See if any task pending on queue              */ 
        OS_EventTaskRdy(pevent, msg, OS_STAT_Q);      /* Ready highest priority task waiting on event  */ 
        OS_EXIT_CRITICAL(); 
        OS_Sched();                                   /* Find highest priority task ready to run       */ 
        return (OS_NO_ERR); 
    } 
    pq = (OS_Q *)pevent->OSEventPtr;                  /* Point to queue control block                  */ 
    if (pq->OSQEntries >= pq->OSQSize) {              /* Make sure queue is not full                   */ 
        OS_EXIT_CRITICAL(); 
        return (OS_Q_FULL); 
    } 
    *pq->OSQIn++ = msg;                               /* Insert message into queue                     */ 
    pq->OSQEntries++;                                 /* Update the nbr of entries in the queue        */ 
    if (pq->OSQIn == pq->OSQEnd) {                    /* Wrap IN ptr if we are at end of queue         */ 
        pq->OSQIn = pq->OSQStart; 
    } 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                   POST MESSAGE TO THE FRONT OF A QUEUE 
* 
* Description: This function sends a message to a queue but unlike OSQPost(), the message is posted at 
*              the front instead of the end of the queue.  Using OSQPostFront() allows you to send 
*              'priority' messages. 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue 
* 
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer. 
* 
* Returns    : OS_NO_ERR             The call was successful and the message was sent 
*              OS_Q_FULL             If the queue cannot accept any more messages because it is full. 
*              OS_ERR_EVENT_TYPE     If you didn't pass a pointer to a queue. 
*              OS_ERR_PEVENT_NULL    If 'pevent' is a NULL pointer 
*              OS_ERR_POST_NULL_PTR  If you are attempting to post to a non queue. 
********************************************************************************************************* 
*/ 
 
#if OS_Q_POST_FRONT_EN > 0 
INT8U  OSQPostFront (OS_EVENT *pevent, void *msg) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif 
    OS_Q      *pq; 
 
 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */ 
        return (OS_ERR_POST_NULL_PTR); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (pevent->OSEventGrp != 0x00) {                 /* See if any task pending on queue              */ 
        OS_EventTaskRdy(pevent, msg, OS_STAT_Q);      /* Ready highest priority task waiting on event  */ 
        OS_EXIT_CRITICAL(); 
        OS_Sched();                                   /* Find highest priority task ready to run       */ 
        return (OS_NO_ERR);