os_q.src

在51单片机上移植成功的UCOS-II操作系统源代码,包括源代码及相关注释

; *               application MUST NOT call this function.
; *
; * Arguments   :  none
; *
; * Returns     : none
; *********************************************************************************************************
; */
; 
; void OSQInit (void) reentrant
; {
;     INT16U i;
; 
; 
;     for (i = 0; i < (OS_MAX_QS - 1); i++) {      /* Init. list of free QUEUE control blocks            */
;         OSQTbl[i].OSQPtr = &OSQTbl[i+1];
;     }
;     OSQTbl[OS_MAX_QS - 1].OSQPtr = (OS_Q *)0;
;     OSQFreeList                  = &OSQTbl[0];
; }
; 
; /*$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_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 you didn't pass a pointer to a queue.
; *********************************************************************************************************
; */
; 
; void *OSQPend (OS_EVENT *pevent, INT16U timeout, INT8U *err) reentrant
; {
;     void  *msg;
;     OS_Q  *pq;
; 
; 
;     OS_ENTER_CRITICAL();
;     if (pevent->OSEventType != OS_EVENT_TYPE_Q) {/* Validate event block type                          */
;         OS_EXIT_CRITICAL();
;         *err = OS_ERR_EVENT_TYPE;
;         return ((void *)0);
;     }
;     pq = 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;
;     } else if (OSIntNesting > 0) {               /* See if called from ISR ...                         */
;         OS_EXIT_CRITICAL();                      /* ... can't PEND from an ISR                         */
;         *err = OS_ERR_PEND_ISR;
;     } else {
;         OSTCBCur->OSTCBStat    |= OS_STAT_Q;     /* Task will have to pend for a message to be posted  */
;         OSTCBCur->OSTCBDly      = timeout;       /* Load timeout into TCB                              */
;         OSEventTaskWait(pevent);                 /* Suspend task until event or timeout occurs         */
;         OS_EXIT_CRITICAL();
;         OSSched();                               /* Find next highest priority task ready to run       */
;         OS_ENTER_CRITICAL();
;         if ((msg = OSTCBCur->OSTCBMsg) != (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;
;         } else if (OSTCBCur->OSTCBStat & OS_STAT_Q) { /* Timed out if status indicates pending on Q    */
;             OSEventTO(pevent);
;             OS_EXIT_CRITICAL();
;             msg                     = (void *)0;      /* No message received                           */
;             *err                    = OS_TIMEOUT;     /* Indicate a timeout occured                    */
;         } else {
;             msg = *pq->OSQOut++;                      /* Extract message from 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 Q    */
;                 pq->OSQOut = pq->OSQStart;
;             }
;             OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
;             OS_EXIT_CRITICAL();
;             *err = OS_NO_ERR;
;         }
;     }                                                 
;     return (msg);                                     /* Return message received (or NULL)             */
; }
; /*$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.
; *********************************************************************************************************
; */
; 
; INT8U OSQPost (OS_EVENT *pevent, void *msg) reentrant
; {
;     OS_Q   *pq;
; 
; 
;     OS_ENTER_CRITICAL();
;     if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
;         OS_EXIT_CRITICAL();
;         return (OS_ERR_EVENT_TYPE);
;     }
;     if (pevent->OSEventGrp) {                         /* See if any task pending on queue              */
;         OSEventTaskRdy(pevent, msg, OS_STAT_Q);       /* Ready highest priority task waiting on event  */
;         OS_EXIT_CRITICAL();
;         OSSched();                                    /* Find highest priority task ready to run       */
;         return (OS_NO_ERR);
;     } else {
;         pq = 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);
;         } else {
;             *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);
;     }
; }
; /*$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.
; *********************************************************************************************************
; */
; 
; INT8U OSQPostFront (OS_EVENT *pevent, void *msg) reentrant
; {
;     OS_Q   *pq;
; 
; 
;     OS_ENTER_CRITICAL();
;     if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
;         OS_EXIT_CRITICAL();
;         return (OS_ERR_EVENT_TYPE);
;     }
;     if (pevent->OSEventGrp) {                         /* See if any task pending on queue              */
;         OSEventTaskRdy(pevent, msg, OS_STAT_Q);       /* Ready highest priority task waiting on event  */
;         OS_EXIT_CRITICAL();
;         OSSched();                                    /* Find highest priority task ready to run       */
;         return (OS_NO_ERR);
;     } else {
;         pq = 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);
;         } else {
;             if (pq->OSQOut == pq->OSQStart) {         /* Wrap OUT ptr if we are at the 1st queue entry */
;                 pq->OSQOut = pq->OSQEnd;
;             }
;             pq->OSQOut--;
;             *pq->OSQOut = msg;                        /* Insert message into queue                     */
;             pq->OSQEntries++;                         /* Update the nbr of entries in the queue        */
;             OS_EXIT_CRITICAL();
;         }
;         return (OS_NO_ERR);
;     }
; }
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                        QUERY A MESSAGE QUEUE
; *
; * Description: This function obtains information about a message queue.
; *
; * Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox
; *
; *              pdata         is a pointer to a structure that will contain information about the message
; *                            queue.
; *
; * Returns    : OS_NO_ERR          The call was successful and the message was sent
; *              OS_ERR_EVENT_TYPE  If you are attempting to obtain data from a non queue.
; *********************************************************************************************************
; */
; 
; INT8U OSQQuery (OS_EVENT *pevent, OS_Q_DATA *ppdata) reentrant
; {
;     OS_Q   *pq;
;     INT8U   i;
;     INT8U  *psrc;
;     INT8U  *pdest;
;     
;     
;     OS_ENTER_CRITICAL();
;     if (pevent->OSEventType != OS_EVENT_TYPE_Q) {          /* Validate event block type                */
;         OS_EXIT_CRITICAL();
;         return (OS_ERR_EVENT_TYPE);
;     }
;     ppdata->OSEventGrp = pevent->OSEventGrp;                /* Copy message mailbox wait list           */
;     psrc              = &pevent->OSEventTbl[0];
;     pdest             = &ppdata->OSEventTbl[0];
;     for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {
;         *pdest++ = *psrc++;   
;     }
;     pq = (OS_Q *)pevent->OSEventPtr;
;     if (pq->OSQEntries > 0) {
;         ppdata->OSMsg = pq->OSQOut;                         /* Get next message to return if available  */
;     } else {
;         ppdata->OSMsg = (void *)0;
;     }
;     ppdata->OSNMsgs = pq->OSQEntries;
;     ppdata->OSQSize = pq->OSQSize;
;     OS_EXIT_CRITICAL();
;     return (OS_NO_ERR);
; }
; #endif
; *** sync lost ***
; *** sync lost ***
; *** sync lost ***
	END