// a queue.
 static void prvCoRoutineFlashTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 {
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
 static portBASE_TYPE xNumberToPost = 0;
 static portBASE_TYPE xResult;

    // Co-routines must begin with a call to crSTART().
    crSTART( xHandle );

    for( ;; )
    {
        // This assumes the queue has already been created.
        crQUEUE_SEND( xHandle, xCoRoutineQueue, &xNumberToPost, NO_DELAY, &xResult );

        if( xResult != pdPASS )
        {
            // The message was not posted!
        }

        // Increment the number to be posted onto the queue.
        xNumberToPost++;

        // Delay for 100 ticks.
        crDELAY( xHandle, 100 );
    }

    // Co-routines must end with a call to crEND().
    crEND();
 }</pre>
 * \defgroup crQUEUE_SEND crQUEUE_SEND
 * \ingroup Tasks
 */
#define crQUEUE_SEND( xHandle, pxQueue, pvItemToQueue, xTicksToWait, pxResult )			\
{																						\
	*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, xTicksToWait );					\
	if( *pxResult == errQUEUE_BLOCKED )													\
	{																					\
		crSET_STATE0( xHandle );														\
		*pxResult = xQueueCRSend( pxQueue, pvItemToQueue, 0 );							\
	}																					\
	if( *pxResult == errQUEUE_YIELD )													\
	{																					\
		crSET_STATE1( xHandle );														\
		*pxResult = pdPASS;																\
	}																					\
}

/**
 * croutine. h
 * <pre>
  crQUEUE_RECEIVE(
                     xCoRoutineHandle xHandle,
                     xQueueHandle pxQueue,
                     void *pvBuffer,
                     portTickType xTicksToWait,
                     portBASE_TYPE *pxResult
                 )</pre>
 *
 * The macro's crQUEUE_SEND() and crQUEUE_RECEIVE() are the co-routine
 * equivalent to the xQueueSend() and xQueueReceive() functions used by tasks.
 *
 * crQUEUE_SEND and crQUEUE_RECEIVE can only be used from a co-routine whereas
 * xQueueSend() and xQueueReceive() can only be used from tasks.
 *
 * crQUEUE_RECEIVE can only be called from the co-routine function itself - not
 * from within a function called by the co-routine function.  This is because
 * co-routines do not maintain their own stack.
 *
 * See the co-routine section of the WEB documentation for information on
 * passing data between tasks and co-routines and between ISR's and
 * co-routines.
 *
 * @param xHandle The handle of the calling co-routine.  This is the xHandle
 * parameter of the co-routine function.
 *
 * @param pxQueue The handle of the queue from which the data will be received.
 * The handle is obtained as the return value when the queue is created using
 * the xQueueCreate() API function.
 *
 * @param pvBuffer The buffer into which the received item is to be copied.
 * The number of bytes of each queued item is specified when the queue is
 * created.  This number of bytes is copied into pvBuffer.
 *
 * @param xTickToDelay The number of ticks that the co-routine should block
 * to wait for data to become available from the queue, should data not be
 * available immediately. The actual amount of time this equates to is defined
 * by configTICK_RATE_HZ (set in FreeRTOSConfig.h).  The constant
 * portTICK_RATE_MS can be used to convert ticks to milliseconds (see the
 * crQUEUE_SEND example).
 *
 * @param pxResult The variable pointed to by pxResult will be set to pdPASS if
 * data was successfully retrieved from the queue, otherwise it will be set to
 * an error code as defined within ProjDefs.h.
 *
 * Example usage:
 <pre>
 // A co-routine receives the number of an LED to flash from a queue.  It
 // blocks on the queue until the number is received.
 static void prvCoRoutineFlashWorkTask( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 {
 // Variables in co-routines must be declared static if they must maintain value across a blocking call.
 static portBASE_TYPE xResult;
 static unsigned portBASE_TYPE uxLEDToFlash;

    // All co-routines must start with a call to crSTART().
    crSTART( xHandle );

    for( ;; )
    {
        // Wait for data to become available on the queue.
        crQUEUE_RECEIVE( xHandle, xCoRoutineQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );

        if( xResult == pdPASS )
        {
            // We received the LED to flash - flash it!
            vParTestToggleLED( uxLEDToFlash );
        }
    }

    crEND();
 }</pre>
 * \defgroup crQUEUE_RECEIVE crQUEUE_RECEIVE
 * \ingroup Tasks
 */
#define crQUEUE_RECEIVE( xHandle, pxQueue, pvBuffer, xTicksToWait, pxResult )			\
{																						\
	*pxResult = xQueueCRReceive( pxQueue, pvBuffer, xTicksToWait );						\
	if( *pxResult == errQUEUE_BLOCKED ) 												\
	{																					\
		crSET_STATE0( xHandle );														\
		*pxResult = xQueueCRReceive( pxQueue, pvBuffer, 0 );							\
	}																					\
	if( *pxResult == errQUEUE_YIELD )													\
	{																					\
		crSET_STATE1( xHandle );														\
		*pxResult = pdPASS;																\
	}																					\
}

/**
 * croutine. h
 * <pre>
  crQUEUE_SEND_FROM_ISR(
                            xQueueHandle pxQueue,
                            void *pvItemToQueue,
                            portBASE_TYPE xCoRoutinePreviouslyWoken
                       )</pre>
 *
 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
 * functions used by tasks.
 *
 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
 * xQueueReceiveFromISR() can only be used to pass data between a task and and
 * ISR.
 *
 * crQUEUE_SEND_FROM_ISR can only be called from an ISR to send data to a queue
 * that is being used from within a co-routine.
 *
 * See the co-routine section of the WEB documentation for information on
 * passing data between tasks and co-routines and between ISR's and
 * co-routines.
 *
 * @param xQueue The handle to the queue on which the item is to be posted.
 *
 * @param pvItemToQueue A pointer to the item that is to be placed on the
 * queue.  The size of the items the queue will hold was defined when the
 * queue was created, so this many bytes will be copied from pvItemToQueue
 * into the queue storage area.
 *
 * @param xCoRoutinePreviouslyWoken This is included so an ISR can post onto
 * the same queue multiple times from a single interrupt.  The first call
 * should always pass in pdFALSE.  Subsequent calls should pass in
 * the value returned from the previous call.
 *
 * @return pdTRUE if a co-routine was woken by posting onto the queue.  This is
 * used by the ISR to determine if a context switch may be required following
 * the ISR.
 *
 * Example usage:
 <pre>
 // A co-routine that blocks on a queue waiting for characters to be received.
 static void vReceivingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 {
 char cRxedChar;
 portBASE_TYPE xResult;

     // All co-routines must start with a call to crSTART().
     crSTART( xHandle );

     for( ;; )
     {
         // Wait for data to become available on the queue.  This assumes the
         // queue xCommsRxQueue has already been created!
         crQUEUE_RECEIVE( xHandle, xCommsRxQueue, &uxLEDToFlash, portMAX_DELAY, &xResult );

         // Was a character received?
         if( xResult == pdPASS )
         {
             // Process the character here.
         }
     }

     // All co-routines must end with a call to crEND().
     crEND();
 }

 // An ISR that uses a queue to send characters received on a serial port to
 // a co-routine.
 void vUART_ISR( void )
 {
 char cRxedChar;
 portBASE_TYPE xCRWokenByPost = pdFALSE;

     // We loop around reading characters until there are none left in the UART.
     while( UART_RX_REG_NOT_EMPTY() )
     {
         // Obtain the character from the UART.
         cRxedChar = UART_RX_REG;

         // Post the character onto a queue.  xCRWokenByPost will be pdFALSE
         // the first time around the loop.  If the post causes a co-routine
         // to be woken (unblocked) then xCRWokenByPost will be set to pdTRUE.
         // In this manner we can ensure that if more than one co-routine is
         // blocked on the queue only one is woken by this ISR no matter how
         // many characters are posted to the queue.
         xCRWokenByPost = crQUEUE_SEND_FROM_ISR( xCommsRxQueue, &cRxedChar, xCRWokenByPost );
     }
 }</pre>
 * \defgroup crQUEUE_SEND_FROM_ISR crQUEUE_SEND_FROM_ISR
 * \ingroup Tasks
 */
#define crQUEUE_SEND_FROM_ISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken ) xQueueCRSendFromISR( pxQueue, pvItemToQueue, xCoRoutinePreviouslyWoken )


/**
 * croutine. h
 * <pre>
  crQUEUE_SEND_FROM_ISR(
                            xQueueHandle pxQueue,
                            void *pvBuffer,
                            portBASE_TYPE * pxCoRoutineWoken
                       )</pre>
 *
 * The macro's crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() are the
 * co-routine equivalent to the xQueueSendFromISR() and xQueueReceiveFromISR()
 * functions used by tasks.
 *
 * crQUEUE_SEND_FROM_ISR() and crQUEUE_RECEIVE_FROM_ISR() can only be used to
 * pass data between a co-routine and and ISR, whereas xQueueSendFromISR() and
 * xQueueReceiveFromISR() can only be used to pass data between a task and and
 * ISR.
 *
 * crQUEUE_RECEIVE_FROM_ISR can only be called from an ISR to receive data
 * from a queue that is being used from within a co-routine (a co-routine
 * posted to the queue).
 *
 * See the co-routine section of the WEB documentation for information on
 * passing data between tasks and co-routines and between ISR's and
 * co-routines.
 *
 * @param xQueue The handle to the queue on which the item is to be posted.
 *
 * @param pvBuffer A pointer to a buffer into which the received item will be
 * placed.  The size of the items the queue will hold was defined when the
 * queue was created, so this many bytes will be copied from the queue into
 * pvBuffer.
 *
 * @param pxCoRoutineWoken A co-routine may be blocked waiting for space to become
 * available on the queue.  If crQUEUE_RECEIVE_FROM_ISR causes such a
 * co-routine to unblock *pxCoRoutineWoken will get set to pdTRUE, otherwise
 * *pxCoRoutineWoken will remain unchanged.
 *
 * @return pdTRUE an item was successfully received from the queue, otherwise
 * pdFALSE.
 *
 * Example usage:
 <pre>
 // A co-routine that posts a character to a queue then blocks for a fixed
 // period.  The character is incremented each time.
 static void vSendingCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
 {
 // cChar holds its value while this co-routine is blocked and must therefore
 // be declared static.
 static char cCharToTx = 'a';
 portBASE_TYPE xResult;

     // All co-routines must start with a call to crSTART().
     crSTART( xHandle );

     for( ;; )
     {
         // Send the next character to the queue.
         crQUEUE_SEND( xHandle, xCoRoutineQueue, &cCharToTx, NO_DELAY, &xResult );

         if( xResult == pdPASS )
         {
             // The character was successfully posted to the queue.
         }
		 else
		 {
			// Could not post the character to the queue.
		 }

         // Enable the UART Tx interrupt to cause an interrupt in this
		 // hypothetical UART.  The interrupt will obtain the character
		 // from the queue and send it.
		 ENABLE_RX_INTERRUPT();

		 // Increment to the next character then block for a fixed period.
		 // cCharToTx will maintain its value across the delay as it is
		 // declared static.
		 cCharToTx++;
		 if( cCharToTx > 'x' )
		 {
			cCharToTx = 'a';
		 }
		 crDELAY( 100 );
     }

     // All co-routines must end with a call to crEND().
     crEND();
 }

 // An ISR that uses a queue to receive characters to send on a UART.
 void vUART_ISR( void )
 {
 char cCharToTx;
 portBASE_TYPE xCRWokenByPost = pdFALSE;

     while( UART_TX_REG_EMPTY() )
     {
         // Are there any characters in the queue waiting to be sent?
		 // xCRWokenByPost will automatically be set to pdTRUE if a co-routine
		 // is woken by the post - ensuring that only a single co-routine is
		 // woken no matter how many times we go around this loop.
         if( crQUEUE_RECEIVE_FROM_ISR( pxQueue, &cCharToTx, &xCRWokenByPost ) )
		 {
			 SEND_CHARACTER( cCharToTx );
		 }
     }
 }</pre>
 * \defgroup crQUEUE_RECEIVE_FROM_ISR crQUEUE_RECEIVE_FROM_ISR
 * \ingroup Tasks
 */
#define crQUEUE_RECEIVE_FROM_ISR( pxQueue, pvBuffer, pxCoRoutineWoken ) xQueueCRReceiveFromISR( pxQueue, pvBuffer, pxCoRoutineWoken )

/*
 * This function is intended for internal use by the co-routine macros only.
 * The macro nature of the co-routine implementation requires that the
 * prototype appears here.  The function should not be used by application
 * writers.
 *
 * Removes the current co-routine from its ready list and places it in the
 * appropriate delayed list.
 */
void vCoRoutineAddToDelayedList( portTickType xTicksToDelay, xList *pxEventList );

/*
 * This function is intended for internal use by the queue implementation only.
 * The function should not be used by application writers.
 *
 * Removes the highest priority co-routine from the event list and places it in
 * the pending ready list.
 */
signed portBASE_TYPE xCoRoutineRemoveFromEventList( const xList *pxEventList );

#ifdef __cplusplus
}
#endif

#endif /* CO_ROUTINE_H */