+
−/*************************************************************************/
+
−/*                                                                       */
+
−/*               Copyright Mentor Graphics Corporation 2002              */
+
−/*                         All Rights Reserved.                          */
+
−/*                                                                       */
+
−/* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS  */
+
−/* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS   */
+
−/* SUBJECT TO LICENSE TERMS.                                             */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FILE NAME                                               VERSION       */
+
−/*                                                                       */
+
−/*      quc.c                                          Nucleus PLUS 1.14 */
+
−/*                                                                       */
+
−/* COMPONENT                                                             */
+
−/*                                                                       */
+
−/*      QU - Queue Management                                            */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This file contains the core routines for the Queue management    */
+
−/*      component.                                                       */
+
−/*                                                                       */
+
−/* DATA STRUCTURES                                                       */
+
−/*                                                                       */
+
−/*      None                                                             */
+
−/*                                                                       */
+
−/* FUNCTIONS                                                             */
+
−/*                                                                       */
+
−/*      QUC_Create_Queue                    Create a message queue       */
+
−/*      QUC_Delete_Queue                    Delete a message queue       */
+
−/*      QUC_Send_To_Queue                   Send message to a queue      */
+
−/*      QUC_Receive_From_Queue              Receive a message from queue */
+
−/*      QUC_Cleanup                         Cleanup on timeout or a      */
+
−/*                                            terminate condition        */
+
−/*                                                                       */
+
−/* DEPENDENCIES                                                          */
+
−/*                                                                       */
+
−/*      cs_extr.h                           Common Service functions     */
+
−/*      tc_extr.h                           Thread Control functions     */
+
−/*      qu_extr.h                           Queue functions              */
+
−/*      hi_extr.h                           History functions            */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*         DATE                    REMARKS                               */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*      08-09-1993      Corrected pointer retrieval                      */
+
−/*                      loop, resulting in version 1.0a                  */
+
−/*      08-09-1993      Verified version 1.0a                            */
+
−/*      11-01-1993      Corrected a problem with fixed-                  */
+
−/*                      size queues of a size equal to                   */
+
−/*                      one message, resulting in                        */
+
−/*                      version 1.0b                                     */
+
−/*      11-01-1993      Verified version 1.0b                            */
+
−/*      03-01-1994      Moved non-core functions into                    */
+
−/*                      supplemental files, changed                      */
+
−/*                      function interfaces to match                     */
+
−/*                      those in prototype, added                        */
+
−/*                      register options, changed                        */
+
−/*                      protection logic to reduce                       */
+
−/*                      overhead, corrected bug in                       */
+
−/*                      queue reset, optimized item                      */
+
−/*                      copy loops, resulting in                         */
+
−/*                      version 1.1                                      */
+
−/*                                                                       */
+
−/*      03-18-1994      Verified version 1.1                             */
+
−/*      04-17-1996      updated to version 1.2                           */
+
−/*      01-28-1998      Corrected SPR412 resulting in                    */
+
−/*                      version 1.2a.                                    */
+
−/*      03-24-1998      Released version 1.3                             */
+
−/*      03-26-1999      Released 1.11m (new release                      */
+
−/*                        numbering scheme)                              */
+
−/*      04-17-2002      Released version 1.13m                           */
+
−/*      11-07-2002      Released version 1.14                            */
+
−/*************************************************************************/
+
−#define         NU_SOURCE_FILE
+
−
+
−
+
−#include        "cs_extr.h"                 /* Common service functions  */
+
−#include        "tc_extr.h"                 /* Thread control functions  */
+
−#include        "qu_extr.h"                 /* Queue functions           */
+
−#include        "hi_extr.h"                 /* History functions         */
+
−
+
−
+
−/* Define external inner-component global data references.  */
+
−
+
−extern CS_NODE         *QUD_Created_Queues_List;
+
−extern UNSIGNED         QUD_Total_Queues;
+
−extern TC_PROTECT       QUD_List_Protect;
+
−
+
−
+
−/* Define internal component function prototypes.  */
+
−
+
−VOID    QUC_Cleanup(VOID *information);
+
−
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FUNCTION                                                              */
+
−/*                                                                       */
+
−/*      QUC_Create_Queue                                                 */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This function creates a queue and then places it on the list     */
+
−/*      of created queues.                                               */
+
−/*                                                                       */
+
−/* CALLED BY                                                             */
+
−/*                                                                       */
+
−/*      Application                                                      */
+
−/*      QUCE_Create_Queue                   Error checking shell         */
+
−/*                                                                       */
+
−/* CALLS                                                                 */
+
−/*                                                                       */
+
−/*      CSC_Place_On_List                   Add node to linked-list      */
+
−/*      [HIC_Make_History_Entry]            Make entry in history log    */
+
−/*      [TCT_Check_Stack]                   Stack checking function      */
+
−/*      TCT_Protect                         Protect created list         */
+
−/*      TCT_Unprotect                       Un-protect data structure    */
+
−/*                                                                       */
+
−/* INPUTS                                                                */
+
−/*                                                                       */
+
−/*      queue_ptr                           Queue control block pointer  */
+
−/*      name                                Queue name                   */
+
−/*      start_address                       Starting address of actual   */
+
−/*                                            queue area                 */
+
−/*      queue_size                          Total size of queue          */
+
−/*      message_type                        Type of message supported by */
+
−/*                                            the queue (fixed/variable) */
+
−/*      message_size                        Size of message.  Variable   */
+
−/*                                            message-length queues, this*/
+
−/*                                            represents the maximum size*/
+
−/*      suspend_type                        Suspension type              */
+
−/*                                                                       */
+
−/* OUTPUTS                                                               */
+
−/*                                                                       */
+
−/*      NU_SUCCESS                                                       */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*         DATE                    REMARKS                               */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*      03-01-1994      Changed function interfaces to                   */
+
−/*                      match those in prototype,                        */
+
−/*                      added register options,                          */
+
−/*                      resulting in version 1.1                         */
+
−/*                                                                       */
+
−/*      03-18-1994      Verified version 1.1                             */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−STATUS  QUC_Create_Queue(NU_QUEUE *queue_ptr, CHAR *name,
+
−                      VOID *start_address, UNSIGNED queue_size,
+
−                      OPTION message_type, UNSIGNED message_size,
+
−                      OPTION suspend_type)
+
−{
+
−
+
−R1 QU_QCB      *queue;                      /* Queue control block ptr   */
+
−INT             i;                          /* Working index variable    */
+
−NU_SUPERV_USER_VARIABLES
+
−
+
−    /* Switch to supervisor mode */
+
−    NU_SUPERVISOR_MODE();
+
−
+
−    /* Move input queue pointer into internal pointer.  */
+
−    queue =  (QU_QCB *) queue_ptr;
+
−
+
−
+
−#ifdef  NU_ENABLE_STACK_CHECK
+
−
+
−    /* Call stack checking function to check for an overflow condition.  */
+
−    TCT_Check_Stack();
+
−
+
−#endif
+
−
+
−#ifdef  NU_ENABLE_HISTORY
+
−
+
−    /* Make an entry that corresponds to this function in the system history
+
−       log.  */
+
−    HIC_Make_History_Entry(NU_CREATE_QUEUE_ID, (UNSIGNED) queue,
+
−                                (UNSIGNED) name, (UNSIGNED) start_address);
+
−
+
−#endif
+
−
+
−    /* First, clear the queue ID just in case it is an old Queue
+
−       Control Block.  */
+
−    queue -> qu_id =             0;
+
−
+
−    /* Fill in the queue name.  */
+
−    for (i = 0; i < NU_MAX_NAME; i++)
+
−        queue -> qu_name[i] =  name[i];
+
−
+
−    /* Setup the queue suspension type.  */
+
−    if (suspend_type == NU_FIFO)
+
−
+
−        /* FIFO suspension is selected, setup the flag accordingly.  */
+
−        queue -> qu_fifo_suspend =  NU_TRUE;
+
−
+
−    else
+
−
+
−        /* Priority suspension is selected.  */
+
−        queue -> qu_fifo_suspend =  NU_FALSE;
+
−
+
−    /* Setup the queue message type.  */
+
−    if (message_type == NU_FIXED_SIZE)
+
−
+
−        /* Fixed-size messages are required.  */
+
−        queue -> qu_fixed_size =  NU_TRUE;
+
−    else
+
−
+
−        /* Variable-size messages are required.  */
+
−        queue -> qu_fixed_size =  NU_FALSE;
+
−
+
−    /* Setup the message size.  */
+
−    queue -> qu_message_size =  message_size;
+
−
+
−    /* Clear the messages counter.   */
+
−    queue -> qu_messages =  0;
+
−
+
−    /* Setup the actual queue parameters.  */
+
−    queue -> qu_queue_size =    queue_size;
+
−
+
−    /* If the queue supports fixed-size messages, make sure that the queue
+
−       size is an even multiple of the message size.  */
+
−    if (queue -> qu_fixed_size)
+
−
+
−        /* Adjust the area of the queue being used.  */
+
−        queue_size =  (queue_size / message_size) * message_size;
+
−
+
−    queue -> qu_available =     queue_size;
+
−    queue -> qu_start =         (UNSIGNED *) start_address;
+
−    queue -> qu_end =           queue -> qu_start + queue_size;
+
−    queue -> qu_read =          (UNSIGNED *) start_address;
+
−    queue -> qu_write =         (UNSIGNED *) start_address;
+
−
+
−    /* Clear the suspension list pointer.  */
+
−    queue -> qu_suspension_list =  NU_NULL;
+
−
+
−    /* Clear the number of tasks waiting on the queue counter.  */
+
−    queue -> qu_tasks_waiting =  0;
+
−
+
−    /* Clear the urgent message list pointer.  */
+
−    queue -> qu_urgent_list =  NU_NULL;
+
−
+
−    /* Initialize link pointers.  */
+
−    queue -> qu_created.cs_previous =    NU_NULL;
+
−    queue -> qu_created.cs_next =        NU_NULL;
+
−
+
−    /* Protect against access to the list of created queues.  */
+
−    TCT_Protect(&QUD_List_Protect);
+
−
+
−    /* At this point the queue is completely built.  The ID can now be
+
−       set and it can be linked into the created queue list.  */
+
−    queue -> qu_id =                     QU_QUEUE_ID;
+
−
+
−    /* Link the queue into the list of created queues and increment the
+
−       total number of queues in the system.  */
+
−    CSC_Place_On_List(&QUD_Created_Queues_List, &(queue -> qu_created));
+
−    QUD_Total_Queues++;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−    _RTProf_DumpQueue(RT_PROF_CREATE_QUEUE,queue,RT_PROF_OK);
+
−#endif
+
−
+
−    /* Release protection against access to the list of created queues.  */
+
−    TCT_Unprotect();
+
−
+
−    /* Return to user mode */
+
−    NU_USER_MODE();
+
−
+
−    /* Return successful completion.  */
+
−    return(NU_SUCCESS);
+
−}
+
−
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FUNCTION                                                              */
+
−/*                                                                       */
+
−/*      QUC_Delete_Queue                                                 */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This function deletes a queue and removes it from the list of    */
+
−/*      created queues.  All tasks suspended on the queue are            */
+
−/*      resumed.  Note that this function does not free the memory       */
+
−/*      associated with the queue.                                       */
+
−/*                                                                       */
+
−/* CALLED BY                                                             */
+
−/*                                                                       */
+
−/*      Application                                                      */
+
−/*      QUCE_Delete_Queue                   Error checking shell         */
+
−/*                                                                       */
+
−/* CALLS                                                                 */
+
−/*                                                                       */
+
−/*      CSC_Remove_From_List                Remove node from list        */
+
−/*      [HIC_Make_History_Entry]            Make entry in history log    */
+
−/*      TCC_Resume_Task                     Resume a suspended task      */
+
−/*      [TCT_Check_Stack]                   Stack checking function      */
+
−/*      TCT_Control_To_System               Transfer control to system   */
+
−/*      TCT_Protect                         Protect created list         */
+
−/*      TCT_Set_Current_Protect             Setup current protect pointer*/
+
−/*      TCT_System_Protect                  Protect against system access*/
+
−/*      TCT_System_Unprotect                Release system protection    */
+
−/*      TCT_Unprotect                       Release protection           */
+
−/*                                                                       */
+
−/* INPUTS                                                                */
+
−/*                                                                       */
+
−/*      queue_ptr                           Queue control block pointer  */
+
−/*                                                                       */
+
−/* OUTPUTS                                                               */
+
−/*                                                                       */
+
−/*      NU_SUCCESS                                                       */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*        DATE                    REMARKS                                */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*      03-01-1994      Changed function interfaces to                   */
+
−/*                      match those in prototype,                        */
+
−/*                      added register options, changed                  */
+
−/*                      protection logic to reduce                       */
+
−/*                      overhead, resulting in                           */
+
−/*                      version 1.1                                      */
+
−/*                                                                       */
+
−/*      03-18-1994      Verified version 1.1                             */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−STATUS  QUC_Delete_Queue(NU_QUEUE *queue_ptr)
+
−{
+
−
+
−R1 QU_QCB      *queue;                      /* Queue control block ptr   */
+
−QU_SUSPEND     *suspend_ptr;                /* Suspend block pointer     */
+
−QU_SUSPEND     *next_ptr;                   /* Next suspend block pointer*/
+
−STATUS          preempt;                    /* Status for resume call    */
+
−NU_SUPERV_USER_VARIABLES
+
−
+
−    /* Move input queue pointer into internal pointer.  */
+
−    queue =  (QU_QCB *) queue_ptr;
+
−
+
−    /* Switch to supervisor mode */
+
−    NU_SUPERVISOR_MODE();
+
−
+
−#ifdef  NU_ENABLE_STACK_CHECK
+
−
+
−    /* Call stack checking function to check for an overflow condition.  */
+
−    TCT_Check_Stack();
+
−
+
−#endif
+
−
+
−#ifdef  NU_ENABLE_HISTORY
+
−
+
−    /* Make an entry that corresponds to this function in the system history
+
−       log.  */
+
−    HIC_Make_History_Entry(NU_DELETE_QUEUE_ID, (UNSIGNED) queue,
+
−                                        (UNSIGNED) 0, (UNSIGNED) 0);
+
−
+
−#endif
+
−
+
−    /* Protect against access to the queue.  */
+
−    TCT_System_Protect();
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−    _RTProf_DumpQueue(RT_PROF_DELETE_QUEUE,queue,RT_PROF_OK);
+
−#endif
+
−
+
−    /* Clear the queue ID.  */
+
−    queue -> qu_id =  0;
+
−
+
−    /* Release protection.  */
+
−    TCT_Unprotect();
+
−
+
−    /* Protect against access to the list of created queues.  */
+
−    TCT_Protect(&QUD_List_Protect);
+
−
+
−    /* Remove the queue from the list of created queues.  */
+
−    CSC_Remove_From_List(&QUD_Created_Queues_List, &(queue -> qu_created));
+
−
+
−    /* Decrement the total number of created queues.  */
+
−    QUD_Total_Queues--;
+
−
+
−    /* Pickup the suspended task pointer list.  */
+
−    suspend_ptr =  queue -> qu_suspension_list;
+
−
+
−    /* Walk the chain task(s) currently suspended on the queue.  */
+
−    preempt =  0;
+
−    while (suspend_ptr)
+
−    {
+
−
+
−        /* Protect against system access.  */
+
−        TCT_System_Protect();
+
−
+
−        /* Resume the suspended task.  Insure that the status returned is
+
−           NU_QUEUE_DELETED.  */
+
−        suspend_ptr -> qu_return_status =  NU_QUEUE_DELETED;
+
−
+
−        /* Point to the next suspend structure in the link.  */
+
−        next_ptr =  (QU_SUSPEND *) (suspend_ptr -> qu_suspend_link.cs_next);
+
−
+
−        /* Resume the specified task.  */
+
−        preempt =  preempt |
+
−            TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task,
+
−                                                NU_QUEUE_SUSPEND);
+
−
+
−        /* Determine if the next is the same as the head pointer.  */
+
−        if (next_ptr == queue -> qu_suspension_list)
+
−
+
−            /* Clear the suspension pointer to signal the end of the list
+
−               traversal.  */
+
−            suspend_ptr =  NU_NULL;
+
−        else
+
−
+
−            /* Position suspend pointer to the next pointer.  */
+
−            suspend_ptr =  next_ptr;
+
−
+
−        /* Modify current protection.  */
+
−        TCT_Set_Current_Protect(&QUD_List_Protect);
+
−
+
−        /* Clear the system protection.  */
+
−        TCT_System_Unprotect();
+
−    }
+
−
+
−    /* Pickup the urgent message suspension list.  */
+
−    suspend_ptr =  queue -> qu_urgent_list;
+
−
+
−    /* Walk the chain task(s) currently suspended on the queue.  */
+
−    while (suspend_ptr)
+
−    {
+
−
+
−        /* Protect against system access.  */
+
−        TCT_System_Protect();
+
−
+
−        /* Resume the suspended task.  Insure that the status returned is
+
−           NU_QUEUE_DELETED.  */
+
−        suspend_ptr -> qu_return_status =  NU_QUEUE_DELETED;
+
−
+
−        /* Point to the next suspend structure in the link.  */
+
−        next_ptr =  (QU_SUSPEND *) (suspend_ptr -> qu_suspend_link.cs_next);
+
−
+
−        /* Resume the specified task.  */
+
−        preempt =  preempt |
+
−                TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task,
+
−                                                NU_QUEUE_SUSPEND);
+
−
+
−        /* Determine if the next is the same as the head pointer.  */
+
−        if (next_ptr == queue -> qu_urgent_list)
+
−
+
−            /* Clear the suspension pointer to signal the end of the list
+
−               traversal.  */
+
−            suspend_ptr =  NU_NULL;
+
−        else
+
−
+
−            /* Position to the next suspend block in the list.  */
+
−            suspend_ptr =  next_ptr;
+
−
+
−        /* Modify current protection.  */
+
−        TCT_Set_Current_Protect(&QUD_List_Protect);
+
−
+
−        /* Clear the system protection.  */
+
−        TCT_System_Unprotect();
+
−    }
+
−
+
−    /* Determine if preemption needs to occur.  */
+
−    if (preempt)
+
−
+
−        /* Transfer control to system to facilitate preemption.  */
+
−        TCT_Control_To_System();
+
−
+
−    /* Release protection against access to the list of created queues.  */
+
−    TCT_Unprotect();
+
−
+
−    /* Return to user mode */
+
−    NU_USER_MODE();
+
−
+
−    /* Return a successful completion.  */
+
−    return(NU_SUCCESS);
+
−}
+
−
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FUNCTION                                                              */
+
−/*                                                                       */
+
−/*      QUC_Send_To_Queue                                                */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This function sends a message to the specified queue.  The       */
+
−/*      message length is determined by the caller.  If there are one    */
+
−/*      or more tasks suspended on the queue for a message, the message  */
+
−/*      is copied into the message area of the first waiting task.  If   */
+
−/*      the task's request is satisfied, it is resumed.  Otherwise, if   */
+
−/*      the queue cannot hold the message, suspension of the calling     */
+
−/*      task is an option of the caller.                                 */
+
−/*                                                                       */
+
−/* CALLED BY                                                             */
+
−/*                                                                       */
+
−/*      Application                                                      */
+
−/*      QUCE_Send_To_Queue                  Error checking shell         */
+
−/*                                                                       */
+
−/* CALLS                                                                 */
+
−/*                                                                       */
+
−/*      CSC_Place_On_List                   Place on suspend list        */
+
−/*      CSC_Priority_Place_On_List          Place on priority list       */
+
−/*      CSC_Remove_From_List                Remove from suspend list     */
+
−/*      [HIC_Make_History_Entry]            Make entry in history log    */
+
−/*      TCC_Resume_Task                     Resume a suspended task      */
+
−/*      TCC_Suspend_Task                    Suspend calling task         */
+
−/*      TCC_Task_Priority                   Pickup task's priority       */
+
−/*      [TCT_Check_Stack]                   Stack checking function      */
+
−/*      TCT_Control_To_System               Transfer control to system   */
+
−/*      TCT_Current_Thread                  Pickup current thread pointer*/
+
−/*      TCT_System_Protect                  Protect queue                */
+
−/*      TCT_Unprotect                       Release protection           */
+
−/*                                                                       */
+
−/* INPUTS                                                                */
+
−/*                                                                       */
+
−/*      queue_ptr                           Queue control block pointer  */
+
−/*      message                             Pointer to message to send   */
+
−/*      size                                Size of message to send      */
+
−/*      suspend                             Suspension option if full    */
+
−/*                                                                       */
+
−/* OUTPUTS                                                               */
+
−/*                                                                       */
+
−/*      NU_SUCCESS                          If service is successful     */
+
−/*      NU_QUEUE_FULL                       If queue is currently full   */
+
−/*      NU_TIMEOUT                          If timeout on service expires*/
+
−/*      NU_QUEUE_DELETED                    If queue was deleted during  */
+
−/*                                            suspension                 */
+
−/*      NU_QUEUE_RESET                      If queue was reset during    */
+
−/*                                            suspension                 */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*        DATE                    REMARKS                                */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*      03-01-1994      Changed function interfaces to                   */
+
−/*                      match those in prototype,                        */
+
−/*                      added register options, changed                  */
+
−/*                      protection logic to reduce                       */
+
−/*                      overhead, optimized copy loop,                   */
+
−/*                      resulting in version 1.1                         */
+
−/*                                                                       */
+
−/*      03-18-1994      Verified version 1.1                             */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−STATUS  QUC_Send_To_Queue(NU_QUEUE *queue_ptr, VOID *message, UNSIGNED size,
+
−                                                        UNSIGNED suspend)
+
−{
+
−
+
−R1 QU_QCB      *queue;                      /* Queue control block ptr   */
+
−QU_SUSPEND      suspend_block;              /* Allocate suspension block */
+
−QU_SUSPEND     *suspend_ptr;                /* Pointer to suspend block  */
+
−R3 UNSIGNED_PTR source;                     /* Pointer to source         */
+
−R4 UNSIGNED_PTR destination;                /* Pointer to destination    */
+
−UNSIGNED        copy_size;                  /* Partial copy size         */
+
−R2 INT          i;                          /* Working counter           */
+
−TC_TCB         *task;                       /* Task pointer              */
+
−STATUS          preempt;                    /* Preempt flag              */
+
−STATUS          status;                     /* Completion status         */
+
−NU_SUPERV_USER_VARIABLES
+
−
+
−    /* Switch to supervisor mode */
+
−    NU_SUPERVISOR_MODE();
+
−
+
−    /* Move input queue pointer into internal pointer.  */
+
−    queue =  (QU_QCB *) queue_ptr;
+
−
+
−
+
−#ifdef  NU_ENABLE_STACK_CHECK
+
−
+
−    /* Call stack checking function to check for an overflow condition.  */
+
−    TCT_Check_Stack();
+
−
+
−#endif
+
−
+
−#ifdef  NU_ENABLE_HISTORY
+
−
+
−    /* Make an entry that corresponds to this function in the system history
+
−       log.  */
+
−    HIC_Make_History_Entry(NU_SEND_TO_QUEUE_ID, (UNSIGNED) queue,
+
−                                        (UNSIGNED) message, (UNSIGNED) size);
+
−
+
−#endif
+
−
+
−    /* Initialize the status as successful.  */
+
−    status =  NU_SUCCESS;
+
−
+
−    /* Protect against simultaneous access to the queue.  */
+
−    TCT_System_Protect();
+
−
+
−    /* Determine if an extra word of overhead needs to be added to the
+
−       calculation.  */
+
−    if (queue -> qu_fixed_size)
+
−
+
−        /* No overhead.  */
+
−        i =  0;
+
−    else
+
−    {
+
−        /* Variable messages have one additional word of overhead.  */
+
−        i =  1;
+
−
+
−        /* Make special check to see if a suspension needs to be
+
−           forced for a variable length message.  */
+
−        if ((queue -> qu_suspension_list) && (queue -> qu_messages))
+
−        {
+
−
+
−            /* Pickup task control block pointer.  */
+
−            task =  (TC_TCB *) TCT_Current_Thread();
+
−
+
−            /* Now we know that there are other task(s) are suspended trying
+
−               to send a variable length message.  Determine whether or not
+
−               a suspension should be forced.  */
+
−            if ((queue -> qu_fifo_suspend) ||
+
−                (suspend == NU_NO_SUSPEND) ||
+
−                ((queue -> qu_suspension_list) -> qu_suspend_link.cs_priority <=
+
−                                                    TCC_Task_Priority(task)))
+
−
+
−                /* Bump the computed size to avoid placing the new variable
+
−                   length message ahead of the suspended tasks.  */
+
−                i =  (INT) queue -> qu_available;
+
−        }
+
−    }
+
−
+
−    /* Determine if there is enough room in the queue for the message.  The
+
−       extra logic is to prevent a variable-length message from sn*/
+
−    if (queue -> qu_available < (size + i))
+
−    {
+
−
+
−        /* Queue does not have room for the message.  Determine if
+
−           suspension is required.  */
+
−        if (suspend)
+
−        {
+
−
+
−            /* Suspension is requested.   */
+
−
+
−            /* Increment the number of tasks waiting.  */
+
−            queue -> qu_tasks_waiting++;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−            _RTProf_DumpQueue(RT_PROF_SEND_TO_QUEUE,queue,RT_PROF_WAIT);
+
−#endif
+
−
+
−            /* Setup the suspend block and suspend the calling task.  */
+
−            suspend_ptr =  &suspend_block;
+
−            suspend_ptr -> qu_queue =                    queue;
+
−            suspend_ptr -> qu_suspend_link.cs_next =     NU_NULL;
+
−            suspend_ptr -> qu_suspend_link.cs_previous = NU_NULL;
+
−            suspend_ptr -> qu_message_area =             (UNSIGNED_PTR) message;
+
−            suspend_ptr -> qu_message_size =             size;
+
−            task =                            (TC_TCB *) TCT_Current_Thread();
+
−            suspend_ptr -> qu_suspended_task =           task;
+
−
+
−            /* Determine if priority or FIFO suspension is associated with the
+
−               queue.  */
+
−            if (queue -> qu_fifo_suspend)
+
−            {
+
−
+
−                /* FIFO suspension is required.  Link the suspend block into
+
−                   the list of suspended tasks on this queue.  */
+
−                CSC_Place_On_List((CS_NODE **) &(queue -> qu_suspension_list),
+
−                                        &(suspend_ptr -> qu_suspend_link));
+
−            }
+
−            else
+
−            {
+
−
+
−                /* Get the priority of the current thread so the suspend block
+
−                   can be placed in the appropriate place.  */
+
−                suspend_ptr -> qu_suspend_link.cs_priority =
+
−                                                 TCC_Task_Priority(task);
+
−
+
−                CSC_Priority_Place_On_List((CS_NODE **)
+
−                                &(queue -> qu_suspension_list),
+
−                                        &(suspend_ptr -> qu_suspend_link));
+
−            }
+
−
+
−            /* Finally, suspend the calling task. Note that the suspension call
+
−               automatically clears the protection on the queue.  */
+
−            TCC_Suspend_Task((NU_TASK *) task, NU_QUEUE_SUSPEND,
+
−                                        QUC_Cleanup, suspend_ptr, suspend);
+
−
+
−            /* Pickup the return status.  */
+
−            status =  suspend_ptr -> qu_return_status;
+
−        }
+
−        else
+
−        {
+
−
+
−            /* Return a status of NU_QUEUE_FULL because there is no
+
−               room in the queue for the message.  */
+
−            status =  NU_QUEUE_FULL;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−            _RTProf_DumpQueue(RT_PROF_SEND_TO_QUEUE,queue,RT_PROF_FAIL);
+
−#endif
+
−
+
−        }
+
−    }
+
−    else
+
−    {
+
−
+
−        /* Determine if a task is waiting on an empty queue.  */
+
−        if ((queue -> qu_suspension_list) && (queue -> qu_messages == 0))
+
−        {
+
−
+
−            /* Task is waiting on an empty queue for a message.  */
+
−
+
−            /* Decrement the number of tasks waiting on queue.  */
+
−            queue -> qu_tasks_waiting--;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−        _RTProf_DumpQueue(RT_PROF_SEND_TO_QUEUE,queue,RT_PROF_OK);
+
−#endif
+
−
+
−            /* Remove the first suspended block from the list.  */
+
−            suspend_ptr =  queue -> qu_suspension_list;
+
−            CSC_Remove_From_List((CS_NODE **) &(queue -> qu_suspension_list),
+
−                                          &(suspend_ptr -> qu_suspend_link));
+
−
+
−            /* Setup the source and destination pointers.  */
+
−            source =       (UNSIGNED_PTR) message;
+
−            destination =  suspend_ptr -> qu_message_area;
+
−
+
−            /* Initialize the return status.  */
+
−            suspend_ptr -> qu_return_status =  NU_SUCCESS;
+
−
+
−            /* Loop to actually copy the message.  */
+
−            i = (INT) size;
+
−            do
+
−            {
+
−                *(destination++) =  *(source);
+
−                if ((--i) == 0)
+
−                    break;
+
−                source++;
+
−            } while (1);
+
−
+
−            /* Return the size of the message copied.  */
+
−            suspend_ptr -> qu_actual_size =  size;
+
−
+
−            /* Wakeup the waiting task and check for preemption.  */
+
−            preempt =
+
−                TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task,
+
−                                                     NU_QUEUE_SUSPEND);
+
−
+
−            /* Determine if preemption needs to take place. */
+
−            if (preempt)
+
−
+
−                 /* Transfer control to the system if the resumed task function
+
−                   detects a preemption condition.  */
+
−                TCT_Control_To_System();
+
−        }
+
−        else
+
−        {
+
−
+
−            /* There is enough room in the queue and no task is waiting.  */
+
−
+
−            /* Setup the source pointer.  */
+
−            source =       (UNSIGNED_PTR) message;
+
−            destination =  queue -> qu_write;
+
−
+
−            /* Process according to the type of message supported.  */
+
−            if (queue -> qu_fixed_size)
+
−            {
+
−
+
−                /* Fixed-size messages are supported by this queue.  */
+
−
+
−                /* Loop to copy the message into the queue area.  */
+
−                i =  (INT) size;
+
−                do
+
−                {
+
−                    *(destination++) =  *(source);
+
−                    if ((--i) == 0)
+
−                        break;
+
−                    source++;
+
−                } while (1);
+
−            }
+
−            else
+
−            {
+
−
+
−                /* Variable-size messages are supported.  Processing must
+
−                   check for queue wrap-around conditions.  */
+
−
+
−                /* Place message size in first location.  */
+
−                *(destination++) =  size;
+
−
+
−                /* Check for a wrap-around condition on the queue.  */
+
−                if (destination >= queue -> qu_end)
+
−
+
−                    /* Wrap the write pointer back to the top of the queue
+
−                       area.  */
+
−                    destination =  queue -> qu_start;
+
−
+
−                /* Decrement the number of words remaining by 1 for this
+
−                   extra word of overhead.  */
+
−                queue -> qu_available--;
+
−
+
−                /* Calculate the number of words remaining from the write
+
−                   pointer to the bottom of the queue.  */
+
−                copy_size =  queue -> qu_end - destination;
+
−
+
−                /* Determine if the message needs to be wrapped around the
+
−                   edge of the queue area.  */
+
−                if (copy_size >= size)
+
−                {
+
−
+
−                    /* Copy the whole message at once.  */
+
−                    i =  (INT) size;
+
−                    do
+
−                    {
+
−                        *(destination++) =  *(source);
+
−                        if ((--i) == 0)
+
−                            break;
+
−                        source++;
+
−                    } while (1);
+
−                }
+
−                else
+
−                {
+
−
+
−                    /* Copy the first half of the message.  */
+
−                    i =  (INT) copy_size;
+
−                    do
+
−                    {
+
−                        *(destination) =  *(source++);
+
−                        if ((--i) == 0)
+
−                            break;
+
−                        destination++;
+
−                    } while (1);
+
−
+
−                    /* Copy the second half of the message.  */
+
−                    destination =  queue -> qu_start;
+
−                    i =  (INT) (size - copy_size);
+
−                    do
+
−                    {
+
−                        *(destination++) =  *(source);
+
−                        if ((--i) == 0)
+
−                            break;
+
−                        source++;
+
−                    } while (1);
+
−                }
+
−            }
+
−
+
−            /* Check again for wrap-around condition on the write pointer. */
+
−            if (destination >= queue -> qu_end)
+
−
+
−                /* Move the write pointer to the top of the queue area.  */
+
−                queue -> qu_write =  queue -> qu_start;
+
−            else
+
−
+
−                /* Simply copy the last position of the destination pointer
+
−                   into the write pointer.  */
+
−                queue -> qu_write =  destination;
+
−
+
−            /* Decrement the number of available words.  */
+
−            queue -> qu_available =  queue -> qu_available - size;
+
−
+
−            /* Increment the number of messages in the queue.  */
+
−            queue -> qu_messages++;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−        _RTProf_DumpQueue(RT_PROF_SEND_TO_QUEUE,queue,RT_PROF_OK);
+
−#endif
+
−
+
−        }
+
−    }
+
−
+
−    /* Release protection against access to the queue.  */
+
−    TCT_Unprotect();
+
−
+
−    /* Return to user mode */
+
−    NU_USER_MODE();
+
−
+
−    /* Return the completion status.  */
+
−    return(status);
+
−}
+
−
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FUNCTION                                                              */
+
−/*                                                                       */
+
−/*      QUC_Receive_From_Queue                                           */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This function receives a message from the specified queue.  The  */
+
−/*      size of the message is specified by the caller.  If there is a   */
+
−/*      message currently in the queue, the message is removed from the  */
+
−/*      queue and placed in the caller's area.  Suspension is possible   */
+
−/*      if the request cannot be satisfied.                              */
+
−/*                                                                       */
+
−/* CALLED BY                                                             */
+
−/*                                                                       */
+
−/*      Application                                                      */
+
−/*      QUCE_Receive_From_Queue             Error checking shell         */
+
−/*                                                                       */
+
−/* CALLS                                                                 */
+
−/*                                                                       */
+
−/*      CSC_Place_On_List                   Place on suspend list        */
+
−/*      CSC_Priority_Place_On_List          Place on priority list       */
+
−/*      CSC_Remove_From_List                Remove from suspend list     */
+
−/*      [HIC_Make_History_Entry]            Make entry in history log    */
+
−/*      TCC_Resume_Task                     Resume a suspended task      */
+
−/*      TCC_Suspend_Task                    Suspend calling task         */
+
−/*      TCC_Task_Priority                   Pickup task's priority       */
+
−/*      [TCT_Check_Stack]                   Stack checking function      */
+
−/*      TCT_Control_To_System               Transfer control to system   */
+
−/*      TCT_Current_Thread                  Pickup current thread pointer*/
+
−/*      TCT_System_Protect                  Protect queue                */
+
−/*      TCT_Unprotect                       Release protection           */
+
−/*                                                                       */
+
−/* INPUTS                                                                */
+
−/*                                                                       */
+
−/*      queue_ptr                           Queue control block pointer  */
+
−/*      message                             Pointer to message to send   */
+
−/*      size                                Size of the message          */
+
−/*      actual_size                         Size of message received     */
+
−/*      suspend                             Suspension option if empty   */
+
−/*                                                                       */
+
−/* OUTPUTS                                                               */
+
−/*                                                                       */
+
−/*      NU_SUCCESS                          If service is successful     */
+
−/*      NU_QUEUE_EMPTY                      If queue is currently empty  */
+
−/*      NU_TIMEOUT                          If timeout on service expires*/
+
−/*      NU_QUEUE_DELETED                    If queue was deleted during  */
+
−/*                                            suspension                 */
+
−/*      NU_QUEUE_RESET                      If queue was reset during    */
+
−/*                                            suspension                 */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*         DATE                    REMARKS                               */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*      11-01-1993      Corrected a problem resuming a                   */
+
−/*                      task suspended on a full queue                   */
+
−/*                      that only has a capacity of a                    */
+
−/*                      single message, resulting in                     */
+
−/*                      version 1.0b                                     */
+
−/*      11-01-1993      Verified version 1.0b                            */
+
−/*      03-01-1994      Changed function interfaces to                   */
+
−/*                      match those in prototype,                        */
+
−/*                      added register options, changed                  */
+
−/*                      protection logic to reduce                       */
+
−/*                      overhead, optimized copy loop,                   */
+
−/*                      resulting in version 1.1                         */
+
−/*                                                                       */
+
−/*      03-18-1994      Verified version 1.1                             */
+
−/*      01-28-1998      Corrected SPR412.                                */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−STATUS  QUC_Receive_From_Queue(NU_QUEUE *queue_ptr, VOID *message,
+
−                UNSIGNED size, UNSIGNED *actual_size, UNSIGNED suspend)
+
−{
+
−
+
−R1 QU_QCB      *queue;                      /* Queue control block ptr   */
+
−QU_SUSPEND      suspend_block;              /* Allocate suspension block */
+
−QU_SUSPEND     *suspend_ptr;                /* Pointer to suspend block  */
+
−R3 UNSIGNED_PTR source;                     /* Pointer to source         */
+
−R4 UNSIGNED_PTR destination;                /* Pointer to destination    */
+
−TC_TCB         *task;                       /* Task pointer              */
+
−UNSIGNED        copy_size;                  /* Number of words to copy   */
+
−R2 INT          i;                          /* Working counter           */
+
−STATUS          preempt;                    /* Preemption flag           */
+
−STATUS          status;                     /* Completion status         */
+
−NU_SUPERV_USER_VARIABLES
+
−
+
−
+
−    /* Move input queue pointer into internal pointer.  */
+
−    queue =  (QU_QCB *) queue_ptr;
+
−
+
−    /* Switch to supervisor mode */
+
−    NU_SUPERVISOR_MODE();
+
−
+
−#ifdef  NU_ENABLE_STACK_CHECK
+
−
+
−    /* Call stack checking function to check for an overflow condition.  */
+
−    TCT_Check_Stack();
+
−
+
−#endif
+
−
+
−#ifdef  NU_ENABLE_HISTORY
+
−
+
−    /* Make an entry that corresponds to this function in the system history
+
−       log.  */
+
−    HIC_Make_History_Entry(NU_RECEIVE_FROM_QUEUE_ID, (UNSIGNED) queue,
+
−                                        (UNSIGNED) message, (UNSIGNED) size);
+
−
+
−#endif
+
−
+
−    /* Initialize the status as successful.  */
+
−    status =  NU_SUCCESS;
+
−
+
−    /* Protect against simultaneous access to the queue.  */
+
−    TCT_System_Protect();
+
−
+
−    /* Determine if an urgent message request is currently suspended.  */
+
−    if (queue -> qu_urgent_list)
+
−    {
+
−
+
−        /* If so, copy the message from the suspended request block and
+
−           resume the associated task.  */
+
−
+
−        /* Decrement the number of tasks waiting on queue.  */
+
−        queue -> qu_tasks_waiting--;
+
−
+
−        /* Remove the first suspended block from the list.  */
+
−        suspend_ptr =  queue -> qu_urgent_list;
+
−        CSC_Remove_From_List((CS_NODE **) &(queue -> qu_urgent_list),
+
−                                          &(suspend_ptr -> qu_suspend_link));
+
−
+
−        /* Setup the source and destination pointers.  */
+
−        destination =   (UNSIGNED_PTR) message;
+
−        source =        suspend_ptr -> qu_message_area;
+
−
+
−        /* Initialize the return status.  */
+
−        suspend_ptr -> qu_return_status =  NU_SUCCESS;
+
−
+
−        /* Loop to actually copy the message.  */
+
−        i =  (INT) suspend_ptr -> qu_message_size;
+
−        do
+
−        {
+
−            *(destination++) =  *(source);
+
−            if ((--i) == 0)
+
−                break;
+
−            source++;
+
−        } while (1);
+
−
+
−        /* Return the size of the message copied.  */
+
−        *actual_size =  suspend_ptr -> qu_message_size;
+
−
+
−        /* Wakeup the waiting task and check for preemption.  */
+
−        preempt =
+
−            TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task,
+
−                                                     NU_QUEUE_SUSPEND);
+
−
+
−        /* Determine if preemption needs to take place. */
+
−        if (preempt)
+
−
+
−             /* Transfer control to the system if the resumed task function
+
−                detects a preemption condition.  */
+
−             TCT_Control_To_System();
+
−    }
+
−
+
−    /* Determine if there are messages in the queue.  */
+
−    else if (queue -> qu_messages)
+
−    {
+
−
+
−        /* Copy message from queue into the caller's area.  */
+
−
+
−        /* Setup the source and destination pointers.  */
+
−        source =       queue -> qu_read;
+
−        destination =  (UNSIGNED_PTR) message;
+
−
+
−        /* Process according to the type of message supported by the queue. */
+
−        if (queue -> qu_fixed_size)
+
−        {
+
−
+
−            /* Queue supports fixed-size messages.  */
+
−
+
−            /* Copy the message from the queue area into the destination.  */
+
−            i =  (INT) size;
+
−            do
+
−            {
+
−                *(destination) =  *(source++);
+
−                if ((--i) == 0)
+
−                    break;
+
−                destination++;
+
−            } while (1);
+
−        }
+
−        else
+
−        {
+
−
+
−            /* Queue supports variable-size messages.  */
+
−
+
−            /* Variable length message size is actually in the queue area. */
+
−            size =  *(source++);
+
−
+
−            /* Check for a wrap-around condition on the queue.  */
+
−            if (source >= queue -> qu_end)
+
−
+
−                /* Wrap the read pointer back to the top of the queue
+
−                   area.  */
+
−                source =  queue -> qu_start;
+
−
+
−            /* Increment the number of available words in the queue.  */
+
−            queue -> qu_available++;
+
−
+
−            /* Calculate the number of words remaining from the read pointer
+
−               to the bottom of the queue.  */
+
−            copy_size =  queue -> qu_end - source;
+
−
+
−            /* Determine if the message needs to be wrapped around the
+
−               edge of the queue area.  */
+
−            if (copy_size >= size)
+
−            {
+
−
+
−                /* Copy the whole message at once.  */
+
−                i =  (INT) size;
+
−                do
+
−                {
+
−                    *(destination) =  *(source++);
+
−                    if ((--i) == 0)
+
−                        break;
+
−                    destination++;
+
−                } while (1);
+
−            }
+
−            else
+
−            {
+
−
+
−                /* Copy the first half of the message.  */
+
−                i =  (INT) copy_size;
+
−                do
+
−                {
+
−                    *(destination++) =  *(source);
+
−                    if ((--i) == 0)
+
−                        break;
+
−                    source++;
+
−                } while (1);
+
−
+
−                /* Copy the second half of the message.  */
+
−                source =  queue -> qu_start;
+
−                i =  (INT) (size - copy_size);
+
−                do
+
−                {
+
−                    *(destination) =  *(source++);
+
−                    if ((--i) == 0)
+
−                        break;
+
−                    destination++;
+
−                } while (1);
+
−            }
+
−        }
+
−
+
−        /* Check again for wrap-around condition on the read pointer. */
+
−        if (source >= queue -> qu_end)
+
−
+
−            /* Move the read pointer to the top of the queue area.  */
+
−            queue -> qu_read =  queue -> qu_start;
+
−        else
+
−
+
−            /* Move the read pointer to where the copy left off.  */
+
−            queue -> qu_read =  source;
+
−
+
−        /* Increment the number of available words.  */
+
−        queue -> qu_available =  queue -> qu_available + size;
+
−
+
−        /* Decrement the number of messages in the queue.  */
+
−        queue -> qu_messages--;
+
−
+
−        /* Return the number of words received.  */
+
−        *actual_size =  size;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−        _RTProf_DumpQueue(RT_PROF_RECEIVE_FROM_QUEUE,queue,RT_PROF_OK);
+
−#endif
+
−
+
−        /* Determine if any tasks suspended on a full queue can be woken
+
−           up.  */
+
−        if (queue -> qu_suspension_list)
+
−        {
+
−
+
−            /* Overhead of each queue message.  */
+
−            if (!queue -> qu_fixed_size)
+
−
+
−                i =  1;
+
−            else
+
−
+
−                i =  0;
+
−
+
−            /* Pickup the suspension list and examine suspension blocks
+
−               to see if the message could now fit in the queue.  */
+
−            suspend_ptr =  queue -> qu_suspension_list;
+
−            preempt =      NU_FALSE;
+
−            while ((suspend_ptr) &&
+
−              ((suspend_ptr -> qu_message_size + i) <= queue -> qu_available))
+
−            {
+
−
+
−                /* Place the suspended task's message into the queue.  */
+
−
+
−                /* Setup the source and destination pointers.  */
+
−                source =        suspend_ptr -> qu_message_area;
+
−                destination =   queue -> qu_write;
+
−                size =          suspend_ptr -> qu_message_size;
+
−
+
−                /* Process according to the type of message supported.  */
+
−                if (queue -> qu_fixed_size)
+
−                {
+
−
+
−                    /* Fixed-size messages are supported by this queue.  */
+
−
+
−                    /* Loop to copy the message into the queue area.  */
+
−                    i =  (INT) size;
+
−                    do
+
−                    {
+
−                        *(destination++) =  *(source);
+
−                        if ((--i) == 0)
+
−                            break;
+
−                        source++;
+
−                    } while (1);
+
−                }
+
−                else
+
−                {
+
−
+
−                    /* Variable-size messages are supported.  Processing must
+
−                       check for queue wrap-around conditions.  */
+
−
+
−                    /* Place message size in first location.  */
+
−                    *(destination++) =  size;
+
−
+
−                    /* Check for a wrap-around condition on the queue.  */
+
−                    if (destination >= queue -> qu_end)
+
−
+
−                        /* Wrap the write pointer back to the top of the queue
+
−                           area.  */
+
−                        destination =  queue -> qu_start;
+
−
+
−                    /* Decrement the number of words remaining by 1 for this
+
−                       extra word of overhead.  */
+
−                    queue -> qu_available--;
+
−
+
−                    /* Calculate the number of words remaining from the write
+
−                       pointer to the bottom of the queue.  */
+
−                    copy_size =  queue -> qu_end - destination;
+
−
+
−                    /* Determine if the message needs to be wrapped around the
+
−                       edge of the queue area.  */
+
−                    if (copy_size >= size)
+
−                    {
+
−
+
−                        /* Copy the whole message at once.  */
+
−                        i =  (INT) size;
+
−                        do
+
−                        {
+
−                            *(destination++) =  *(source);
+
−                            if ((--i) == 0)
+
−                                break;
+
−                            source++;
+
−                        } while(1);
+
−                    }
+
−                    else
+
−                    {
+
−
+
−                        /* Copy the first half of the message.  */
+
−                        i =  (INT) copy_size;
+
−                        do
+
−                        {
+
−                            *(destination) =  *(source++);
+
−                            if ((--i) == 0)
+
−                                break;
+
−                            destination++;
+
−                        } while (1);
+
−
+
−                        /* Copy the second half of the message.  */
+
−                        destination =  queue -> qu_start;
+
−                        i =  (INT) (size - copy_size);
+
−                        do
+
−                        {
+
−                            *(destination++) =  *(source);
+
−                            if ((--i) == 0)
+
−                                break;
+
−                            source++;
+
−                        } while (1);
+
−                    }
+
−                }
+
−
+
−                /* Check again for wrap-around condition on the write
+
−                   pointer. */
+
−                if (destination >= queue -> qu_end)
+
−
+
−                    /* Move the write pointer to the top of the queue area.  */
+
−                    queue -> qu_write =  queue -> qu_start;
+
−                else
+
−
+
−                    /* Simply copy the last position of the destination pointer
+
−                       into the write pointer.  */
+
−                    queue -> qu_write =  destination;
+
−
+
−                /* Decrement the number of available words.  */
+
−                queue -> qu_available =  queue -> qu_available - size;
+
−
+
−                /* Increment the number of messages in the queue.  */
+
−                queue -> qu_messages++;
+
−
+
−                /* Decrement the number of tasks waiting counter.  */
+
−                queue -> qu_tasks_waiting--;
+
−
+
−                /* Remove the first suspended block from the list.  */
+
−                CSC_Remove_From_List((CS_NODE **)
+
−                    &(queue -> qu_suspension_list),
+
−                                &(suspend_ptr -> qu_suspend_link));
+
−
+
−                /* Return a successful status.  */
+
−                suspend_ptr -> qu_return_status =  NU_SUCCESS;
+
−
+
−                /* Resume the suspended task.  */
+
−                preempt =  preempt |
+
−                  TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task,
+
−                                                       NU_QUEUE_SUSPEND);
+
−
+
−                /* Setup suspend pointer to the head of the list.  */
+
−                suspend_ptr =  queue -> qu_suspension_list;
+
−
+
−                /* Overhead of each queue message.  */
+
−                if (!queue -> qu_fixed_size)
+
−
+
−                    i =  1;
+
−                else
+
−
+
−                    i =  0;
+
−            }
+
−
+
−            /* Determine if a preempt condition is present.  */
+
−            if (preempt)
+
−
+
−                /* Transfer control to the system if the resumed task function
+
−                   detects a preemption condition.  */
+
−                TCT_Control_To_System();
+
−        }
+
−    }
+
−    else
+
−    {
+
−
+
−        /* Queue is empty.  Determine if the task wants to suspend.  */
+
−        if (suspend)
+
−        {
+
−
+
−            /* Increment the number of tasks waiting on the queue counter. */
+
−            queue -> qu_tasks_waiting++;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−            _RTProf_DumpQueue(RT_PROF_RECEIVE_FROM_QUEUE,queue,RT_PROF_WAIT);
+
−#endif
+
−
+
−            /* Setup the suspend block and suspend the calling task.  */
+
−            suspend_ptr =  &suspend_block;
+
−            suspend_ptr -> qu_queue =                    queue;
+
−            suspend_ptr -> qu_suspend_link.cs_next =     NU_NULL;
+
−            suspend_ptr -> qu_suspend_link.cs_previous = NU_NULL;
+
−            suspend_ptr -> qu_message_area =           (UNSIGNED_PTR) message;
+
−            suspend_ptr -> qu_message_size =             size;
+
−            task =                            (TC_TCB *) TCT_Current_Thread();
+
−            suspend_ptr -> qu_suspended_task =           task;
+
−
+
−            /* Determine if priority or FIFO suspension is associated with the
+
−               queue.  */
+
−            if (queue -> qu_fifo_suspend)
+
−            {
+
−
+
−                /* FIFO suspension is required.  Link the suspend block into
+
−                   the list of suspended tasks on this queue.  */
+
−                CSC_Place_On_List((CS_NODE **) &(queue -> qu_suspension_list),
+
−                                        &(suspend_ptr -> qu_suspend_link));
+
−            }
+
−            else
+
−            {
+
−
+
−                /* Get the priority of the current thread so the suspend block
+
−                   can be placed in the appropriate place.  */
+
−                suspend_ptr -> qu_suspend_link.cs_priority =
+
−                                                    TCC_Task_Priority(task);
+
−
+
−                CSC_Priority_Place_On_List((CS_NODE **)
+
−                            &(queue -> qu_suspension_list),
+
−                                            &(suspend_ptr -> qu_suspend_link));
+
−            }
+
−
+
−            /* Finally, suspend the calling task. Note that the suspension call
+
−               automatically clears the protection on the queue.  */
+
−            TCC_Suspend_Task((NU_TASK *) task, NU_QUEUE_SUSPEND,
+
−                                        QUC_Cleanup, suspend_ptr, suspend);
+
−
+
−            /* Pickup the status of the request.  */
+
−            status =  suspend_ptr -> qu_return_status;
+
−            *actual_size =  suspend_ptr -> qu_actual_size;
+
−        }
+
−        else
+
−        {
+
−
+
−            /* Return a status of NU_QUEUE_EMPTY because there are no
+
−               messages in the queue.  */
+
−            status =  NU_QUEUE_EMPTY;
+
−
+
−#ifdef INCLUDE_PROVIEW
+
−            _RTProf_DumpQueue(RT_PROF_RECEIVE_FROM_QUEUE,queue,RT_PROF_FAIL);
+
−#endif
+
−
+
−        }
+
−    }
+
−
+
−    /* Release protection against access to the queue.  */
+
−    TCT_Unprotect();
+
−
+
−    /* Return to user mode */
+
−    NU_USER_MODE();
+
−
+
−    /* Return the completion status.  */
+
−    return(status);
+
−}
+
−
+
−
+
−/*************************************************************************/
+
−/*                                                                       */
+
−/* FUNCTION                                                              */
+
−/*                                                                       */
+
−/*      QUC_Cleanup                                                      */
+
−/*                                                                       */
+
−/* DESCRIPTION                                                           */
+
−/*                                                                       */
+
−/*      This function is responsible for removing a suspension block     */
+
−/*      from a queue.  It is not called unless a timeout or a task       */
+
−/*      terminate is in progress.  Note that protection is already in    */
+
−/*      effect - the same protection at suspension time.  This routine   */
+
−/*      must be called from Supervisor mode in Supervisor/User mode      */
+
−/*      switching kernels.                                               */
+
−/*                                                                       */
+
−/* CALLED BY                                                             */
+
−/*                                                                       */
+
−/*      TCC_Timeout                         Task timeout                 */
+
−/*      TCC_Terminate                       Task terminate               */
+
−/*                                                                       */
+
−/* CALLS                                                                 */
+
−/*                                                                       */
+
−/*      CSC_Remove_From_List                Remove suspend block from    */
+
−/*                                            the suspension list        */
+
−/*                                                                       */
+
−/* INPUTS                                                                */
+
−/*                                                                       */
+
−/*      information                         Pointer to suspend block     */
+
−/*                                                                       */
+
−/* OUTPUTS                                                               */
+
−/*                                                                       */
+
−/*      None                                                             */
+
−/*                                                                       */
+
−/* HISTORY                                                               */
+
−/*                                                                       */
+
−/*        DATE                    REMARKS                                */
+
−/*                                                                       */
+
−/*      03-01-1993      Created initial version 1.0                      */
+
−/*      04-19-1993      Verified version 1.0                             */
+
−/*                                                                       */
+
−/*************************************************************************/
+
−VOID  QUC_Cleanup(VOID *information)
+
−{
+
−
+
−QU_SUSPEND      *suspend_ptr;               /* Suspension block pointer  */
+
−NU_SUPERV_USER_VARIABLES
+
−
+
−    /* Switch to supervisor mode */
+
−    NU_SUPERVISOR_MODE();
+
−
+
−    /* Use the information pointer as a suspend pointer.  */
+
−    suspend_ptr =  (QU_SUSPEND *) information;
+
−
+
−    /* By default, indicate that the service timed-out.  It really does not
+
−       matter if this function is called from a terminate request since
+
−       the task does not resume.  */
+
−    suspend_ptr -> qu_return_status =  NU_TIMEOUT;
+
−
+
−    /* Decrement the number of tasks waiting counter.  */
+
−    (suspend_ptr -> qu_queue) -> qu_tasks_waiting--;
+
−
+
−    /* Unlink the suspend block from the suspension list.  */
+
−    if ((suspend_ptr -> qu_queue) -> qu_urgent_list)
+
−    {
+
−       /* Unlink the suspend block from the suspension list.  */
+
−       CSC_Remove_From_List((CS_NODE **) 
+
−                   &((suspend_ptr -> qu_queue) -> qu_urgent_list), 
+
−                                   &(suspend_ptr -> qu_suspend_link));
+
−    }
+
−    else
+
−    {
+
−       /* Unlink the suspend block from the suspension list.  */
+
−       CSC_Remove_From_List((CS_NODE **) 
+
−                   &((suspend_ptr -> qu_queue) -> qu_suspension_list), 
+
−                                   &(suspend_ptr -> qu_suspend_link));
+
−    }
+
−
+
−    /* Return to user mode */
+
−    NU_USER_MODE();
+
−}
+
−
+
−
+
−
+
−
+
−
+
−