evf.c

nucleus plus ARM9 source code

UNSIGNED  EVF_Event_Group_Pointers(NU_EVENT_GROUP **pointer_list,
                                                UNSIGNED maximum_pointers)
{
CS_NODE         *node_ptr;                  /* Pointer to each GCB       */
UNSIGNED         pointers;                  /* Number of pointers in list*/
NU_SUPERV_USER_VARIABLES

    /* 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

    /* Initialize the number of pointers returned.  */
    pointers =  0;

    /* Protect against access to the list of created event groups.  */
    TCT_Protect(&EVD_List_Protect);

    /* Loop until all event group pointers are in the list or until
       the maximum list size is reached.  */
    node_ptr =  EVD_Created_Event_Groups_List;
    while ((node_ptr) && (pointers < maximum_pointers))
    {

        /* Place the node into the destination list.  */
        *pointer_list++ =  (NU_EVENT_GROUP *) node_ptr;

        /* Increment the pointers variable.  */
        pointers++;

        /* Position the node pointer to the next node.  */
        node_ptr =  node_ptr -> cs_next;

        /* Determine if the pointer is at the head of the list.  */
        if (node_ptr == EVD_Created_Event_Groups_List)

            /* The list search is complete.  */
            node_ptr =  NU_NULL;
    }

    /* Release protection against access to the list of created
       event groups. */
    TCT_Unprotect();

    /* Return to user mode */
    NU_USER_MODE();

    /* Return the number of pointers in the list.  */
    return(pointers);
}


/*************************************************************************/
/*                                                                       */
/* FUNCTION                                                              */
/*                                                                       */
/*      EVF_Event_Group_Information                                      */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This function returns information about the specified event      */
/*      group. However, if the supplied event group pointer is invalid,  */
/*      the function simply returns an error status.                     */
/*                                                                       */
/* CALLED BY                                                             */
/*                                                                       */
/*      Application                                                      */
/*                                                                       */
/* CALLS                                                                 */
/*                                                                       */
/*      [TCT_Check_Stack]                   Stack checking function      */
/*      TCT_System_Protect                  Protect event group          */
/*      TCT_Unprotect                       Release protection           */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      event_group_ptr                     Pointer to the event group   */
/*      name                                Destination for the name     */
/*      event_flags                         Pointer to a variable to hold*/
/*                                            the current event flags    */
/*      tasks_waiting                       Destination for the tasks    */
/*                                            waiting count              */
/*      first_task                          Destination for the pointer  */
/*                                            to the first task waiting  */
/*                                                                       */
/* OUTPUTS                                                               */
/*                                                                       */
/*      NU_SUCCESS                          If a valid event group       */
/*                                            pointer is supplied        */
/*      NU_INVALID_GROUP                    If event group pointer is    */
/*                                            not valid                  */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*         DATE                    REMARKS                               */
/*                                                                       */
/*      03-01-1993      Created initial version 1.0                      */
/*      04-19-1993      Verified version 1.0                             */
/*      03-01-1994      Modified function interface,                     */
/*                      resulting in version 1.1                         */
/*                                                                       */
/*      03-18-1994      Verified version 1.1                             */
/*      11-18-1996      Corrected SPR220.                                */
/*                                                                       */
/*************************************************************************/
STATUS EVF_Event_Group_Information(NU_EVENT_GROUP *event_group_ptr, CHAR *name,
        UNSIGNED *event_flags, UNSIGNED *tasks_waiting, NU_TASK **first_task)
{

EV_GCB         *event_group;                /* Event control block ptr   */
INT             i;                          /* Working integer variable  */
STATUS          completion;                 /* Completion status         */
NU_SUPERV_USER_VARIABLES

    /* Switch to supervisor mode */
    NU_SUPERVISOR_MODE();

    /* Move input event group pointer into internal pointer.  */
    event_group =  (EV_GCB *) event_group_ptr;


#ifdef  NU_ENABLE_STACK_CHECK

    /* Call stack checking function to check for an overflow condition.  */
    TCT_Check_Stack();

#endif

    /* Determine if this event_group id is valid.  */
    if ((event_group != NU_NULL) && (event_group -> ev_id == EV_EVENT_ID))
    {

        /* Setup protection of the event_group.  */
        TCT_System_Protect();

        /* The event_group pointer is valid.  Reflect this in the completion
           status and fill in the actual information.  */
        completion =  NU_SUCCESS;

        /* Copy the event_group's name.  */
        for (i = 0; i < NU_MAX_NAME; i++)
            *name++ =  event_group -> ev_name[i];

        /* Return the current event flags.  */
        *event_flags =  event_group -> ev_current_events;

        /* Retrieve the number of tasks waiting and the pointer to the
           first task waiting.  */
        *tasks_waiting =  event_group -> ev_tasks_waiting;
        if (event_group -> ev_suspension_list)

            /* There is a task waiting.  */
            *first_task =  (NU_TASK *)
                (event_group -> ev_suspension_list) -> ev_suspended_task;
        else

            /* There are no tasks waiting.  */
            *first_task =  NU_NULL;

        /* Release protection of the event group.  */
        TCT_Unprotect();
    }
    else

        /* Indicate that the event group pointer is invalid.   */
        completion =  NU_INVALID_GROUP;

    /* Return to user mode */
    NU_USER_MODE();

    /* Return the appropriate completion status.  */
    return(completion);
}