pis.c

test file nucleus source

                    if ((--i) == 0)
                        break;
                    source++;
                } while (1);
            }
            else
            {

                /* Variable-length message pipe.  */

                /* Calculate the number of bytes remaining from the write
                   pointer to the bottom of the pipe.  */
                copy_size =  destination - pipe -> pi_start;

                /* Determine if part of the message needs to be placed at the
                   bottom of the pipe area.  */
                if (copy_size < (size + i))

                    /* Compute the starting location for the message.  */
                    destination =  pipe -> pi_end - ((size + i) - copy_size);
                else

                    /* Compute the starting location for the message.  */
                    destination =  destination - (size + i);

                /* Adjust the actual pipe read pointer also.  */
                pipe -> pi_read =  destination;

                /* Place message size in first location.  */
                *((UNSIGNED *) destination) =  size;
                destination =  destination + sizeof(UNSIGNED);

                /* Check for a wrap-around condition on the pipe.  */
                if (destination >= pipe -> pi_end)

                    /* Wrap the write pointer back to the top of the pipe
                       area.  */
                    destination =  pipe -> pi_start;

                /* Decrement the number of bytes remaining for this
                   extra word of overhead.  */
                pipe -> pi_available =  pipe -> pi_available -
                                                        sizeof(UNSIGNED);

                /* Calculate the number of bytes remaining from the write
                   pointer to the bottom of the pipe.  */
                copy_size =  pipe -> pi_end - destination;

                /* Determine if the message needs to be wrapped around the
                   edge of the pipe area.  */
                if (copy_size >= (size + pad))
                {

                    /* 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 =  pipe -> pi_start;

                    /* Determine if there is anything left to copy.  */
                    if (size > copy_size)
                    {
                        /* Yes, there is something to copy.  */
                        i =  (INT) (size - copy_size);
                        do
                        {
                            *(destination++) =  *(source);
                            if ((--i) == 0)
                                break;
                            source++;
                        } while (1);
                    }
                }
                /* Decrement the number of available bytes.  */
                pipe -> pi_available =  pipe -> pi_available - pad;
            }

            /* Decrement the number of available bytes.  */
            pipe -> pi_available =  pipe -> pi_available - size;

            /* Increment the number of messages in the pipe.  */
            pipe -> pi_messages++;

#ifdef INCLUDE_PROVIEW
        _RTProf_DumpPipe(RT_PROF_SEND_TO_FRONT_OF_PIPE,pipe,RT_PROF_OK);
#endif /* INCLUDE_PROVIEW */

        }
    }

    /* Release protection against access to the pipe.  */
    TCT_Unprotect();

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

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


/*************************************************************************/
/*                                                                       */
/* FUNCTION                                                              */
/*                                                                       */
/*      PIS_Broadcast_To_Pipe                                            */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This function sends a message to all tasks waiting for a message */
/*      from the specified pipe.  If there are no tasks waiting for a    */
/*      message the service performs like a standard send request.       */
/*                                                                       */
/* CALLED BY                                                             */
/*                                                                       */
/*      Application                                                      */
/*      PISE_Broadcast_To_Pipe              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 pipe                 */
/*      TCT_Unprotect                       Release protection           */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      pipe_ptr                            Pipe 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_PIPE_FULL                        If pipe is currently full    */
/*      NU_TIMEOUT                          If timeout on service expires*/
/*      NU_PIPE_DELETED                     If pipe was deleted during   */
/*                                            suspension                 */
/*      NU_PIPE_RESET                       If pipe 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  PIS_Broadcast_To_Pipe(NU_PIPE *pipe_ptr, VOID *message,
                                        UNSIGNED size, UNSIGNED suspend)
{

R1 PI_PCB      *pipe;                       /* Pipe control block ptr    */
PI_SUSPEND      suspend_block;              /* Allocate suspension block */
PI_SUSPEND     *suspend_ptr;                /* Pointer to suspend block  */
R2 BYTE_PTR     source;                     /* Pointer to source         */
R3 BYTE_PTR     destination;                /* Pointer to destination    */
UNSIGNED        copy_size;                  /* Partial copy size         */
UNSIGNED        pad =  0;                   /* Number of pad bytes       */
R4 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 pipe pointer into internal pointer.  */
    pipe =  (PI_PCB *) pipe_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_BROADCAST_TO_PIPE_ID, (UNSIGNED) pipe,
                                        (UNSIGNED) message, (UNSIGNED) size);

#endif

    /* Initialize the status as successful.  */
    status =  NU_SUCCESS;

    /* Protect against simultaneous access to the pipe.  */
    TCT_System_Protect();

    /* Determine if an extra word of overhead needs to be added to the
       calculation.  */
    if (pipe -> pi_fixed_size)

        /* No overhead.  */
        i =  0;
    else
    {

        /* Variable messages have one additional word of overhead.  */
        i =  sizeof(UNSIGNED);

        /* Calculate the number of pad bytes necessary to keep the pipe
           write pointer on an UNSIGNED data element alignment.  */
        pad =  (((size + sizeof(UNSIGNED) - 1)/sizeof(UNSIGNED)) *
                sizeof(UNSIGNED)) - size;

        /* Insure that padding is included in the overhead.  */
        i =  i + ((INT) pad);

        /* Make special check to see if a suspension needs to be
           forced for a variable length message.  */
        if ((pipe -> pi_suspension_list) && (pipe -> pi_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 ((pipe -> pi_fifo_suspend) ||
                (suspend == NU_NO_SUSPEND) ||
                ((pipe -> pi_suspension_list) -> pi_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) pipe -> pi_available;
        }
    }

    /* Determine if there is enough room in the pipe for the message.  */
    if (pipe -> pi_available < (size + i))
    {

        /* pipe does not have room for the message.  Determine if
           suspension is required.  */
        if (suspend)
        {