Type ASSEMBLE
Source Lines : 197
Fixes Applied : 0
Most Recent Version : Thursday, December 7, 1978
Last Fix ID : [Unmodified]

Module

       DMTEXT

Function

        THE DMTEXT  MODULE IS THE MSUP  EXTERNAL INTERRUPT
        HANDLER. DMTEXT  RECEIVES CONTROL  DIRECTLY ON  AN
        EXTERNAL  INTERRUPT AND  SAVES THE  STATUS OF  THE
        EXECUTING TASK IF ONE WAS INTERRUPTED.

Attributes

       REUSABLE, EXECUTABLE DISABLED ONLY

Operation

       IF A TASK WAS EXECUTING AT THE TIME OF THE INTERRUPT, IT IS
       SUSPENDED.  IF THERE HAVE BEEN NO REQUESTS FOR
       EXTERNAL INTERRUPT ASYNCHRONOUS EXITS, EXIT IS MADE TO
       THE DISPATCHER.  IF THERE HAVE BEEN REQUESTS MADE, THE
       EXTERNAL INTERRUPT CODE IS EXAMINED.  ONLY THE FOLLOWING
       INTERRUPT CODES ARE SERVICED, ALL OTHERS RESULT IN AN
       IMMEDIATE EXIT TO THE DISPATCHER:

       X'1004' - CLOCK COMPARATOR

       THE QUEUE IS SCANNED TO FIND THE ASYNCHRONOUS QUEUE
       ELEMENT WHICH CORRESPONDS TO THIS INTERRUPT.

       FOR CLOCK COMPARATOR INTERRUPTS, THE FIRST ELEMENT SHOULD
       SATISFY THE SEARCH, SINCE THEY ARE QUEUED IN ASSENDING ORDER
       WITH THE FIRST ELEMENT BEING THE ACTIVE ONE.
       THE QUEUE ELEMENT IS DEQUEUED AND RETURNED TO THE POOL.
       IF THERE IS ANOTHER CLOCK COMPARATOR QUEUE ELEMENT BEHIND
       IT, IT IS MADE THE ACTIVE ELEMENT AND THE CLOCK COMPARATOR
       IS SET FOR ITS VALUE; IF THERE ARE NO MORE CLOCK COMPARATOR
       REQUESTS BEHIND IT, THE CLOCK COMPARATOR IS SET FOR ALL
       HEX F'S. IN EITHER CASE, THEREAFTER THE USER TASK EXIT
       IS TAKEN

       AFTER THE EXIT HAS BEEN TAKEN, RETURN IS MADE TO
       THE DISPATCHER

Calls to Other Routines

       DMTDSP -   TO RESUME DISPATCHED PROCESSING