Type ASSEMBLE
Source Lines : 130
Fixes Applied : 0
Most Recent Version : Thursday, December 7, 1978
Last Fix ID : [Unmodified]

Module

       DMTVEC

Function

       THE DMTVEC  MODULE DESCRIBES  THE FIXED  ADDRESS
       STORAGE UTILIZATION  FOR MSUP,  BEGINNING AT  MAIN
       STORAGE ADDRESS X'200'. STORAGE UTILIZATION OF THE
       FIRST  512 BYTES  OF MAIN  STORAGE  IS DEFINED  BY
       S/370   ARCHITECTURE,   AND  IS   USED   BY   MSUP
       EXCLUSIVELY FOR THE PURPOSES SO DEFINED. THIS AREA
       IS  NOT   INCLUDED  IN  THE  DMTVEC   MODULE  TO
       FACILITATE INITIAL SYSTEM LOADING (THE CONTENTS OF
       THE  MACHINE  DEFINED  LOW   ADDRESS  STORAGE  ARE
       INITIALIZED BY DMTINI AT IPL TIME).

Attributes

       THERE IS NO EXECUTABLE CODE IN THIS MODULE

Operation

       STARTING AT MAIN STORAGE  ADDRESS X'200', DMTVEC
       DEFINES:
             1.  FIELDS  FOR  USE BY  THE  MSUP  EXECUTION
             CONTROL  SYSTEM, INCLUDING  A DISPATCHEE  NEW
             PSW  FIELD,  A  TWO  FULLWORD  SAVE  AREA,  A
             ONE-BYTE ID OF THE  LAST DISPATCHED TASK, AND
             A THREE-BYTE ADDRESS OF  THE TASK ELEMENT FOR
             THAT TASK;

             2.  A FULLWORD  ADDRESS OF  THE MAIN  STORAGE
             MAP, AND A  FULLWORD COUNT OF TOTAL  PAGES IN
             MAIN STORAGE (CONTIGUOUS,  STARTING WITH PAGE
             0);

             3.  TEN  FULLWORD  ADDRESSES  DESCRIBING  THE
             SUPERVISOR STATUS QUEUE CONFIGURATION;

             4. ELEVEN FULLWORD ADDRESSES  OF ENTRY POINTS
             FOR THE VARIOUS SUPERVISOR SERVICE ROUTINES;

             5. EIGHT FULLWORDS (INITIALIZED TO 0) FOR USE
             AT THE TASK PROGRAMMING LEVEL.