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.