Type ASSEMBLE
Source Lines : 898
Fixes Applied : 1
Most Recent Version : Wednesday, December 13, 1978
Last Fix ID : [HRC013DK]

Module

       DMKTMR

Function

       TO SIMULATE THE CPU TIMER AND TIME OF DAY CLOCK COMPARATOR
       INSTRUCTIONS FOR VIRTUAL SYSTEM 370'S OPERATING IN EXTENDED
       CONTROL MODE

Attributes

       REENTRANT, RESIDENT, ENTERED VIA GOTO FROM DMKPRV

Operation

   SECTION A. - INITIALIZATION

       1. IF THE OPERATION IS SCK, SKIP TO STEP 3; OTHERWISE, CON-
          TINUE
       2. IF THE USER IS NOT IN EXTENDED PSW MODE, REFLECT AN OPER-
          ATION EXCEPTION
       3. GET THE ADDRESS SPECIFIED IN THE INSTRUCTION; IF IT IS NOT
          DOUBLE WORD ALIGNED, REFLECT A SPECIFICATION EXCEPTION
       4. TRANS FOR USER DATA PAGE; IF THE RESULTING CONDITION CODE
          INDICATES A VIRTUAL ADDRESSING ERROR, REFLECT IT
       5. IF THE INSTRUCTION IS NOT A STORE (2ND OPCODE BYTE IS NOT
          ODD), SKIP TO STEP 7; OTHERWISE, CONTINUE
       6. COMPARE THE VIRTUAL PSW KEY TO THE STORAGE KEY IN THE
          USER'S PAGE; IF THEY DO NOT AGREE AND IF THE PSW KEY
          IS NON-ZERO, REFLECT A PROTECTION EXCEPTION
       7. GET THE 2ND OPCODE BYTE AND BRANCH TO HANDLE THE REQUESTED
          INSTRUCTION AS DESCRIBED IN SECTIONS B THROUGH F BELOW

Calls to Other Routines

       DMKPTRAN - TO LOCATE THE USER'S DATA AREA IN HIS VIRTUAL
                  MEMORY
       DMKPSAFP - TO CHECK FOR FETCH PROTECTION
       DMKPSASP - TO CHECK FOR STORAGE PROTECTION
                  INSTRUCTIONS
       DMKSCHST - TO ESTABLISH A TOD COMPARATOR INTERRUPT REQUEST
       DMKSCHRT - TO RESET A TOD COMPARATOR INTERRUPT REQUEST
       DMKSTKIO - TO STACK A PENDING CLOCK COMPARATOR INTERRUPT
       DMKDSPCH - EXIT VIA GOTO IF INTERRUPT IS PENDING
       DMKPRGSM - EXIT VIA GOTO TO REFLECT A PROGRAM INTERRUPT
       DMKSTKDE - TO STACK A DEFERRED USER TASK
       DMKDSPRU - TO RUN USERS WITHOUT SYSTEM LOCK