Type ASSEMBLE
Source Lines : 855
Fixes Applied : 7
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [R14923DS]

Module

       DMSSQS (SOQSAM - QUEUED SEQUENTIAL ACCESS METHOD)

Function

       TO  ANALYZE RECORD  FORMAT  AND  SET UP  THE  BUFFERS
       ACCORDINGLY FOR GET, PUT AND PUTX REQUESTS.

Attributes

       REENTRANT, NUCLEUS RESIDENT

Operation

       INITIALIZATION

          OSIOTYPE AND  IOBECBPT ARE SET TO  INDICATE ACCESS
          METHOD  AND  FCB  ADDRESS  RESPECTIVELY.   THEN, IF
          THE DUMMY OPTION IS NOT SPECIFIED IN THE FCB, A
          BRANCH  IS  TAKEN  TO  GETTER,  PUTTER  OR  PUTXER
          DEPENDING ON WHETHER THE REQUEST  IS A GET, PUT OR
          PUTX RESPECTIVELY.  IF DUMMY IS SPECIFIED IN THE FCB,
          CONTROL IS PASSED TO QSAMDUMY.

       GETTER

          AFTER  FCBIOSW AND  IOBIOFLG ARE  SET TO  INDICATE
          INPUT IN PROCESS, DCB  FIELDS DCBMACF AND DCBRECFM
          ARE ANALYZED TO DETERMINE THE TYPE OF MODE DESIRED
          - MOVE OR LOCATE - AND  THE RECORD FORMAT.  IF THE
          MODE IS MOVE, THE USER SPECIFIED 'MOVE TO' ADDRESS
          IS  STORED IN  DEBTCBAD.  BOTH  MODES CONTINUE  BY
          DETERMINING  WHETHER  IT  IS   CALLED  FROM  CLOSE
          (DMSSOP).  IF SO,  A CHECK  IS  MADE TO  DETERMINE
          WHETHER THE UPDATE FLAG (IOBUBD) IN THE "IOBIOFLG"
          IS  ON INDICATING  A  "PUTX"  ISSUED ON  THE  LAST
          BLOCK.

          IF THE UPDATE FLAG IS  NOT ON, CONTROL IS RETURNED
          TO CLOSE.

          IF THE UPDATE FLAG IS ON, CONTROL IS PASSED TO THE
          ROUTINE "GETXER" TO REWRITE  THE LAST BLOCK BEFORE
          RETURNING TO CLOSE. (SEE "GETXER" BELOW).

          IF  NOT  CALLED  BY  CLOSE, A  CHECK  IS  MADE  TO
          DETERMINE  WHETHER  AN "END  OF  BLOCK"  CONDITION
          EXISTS.

          IF "END OF  BLOCK" CONDITION DOES EXIST,   A CHECK
          IS MADE OF THE UPDATE  FLAG TO DETERMINE WHETHER A
          RECORD IN  THE JUST  COMPLETED BLOCK  WAS UPDATED.
          IF SO,  "GETXER" RECEIVES  CONTROL TO  REWRITE THE
          LAST BLOCK; (SEE "GETXER" BELOW). ROUTINE "SETEOB"
          THEN RECEIVES CONTROL TO GET  THE NEXT BUFFER FROM
          THE POOL; (SEE "SETEOB" BELOW).

          UPON RETURN  FROM "SETEOB",  THE APPROPRIATE  "FCB"
          FIELDS ARE UPDATED AND A CALL IS MADE TO DMSSEB TO
          FILL THE NEW BUFFER WITH THE NEXT BLOCK.

          UPON RETURN, THE  "FCBITEM" COUNT  IS UPDATED, AND
          THE "ECB" IS CHECKED FOR AN ERROR.  IF ONE EXISTS,
          CONTROL IS PASSED TO DMSSCT (CHECK SIMULATION).

          AFTER IT IS DETERMINED THAT THERE IS A RECORD IN THE
          BUFFER, THE RECORD IS DEBLOCKED FROM THE BUFFER AND, IF
          THE RECFM IS VARIABLE OR UNDEFINED, DCBLRECL IS SET TO THE
          LENGTH OF THE RECORD.  IF THE MODE IS LOCATE, CONTROL
          IS RETURNED TO THE USER WITH THE ADDRESS OF THE RECORD. IF
          THE MODE IS MOVE, THE RECORD IS MOVED TO THE ADDRESS
          PROVIDED BY THE USER AND CONTROL IS RETURNED TO THE USER.

       PUTTER

          RECEIVES  CONTROL  FROM "PUT"  MACRO  INSTRUCTION.
          AFTER "FCBIOSW" AND "IOBIOFLG" ARE SET TO INDICATE
          OUTPUT IN PROGRESS,  A CHECK IS MADE  TO DETERMINE
          WHETHER THIS CALL WAS MADE FROM CLOSE.

          IF NOT CALLED  FROM CLOSE AND THE  MODE IS LOCATE,
          AND THIS IS  THE FIRST "PUT" CALL,  THE ADDRESS OF
          THE  FIRST BUFFER  IS  PLACED  IN REGISTER  1  AND
          CONTROL IS RETURNED TO THE USER.

          IF CALLED FROM CLOSE, A CHECK IS MADE TO SEE IF A PUT
          IS NECESSARY. IF NOT, CONTROL IS RETURNED TO THE USER.
          IF A PUT IS NECESSARY, THE POINTERS ARE SETUP TO WRITE
          A SHORT BLOCK.

          IF  OTHER  THAN  THE  FIRST   "PUT"  CALL,  IT  IS
          DETERMINED   WHETHER   THE  CURRENT   BUFFER   HAS
          SUFFICIENT SPACE  FOR ANOTHER  RECORD.  IF  IT HAS,
          REGISTER 1 IS UPDATED  TO THE  ADDRESS  OF THE  NEXT
          RECORD WITHIN  THE CURRENT  BUFFER AND  CONTROL IS
          RETURNED TO THE CALLER.  IF  THE CURRENT BUFFER IS
          FULL,  A  CALL IS  MADE  TO  DMSSEB TO  WRITE  THE
          CURRENT BUFFER TO THE FILE.

          UPON RETURN FROM  DMSSEB THE "ECB" IS  CHECKED FOR
          ERROR  INDICATION AND  IF  ONE  EXISTS CONTROL  IS
          PASSED TO  DMSSCT (CHECK SIMULATION). IF  NO ERROR
          CONDITION EXISTS THE "FCBITEM" COUNT IS UPDATED TO
          REFLECT THE LAST BLOCK WRITTEN.

          ROUTINE "SETEOB" THEN RECEIVES  CONTROL TO GET THE
          NEXT BUFFER FROM THE  POOL;  (SEE "SETEOB" BELOW).
          IF LOCATE IS SPECIFIED, CONTROL IS RETURNED TO THE
          USER. IF MOVE MODE IS SPECIFIED, THE ROUTINE MOVEMODE
          IS USED TO MOVE THE RECORD INTO THE BUFFER AND CONTROL
          IS RETURNED TO THE USER.


       PUTXER

          RECEIVES  CONTROL FROM  "PUTX" MACRO  INSTRUCTION.
          SETS THE  UPDATE FLAG ("IOBUPD") IN  THE "IOBIOFLG"
          FIELD  OF THE  IOB TO  INDICATE  THAT THE  CURRENT
          BLOCK  HAS  BEEN  UPDATED AND  THEREFORE  WILL  BE
          REWRITTEN AT "END OF BLOCK" TIME. RETURNS
          CONTROL TO THE USER.

       GETXER

          RECEIVES CONTROL FROM ROUTINE  "GETTER" AT "CLOSE"
          TIME OR "END  OF BLOCK" TIME WHEN  THE UPDATE FLAG
          (IOBUPD)  HAS BEEN  SET  IN  THE "IOBIOFLG"  BY  A
          PREVIOUS "PUTX" CALL.

          THE "FCBIOSW"  AND "IOBIOFLG"  ARE CHANGED  FROM A
          "GET" CALL TO  A "PUT" CALL.  THE  "FCBITEM" COUNT
          IS RESET TO THE FIRST RECORD OF THE CURRENT BLOCK.

          DMSSEB IS CALLED TO REWRITE THE UPDATED BLOCK.

          UPON RETURN,  THE "ECB"  IS CHECKED  FOR AN  ERROR
          CONDITION.   IF ONE  EXISTS,  A  CALL IS  MADE  TO
          DMSSCT (CHECK SIMULATION). IF  NO ERROR INDICATION,
          THE "FCBITEM" COUNT IS RESTORED TO THE NEXT BLOCK,
          THE "FCBIOSW" AND "IOBIOFLG" ARE RESET TO INDICATE
          THE "GET" CALL AND IF NOT "CLOSE" TIME, CONTROL IS
          RETURNED  TO ROUTINE  "GETTER".   IF "CLOSE"  TIME
          CONTROL IS RETURNED TO DMSSOP (CLOSE).

       SETEOB

          RECEIVES   CONTROL  FROM   ROUTINES  "GETTER"   OR
          "PUTTER" AT "END OF BLOCK" TIME.

          DCB AND IOB ADDRESSES ARE  UPDATED TO POINT TO THE
          NEXT BUFFER  IN THE POOL AND CONTROL IS  RETURNED TO
          THE CALLING ROUTINE.

       MOVEMODE

          MOVES THE  RECORD  FROM THE
          USER BUFFER  TO THE SYSTEM  BUFFER IN THE  CASE OF
          "PUT"  AND FROM  THE  SYSTEM  BUFFER TO  THE  USER
          BUFFER  IN THE  CASE  OF  "GET". IT  THEN  RETURNS
          CONTROL TO THE CALLING ROUTINE.

       QSAMDUMY

          QSAMDUMY FIRST CHECKS TO DETERMINE IF A GET OR
          A PUT WAS ISSUED. IF A GET WAS ISSUED, AN END OF FILE
          ERROR CODE IS SET AND CONTROL IS PASSED TO DMSSCTCE.
          IF A PUT WAS ISSUED, CONTROL IS RETURNED TO THE USER
          WITH THE ADDRESS OF THE NEXT RECORD AREA IN REGISTER
          ONE.

Calls to Other Routines

       DMSSEB, DMSSCT