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