Type ASSEMBLE
Source Lines : 2,028
Fixes Applied : 3
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [R12931DS]
Module
DMSVIP - CMS VSAM INTERFACE PROCESSOR *
Function
DMSVIP PERFORMS THE FOLLOWING: *
1. LOADS THE DOS DCSS (VSAM OPTION SPECIFIED). *
2. ISSUES ALL NECESSARY DOS ASSGN COMMANDS FOR THE OS *
USER. *
*
3. MAPS ALL OS VSAM MACRO REQUESTS TO DOS SPECIFICATIONS *
(INCLUDING MODIFICATION OF VSAM CONTROL BLOCKS AND *
USER PARAMETER LISTS). *
*
4. PERFORMS SIMULATION FOR OS ASYNCHRONOUS VSAM DATA *
MANAGEMENT REQUESTS. *
*
5. MAPS DOS VSAM MACRO RETURN CODES AND ERROR CODES TO OS *
EQUIVALENTS WHERE NECESSARY. *
*
6. TRAPS ALL TRANSFERS OF CONTROL BETWEEN VSAM AND THE OS *
USER AND SETS THE APPROPRIATE OPERATING ENVIRONMENT FLAGS.*
*
*
Attributes
EXECUTES IN CMS VSAM DCSS, REENTRANT *
Operation
INITIALIZATION- *
UPON FIRST CALL TO THE INTERFACE, A 'SET DOS ON (VSAM '*
COMMAND IS ISSUED TO LOAD THE DOS SEGMENT. THEN, THE *
CHAIN OF DOSCB'S IS SEARCHED AND DOS ASSGN COMMANDS *
ARE ISSUED FOR THE OS USER. *
*
OPEN (SVC19)- *
*
ALL OS ACB'S ARE REARRANGED TO DOS FORMAT PRIOR TO *
OPEN. IN ADDITION, ANY EXIT LISTS POINTED TO BY THE *
ACB'S ARE REARRANGED IF NECESSARY. THE ADDRESSES OF *
EXIT ROUTINES CONTAINED THEREIN ARE REPLACED BY THE *
ADDRESS OF DMSVIP3 TO ALLOW VIP TO GAIN CONTROL *
PRIOR TO THE USER EXIT (SEE BELOW). *
*
A DOS OPEN IS THEN ISSUED VIA DOS SVC 2 TO $$BOPEN. *
ANY DOS ERROR CODES THAT DO NOT EXIST IN OS ARE *
MAPPED TO OS EQUIVALENTS. THE A(DMSVIP2) (ACTION MACRO *
ENTRY POINT) IS STORED IN ALL SUCCESSFULLY OPENED *
ACB'S, AND CONTROL IS RETURNED TO THE CALLER (DMSSOP). *
*
CLOSE (SVC20), TCLOSE(SVC23)- *
*
THESE REQUESTS ARE MADE VIA DOS SVC 2 TO $$BCLOSE. *
FOR TCLOSE, A FLAG IS SET IN THE NUCLEUS TO DIRECT *
$$BCLOSE TO CALL $$BTCLOS AFTER PROCESSING THE SVC *
PLIST. *
*
THE A(IKQVSM) (VSAM DATA MGT REQUEST DRIVER) IS STORED *
IN ALL ACB'S PRIOR TO THE SUPERVISOR CALL. ON RETURN, *
THE A(DMSVIP2) IS RESTORED IN THE ACB UNCONDITIONALLY *
FOR TCLOSE REQUESTS, AND IN UNSUCCESSFULLY CLOSED ACB'S*
FOR CLOSE REQUESTS. CONTROL IS RETURNED TO THE CALLER. *
*
NOTE THAT FOR OPEN, CLOSE AND TCLOSE REQUESTS, AN ACB *
LIST IS BUILT IN FREE STORAGE FROM THE USER'S PLIST *
AND PASSED TO DOS. THE LIST IS DMSFRET'D UPON RETURN *
FROM VSAM. *
*
*
GET, PUT, POINT, ENDREQ, ERASE- *
*
THE REQUEST CODE IN REGISTER ZERO IS MAPPED TO THE *
EQUIVALENT DOS REQUEST CODE. NEXT, THE RPL (OR CHAIN *
OF RPL'S) IS REARRANGED TO DOS FORMAT IF NOT PREVIOUSLY*
DONE. IF THE USER HAS PROVIDED AN ECB ADDRESS IN THE *
OS RPL, A FLAG IS SET IN THE NEW DOS RPL AND THE ECB *
ADDRESS IS SAVED AT THE END OF THE BLOCK. ASYNCHRONOUS *
PROCESSING IS SIMULATED BY THE SETTING OF ANY ACTIVE *
EXIT RTNS INACTIVE WITHIN THE USER EXLST (WITH THE *
EXCEPTION OF A JRNAD EXIT WHICH IS NOT AN ERROR EXIT). *
THIS PREVENTS VSAM FROM TAKING AN ERROR EXIT AND ALLOWS*
SUCH AN EXIT TO BE DEFERRED UNTIL A CHECK IS ISSUED *
(SEE BELOW). *
*
THE DOS MACRO IS THEN ISSUED VIA A BALR TO IKQVSM. *
*
ALL DOS ERROR CODES IN THE RPL FDBK FIELD THAT DO NOT *
EXIST IN OS ARE MAPPED TO OS EQUIVALENTS. *
IF THE USER HAS SPECIFIED SYNCHRONOUS PROCESSING, THE *
RETURN CODE IS PASSED UNCHANGED IN REGISTER 15. *
*
FOR ASYNCHRONOUS PROCESSING, ANY RETURN CODE IS *
CLEARED BEFORE RETURN AND PREVIOUSLY SET INACTIVE *
EXIT ROUTINES ARE RESTORED TO ACTIVE STATUS IN THE *
EXLST. (SEE DESCRIPTION OF CHECK MACRO, BELOW, FOR *
FURTHER COMMENTS). ALL ECB'S ARE SET TO 'WAITING' *
STATUS. *
*
CHECK- *
*
THE RPL FDBK FIELD IS EXAMINED FOR THE RESULTS OF THE *
PREVIOUS I/O OPERATION ON THE VSAM DATA SET. CONTROL *
IS PASSED TO THE APPROPRIATE EXIT ROUTINE, IF AN *
ACTIVE ONE HAS BEEN PROVIDED. ALSO, ALL 'WAITING' *
ECB'S ARE POSTED WITH AN EQUIVALENT COMPLETION CODE. *
*
IF NO ACTIVE EXIT ROUTINE EXISTS, OR IF AN EXIT ROUTINE*
'RETURNS TO VSAM', THE RETURN CODE IS SET IN REGISTER *
15, AND CONTROL IS RETURNED TO THE USER INSTRUCTION *
FOLLOWING THE CHECK. *
*
GENCB- *
*
FOR GENCB BLK=ACB OR BLK=EXLST, A DOS GENCB REQUEST *
IS ISSUED VIA BALR TO IKQGEN. THE PLIST IS UNCHANGED. *
*
IF THE GENCB IS FOR AN RPL, AND THE USER HAS SPECIFIED *
THE ECB KEYWORD, THE PLIST IS REARRANGED TO EXCLUDE *
THE ECB ELEMENT, SINCE IT IS NOT SUPPORTED IN DOS. *
A DOS GENCB IS THEN ISSUED AND, IF THE USER HAS *
PROVIDED A WORKAREA, THE ADDRESS OF THE ECB IS STORED *
AT THE END OF THE RPL AND A FLAG IS SET IN THE RPL. *
THE PLIST IS RESTORED BEFORE CONTROL IS RETURNED TO *
THE USER. *
*
MODCB, SHOWCB, TESTCB- *
*
IF A MODCB IS ISSUED FOR AN OS ACB, RPL OR EXLST, *
THE CONTROL BLOCK IS REARRANGED TO DOS FORMAT BEFORE *
A BALR TO IKQTMS. THE ECB KEYWORD IS NOT ALLOWED ON *
A MODCB, SHOWCB OR TESTCB. *
*
IF THE REQUEST IS FOR TESTCB IO=COMPLETE, A 'NOT EQUAL'*
OR 'WAITING' RESULT IS UNCONDITIONALLY RETURNED TO THE *
USER. ALL OTHER SUPPORTED TESTCB REQUESTS ARE PASSED *
TO DOS, AND THE USER CAN RELY ON THE PSW CONDITION CODE*
TO INDICATE THE RESULTS OF THE TEST. *
*
IF AN ERET EXIT IS PROVIDED FOR TESTCB, THE A(DMSVIP4) *
IS SUBSTITUTED IN THE PLIST TO ALLOW VIP TO GAIN CONTROL
PRIOR TO ERET ENTRY AND SET THE PROPER SVC BIT (DOS BIT*
OFF). THE ERET ADDRESS IS RESTORED TO THE PLIST PRIOR TO
RETURN TO THE USER FOLLOWING THE TESTCB. *
*
VSAM EXIT TO USER EXIT RTN- *
*
ENTRY TO THE INTERFACE IS MADE AT DMSVIP3 FOR ALL *
VSAM ERROR EXITS DURING I/O. THE DOS SVC BIT IS TURNED *
OFF AND USER STORAGE KEY IS RESTORED. *
*
THE ADDRESS OF THE USER ROUTINE IS RECOVERED FROM *
THE SAVED LIST (EITHER THE PRIMARY LIST IN THE WORK AREA
OR FROM AN OVERFLOW LIST- OEXLSA). *
*
CONTROL IS THEN PASSED DIRECTLY TO THE EXIT ROUTINE. *
IF THE ROUTINE 'RETURNS TO VSAM', VIP3 RESETS THE *
ENVIRONMENT FLAGS, AND BRANCHES BACK TO VSAM. *
*
NOTE THAT THE INTERFACE IS CAPABLE OF SAVING UP TO *
128 DISTINCT EXIT ROUTINE ADDRESSES DURING A RUN UNIT. *
*
VSAM EXIT TO USER ERET RTN- *
*
ENTRY TO THE INTERFACE IS MADE AT DMSVIP4 FOR ALL *
VSAM EXITS TO A USER ERET ROUTINE DURING TESTCB MACRO *
REQUESTS. THE DOS SVC BIT IS TURNED OFF AND USER *
STORAGE KEY RESTORED. *
*
THE ADDRESS OF THE ERET ROUTINE IS RECOVERED FROM THE *
WORK AREA AND CONTROL IS PASSED TO THE ROUTINE. *
*
NOTE THAT THE ERET ROUTINE IS RESTRICTED FROM RETURNING*
CONTROL TO VSAM. *
*
NOTE - PROGRAMMER CODE = @V305174 *
*
Calls to Other Routines
IKQGEN, IKQVSM, IKQTMS, $$BOPEN, $$BCLOSE *