Type ASSEMBLE
Source Lines : 513
Fixes Applied : 6
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [R15172DS]
Module
DMSSBS (DMSSBS - BASIC SEQUENTIAL ACCESS METHOD)
Function
THE CMS BSAM ROUTINE PROCESSES SEQUENTIAL READ AND
WRITE MACROES.
Attributes
REENTRANT, NUCLEUS RESIDENT
Operation
THE CMS BSAM ROUTINE IS CALLED BY AN OS READ OR WRITE
MACRO. IT CHECKS DCBFDAD TO SEE IF THE FIRST BYTE IS
A P. IF SO, THE CONTENTS OF THE LAST TWO BYTES OF
DCBFDAD ARE INCREMENTED BY ONE AND STORED IN FCBITEM.
IF P IS SPECIFIED AND THE DEVICE IS A TAPE, DMSTIO
IS USED TO BACKSPACE OR FORWARD SPACE TO THE SPECIFIED
ITEM. NEXT THE FCB DUMMY OPTION IS CHECKED. IF IT
IS SPECIFIED, HEX '4200000C' (EOF ERROR) OR HEX '7F000000'
(NO ERROR) IS STORED IN THE ECB, DEPENDING ON WHETHER A
READ OR WRITE WAS ISSUED, AND CONTROL IS RETURNED TO THE
USER. IF THE FCB DUMMY OPTION IS NOT SPECIFIED, THE
DSORG OPTION IS CHECKED.
. IF THE DSORG OPTION IN THE DCB IS DA (DIRECT
ACCESS), CONTROL IS GIVEN TO THE
DMSSBD ROUTINE TO
CONVERT THE RECORD IDENTIFICATION INTO AN ITEM NUMBER
AND PROCESS
ANY KEYS USED. IF DMSSBD COMPLETES SUCCESSFULLY,
CONTROL IS RETURNED TO DMSSBS.
OTHERWISE, CONTROL IS RETURNED TO THE USER WITH AN
ERROR CODE.
. IF THE DSORG OPTION IN THE DCB IS PO (PARTITIONED
ORGANIZATION) AND A WRITE IS SPECIFIED AND THE FCBPDS
ENTRY IS ZERO, CONTROL IS PASSED TO THE PDSSAVE
ROUTINE
IN DMSSVT
TO SAVE THE DIRECTORY OF THE PDS (PARTITIONED DATA
SET) AND POINT THE FCB FILE ITEM NUMBER TO A FREE
MEMBER SLOT. IF PDSSAVE COMPLETES SUCCESSFULLY,
CONTROL IS RETURNED TO DMSSBS. OTHERWISE, CONTROL IS
RETURNED TO THE USER WITH AN ERROR CODE.
. IF THE DSORG OPTION IN THE DCB IS PS (PHYSICAL
SEQUENTIAL) AND THE MACRF OPTION IS WL (CREATE A BDAM
DATA SET)*, AN EIGHT IS PUT IN REGISTER 15 AND A
CHECK IS MADE TO SEE IF END OF EXTENT HAS BEEN
REACHED. IF SO, CONTROL IS RETURNED TO THE USER. IF
NOT, REGISTER 15 IS SET TO ZERO AND A CHECK IS MADE
OF THE OPTION SPECIFIED IN THE WRITE MACRO'S DECB.
IF SZ IS SPECIFIED AND THE KEYLENGTH IS ZERO,
CONTROL IS RETURNED TO THE USER WITH A HEX '7F'
IN THE ECB. IF SD OR SZ IS SPECIFIED AND THE
KEYLENGTH IS NONZERO, DMSSBD IS CALLED TO WRITE
256 DUMMY KEYS AND
UPON RETURN FROM DMSSBD CONTROL IS PASSED BACK
TO THE USER WITH A HEX '7F' IN THE ECB. IF SD IS
IS SPECIFIED AND THE KEYLENGTH IS ZERO, A KEY OF X'FF' IS
PUT IN THE DATA AREA AND DMSSBS PROCESSES THE DATA AS A
NORMAL WRITE. IF SF IS
SPECIFIED, A HEX '7F' IS STORED IN THE ECB AND IF THE
KEYLENGTH IS NOT ZERO
DMSSBD IS CALLED TO PROCESS A KEY. IF THE DMSSBD
ROUTINE
AND/OR THE CHECK FOR VALID OPTIONS IS COMPLETED
SUCCESSFULLY DMSSBS BEGINS FILLING IN THE IOB AND THE
I/O PLIST. OTHERWISE CONTROL IS RETURNED TO THE
USER WITH A HEX '42' IN THE ECB, DENOTING AN ERROR.
. IF THE DSORG OPTION IN THE DCB IS PS OR PO AND A
NONZERO KEYLENGTH IS SPECIFIED AND THE MACRF OPTION IS
NOT WL, DMSSBD IS CALLED TO READ OR WRITE A KEY. IF
DMSSBD COMPLETES SUCCESSFULLY, DMSSBS BEGINS FILLING
IN THE I/O PLIST. IF NOT, CONTROL IS RETURNED TO
THE USER WITH A HEX '42' IN THE ECB.
. AFTER THE NECESSARY CHECKS AND CALLS FROM DMSSBD
AND PDSSAVE ARE MADE, DMSSBS FILLS IN THE IOBIOFLG
BIT, THE IOTYPE BYTE, THE DCBOFLGS BIT, THE BUFFER
LENGTH, THE BUFFER
ADDRESS, THE DECB I/O STARTED BIT, THE IOB POINTER IN
THE DECB AND THE ECB POINTER IN THE IOB.
CONTROL IS THEN PASSED TO THE DMSSEB ROUTINE TO DO
THE I/O AND FILL IN THE ECB.
AFTER CONTROL IS PASSED BACK TO DMSSBS FROM DMSSEB,
CONTROL IS PASSED BACK TO THE USER.
* IF THE WL (CREATE A BDAM DATA SET) OPTION IS
SPECIFIED, THE NUMBER OF RECORDS IN THE DATA SET
EXTENT MUST BE SPECIFIED USING THE FILEDEF
COMMAND. THE DEFAULT SIZE IS 50 RECORDS.
Calls to Other Routines
DMSSBD, DMSSVT, DMSSEB, DMSTIO