Hello readers.
I've got an old problem state assembler program that does certain sub
totaling whenever the DCB EXLST 16 is driven. When exit 16 is driven,
the current dataset name is obtained from the JFCB and a totaling
subprogram is called. DCB EXLST 13 and 16 are used.
Exit 16 is documented as reserved. However my code labels it as some
type of EOV exit. When executing exit 16, my code does not use
information provided by registers 0 or 1. All registers are saved on
entry and restored prior to exit.
>From the doc and based on my understanding, the documented EOV exits
are driven on VOLUME switch or on DSN switch when like-DCB datasets
are concatenated.
The program is being converted to COBOL. The IO and RDJFCB will be
placed in an assembler subroutine.
My questions is, when is EXLST 16 driven? And if anyone knows, what
is the purpose of exit 16?
Thanks,
Sam
P.S. Relevant sections of code are listed below.
************* start RDJFCB code ********************
OPEN DS 0H
OPEN (INTRANS,(INPUT))
RDJFCB (INTRANS) GET INTRANS ALLOC RETRIEVAL LIST
MVC SVARLA,ARLAREA SAVE ADDR TO ALLOC RETRIEVAL LIST
MVC JFCB#,ARLRTRVD SAVE # JFCB'S RETRIEVED
L R14,SVARLA ADDRESS JFCB FOR DSN
MVC DSNNAME,4(R14) MOVE DSNNAME TO SUB208 PARM
************* end RDJFCB code ********************
*************** start of dcb exit 16 ************************
EXEOV DS 0H
STM R0,R15,SAVEEX
LA R13,SAVEEX2
MVC FUNCTION,=C'SUB' INDICATE SUBTOTAL
CALL GETSUB,(SUB208,PARMPR),VL
SR R2,R2 CLEAR REGISTER
LH R2,JFCB# LOAD NUMBER OF JFCB'S REMAINING
EXEOV1 BCTR R2,0 DECREMENT # OF JFCB'S REMAINING TO
SH R2,JFCB# ..LIST AND SAVE IT FOR LATER
L R14,SVARLA ADDRESS JFCB FOR DSN
SR R2,R2 CLEAR REGISTER
LH R2,0(R14) LOAD LENGTH OF JFCB ENTRY
AR R14,R2 POINT TO NEXT JFCB IN ALLOC LIST
MVC DSNNAME,4(R14) MOVE DSNNAME TO SUB208 PARM
ST R14,SVARLA SAVE ADDRESS JFCB
LM R0,R15,SAVEEX
*************** end of dcb exit 16 ************************
*************** start of DCB and EXLST definition ************************
INTRANS DCB DDNAME=INTRANS, *
MACRF=GM, *
DSORG=PS, *
EXLST=EXLST, *
EODAD=RDINEOF
EXLST DS 0F
DC X'13',AL3(EXJFCB)
DC X'86',AL3(EXEOV) ..FLAG END OF LIST
EXJFCB IHAARL DSECT=NO
*************** end of DCB and EXLST definition ************************
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