CORRECTION: R4 (was R5)
Below, an improvement (i) and a mandatory (m) change suggestion:
Date: Fri, 2 Oct 2015 13:57:34 -0400
From: Scott Ford <[email protected]>
Subject: Branch table
All:
I am building a branch table like this:
BTAB DSECT
BADD DS AL4 or Y(..) i Routine address
BFUN DS CL10 Function code
BNXT DS 0AL4 or EQU * i (Align to) Next item
BLEN EQU *-BADD One item length
PROG CSECT , (or LOCTR)
* ---------------------------------------------------
FUNC DS CL(L'BFUN) Input
FUNCTBL DS 0X i Table
DC AL4(INIT_DSP),CL(L'BFUN)'INIT'
DC AL4(KILL_DSP),CL(L'BFUN)'KILL'
DS 0X i Align end
TBLENT EQU (*-FUNCTBL)/BLEN
* ---------------------------------------------------
LA R4,FUNCTBL Start of table
USING BTAB,R4
LHI R5,TBLENT Item count
LOOPTBL DS 0H
CLC FUNC,BFUN This one?
JE FOUND_IT Yes - handle
LA R4,BNXT m incr scan ptr !!
JCT R5,LOOPTBL No - try next
J ENDOFDAYS Not found
FOUND_IT DS 0H
L R15,BADD Routine address
DROP R4
BASR R14,R15 Execute routine
* etc...
* ---------------------------------------------------
If you hae many table entries I'd use Y(..) instead of AL4(..)
Andreas Geissbuehler
