Build the parameter list once using this form:
CALL (15),(PARM1,PARM2,PARM2,BLOCK,PARM5),VL,MF=(E,PARMB), X
LINKINST=NOPR,LINKOP='0'
Which generates this code:
+ DS 0H
+ LA 1,PARMB LOAD PARAMETER REG 1
+ LA 0,PARM1 PICKUP PARAMETER
+ ST 0,0(0,1) STORE INTO PARAM. LIST
+ LA 0,PARM2 PICKUP PARAMETER
+ ST 0,4(0,1) STORE INTO PARAM. LIST
+ LA 0,PARM2 PICKUP PARAMETER
+ ST 0,8(0,1) STORE INTO PARAM. LIST
+ LA 0,BLOCK PICKUP PARAMETER
+ ST 0,12(0,1) STORE INTO PARAM. LIST
+ LA 0,PARM5 PICKUP PARAMETER
+ ST 0,16(0,1) STORE INTO PARAM. LIST
+ OI 16(1),X'80' SET LAST WORD BIT ON @G860P40
+ NOPR 0
The only extra cost is the “NOPR 0” at the end, but since you do it only once
that shouldn’t be an issue.
Then you can use your 3-instruction sequence to actually do the CALL as many
times as you need.
Peter
From: IBM Mainframe Assembler List <[email protected]> On Behalf
Of Dave Clark
Sent: Wednesday, October 18, 2023 12:48 PM
To: [email protected]
Subject: Re: Variable-Length Parameter List Attributes
"IBM Mainframe Assembler List"
<[email protected]<mailto:[email protected]>> wrote
on
10/18/2023 12:15:12 PM:
> Execute version of the CALL macro with MF=(E,parm_area_name) can fix
that.
Well, the other issue is performance. I potentially call this
program hundreds of times. So, I can build the parameter list just once
and call it as follows:
LA R1,SHVPARMB
L R15,ARXEXCOM
BALR R14,R15
Or I can call it as follows -- much less desireable. Note that
the program address is not supplied by a V-con but by an external program
vector list from REXX. That is why I have to preload R15 rather than
puting it in the CALL statement. But, I still wouldn't want a V-con
inserted into the middle of my instructions by the CALL with a branch
around it.
L R15,ARXEXCOM
CALL (15),(SHVPARM1,SHVPARM2,SHVPARM2,SHVBLOCK,SHVPARM5), X
MF=(E,SHVPARMB)
DS 0H
LA 1,SHVPARMB
LA 0,SHVPARM1
ST 0,0(0,1)
LA 0,SHVPARM2
ST 0,4(0,1)
LA 0,SHVPARM2
ST 0,8(0,1)
LA 0,SHVBLOCK
ST 0,12(0,1)
LA 0,SHVPARM5
ST 0,16(0,1)
OI 16(1),X'80
BALR 14,15
Sincerely,
Dave Clark
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