I wouldn't say I "must", but I will say I "might". :-) btw, did you know your posts and showing up twice? For me, anyway.
Frank >________________________________ > From: "McKown, John" <john.mck...@healthmarkets.com> >To: ASSEMBLER-LIST@LISTSERV.UGA.EDU >Sent: Tuesday, June 12, 2012 3:39 PM >Subject: Re: CEETERM and register 15 > >You can continue to use R15, if you really must. And it should work if you do >put the return code and modifer (both!) in the DSA area. > >John McKown > >Systems Engineer IV > >IT > > > >Administrative Services Group > > > >HealthMarkets® > > > >9151 Boulevard 26 . N. Richland Hills . TX 76010 > >(817) 255-3225 phone . > >john.mck...@healthmarkets.com . www.HealthMarkets.com > > > >Confidentiality Notice: This e-mail message may contain confidential or >proprietary information. If you are not the intended recipient, please contact >the sender by reply e-mail and destroy all copies of the original message. >HealthMarkets® is the brand name for products underwritten and issued by the >insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance >Company®, Mid-West National Life Insurance Company of TennesseeSM and The MEGA >Life and Health Insurance Company.SM > > > >> -----Original Message----- >> From: IBM Mainframe Assembler List >> [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU] On Behalf Of Frank Swarbrick >> Sent: Tuesday, June 12, 2012 4:20 PM >> To: ASSEMBLER-LIST@LISTSERV.UGA.EDU >> Subject: Re: CEETERM and register 15 >> >> So it sounds like the original author should have never used >> R15 in the first place for the base register. OK. >> >> The program doesn't use any macros other than the CEE ones I >> just added and ABEND. But I'll see if I can find a free >> register other than 14 (or 15 or 0 or 1!). It's pretty much >> used every other register at some point in the program, but >> hopefully I can get around that. >> >> I've been reading about "baseless" programming and all new >> code I've added uses it, but at this point it don't want to >> make too many changes to it. So is your suggestion to use >> RC=RETCODE,MODIFIER=MOD and have those two as part of my >> automatic storage area? Actually, if I do that I can >> probably get away (for now) with leaving it using R15, since >> those fields will be based on R13. >> >> I will try this out. Thanks for your help!!!! >> Frank >> >> >> >> >> >________________________________ >> > From: "McKown, John" <john.mck...@healthmarkets.com> >> >To: ASSEMBLER-LIST@LISTSERV.UGA.EDU >> >Sent: Tuesday, June 12, 2012 2:53 PM >> >Subject: Re: CEETERM and register 15 >> > >> >The reason for the L in CEETERM is because you can do >> CEETERM RC=VARNAME,MODIFIER=MODNAME where VARNAME and MODNAME >> are fullword areas. >> > >> >In general, in z/OS, you should __never__ use R0 (impossible >> actually), R1, R14, or R15 for a CSECT/RSECT base register. >> Many (most) IBM macros use these registers. And occassionally >> other registers as well. >> > >> >For LE enabled assembler (I have written some), when I use a >> base register at all (not often any more), I use R11 for my >> first, then R10, R9, and so as as the module grows in size. >> In "modern" programming, you can avoid the use of a "base >> register" for code in almost every case by using relative >> instructions instead of based instructions. E.g. use LARL >> instead of LA for areas in the CSECT, and Jxx instead of Bxx >> for branching. If you load constant values, try to use LHI if >> possible. Do try to write reentrant code. If you do that, you >> can keep the modifiable values in the DSA, which is addressed >> by R13 and which is set up for you with the CEEENTRY and >> CEEDSA macros. For a constant which does not fit into a >> halfword, or maybe is packed decimal or characters, you can >> replace somethin like: L R7,FULLWORD with 2 instructions: >> LARL R7,FULLWORD followed by L R7,0(,R7), and the same with >> packed and characters. OK, that is a bit ugly, I admit. >> > >> > >> >-- >> >John McKown >> >Systems Engineer IV >> >IT >> > >> >Administrative Services Group >> > >> >HealthMarkets® >> > >> >9151 Boulevard 26 . N. Richland Hills . TX 76010 >> >(817) 255-3225 phone . >> >john.mck...@healthmarkets.com . www.HealthMarkets.com >> > >> >Confidentiality Notice: This e-mail message may contain >> confidential or proprietary information. If you are not the >> intended recipient, please contact the sender by reply e-mail >> and destroy all copies of the original message. >> HealthMarkets® is the brand name for products underwritten >> and issued by the insurance subsidiaries of HealthMarkets, >> Inc. -The Chesapeake Life Insurance Company®, Mid-West >> National Life Insurance Company of TennesseeSM and The MEGA >> Life and Health Insurance Company.SM >> > >> >> -----Original Message----- >> >> From: IBM Mainframe Assembler List >> >> [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU] On Behalf Of >> Frank Swarbrick >> >> Sent: Tuesday, June 12, 2012 3:25 PM >> >> To: ASSEMBLER-LIST@LISTSERV.UGA.EDU >> >> Subject: CEETERM and register 15 >> >> >> >> First off please realize that I'm an assembler beginner. >> >> I've fiddled with it here and there for 15 years, but I'm >> >> really just a COBOL programmer. So please be gentle! :-) >> >> >> >> We have a vendor written, code supplied, subroutine that does >> >> for us a few things that COBOL can't (bit fiddling; posting >> >> of an ECB; etc.). This same exact routine is called both by >> >> batch COBOL program and CICS COBOL programs. It is not >> >> reentrant. In order to make it reentrant I have been working >> >> on "LE-enabling" it. This seems to work quite well! But I >> >> ran in to something "weird" with CEETERM. CEETERM RC=0 >> >> generates the following: >> >> >> >> 58F0 F098 013A0 1827+ L 15,=A(0) >> >> >> >> 5800 F098 013A0 1828+ L 0,=A(0) >> >> 58DD 0004 00004 1829+ L 13,4(13) >> >> 58E0 D00C 0000C 1830+ L 14,12(,13) >> >> 981C D018 00018 1831+ LM 1,12,24(13) >> >> 07FE 1832+ BR 14 >> >> >> >> Problem? The program uses register 15 as the base register. >> >> Funny thing is that the code actually "works". But it really >> >> doesn't. The first L sets R15 to 0. Then the second L loads >> >> in to R0 from 152(,R15), but of course R15 is now 0, not the >> >> real base address it needs to be. It's only coincidence that >> >> 152 bytes in to low core contains x'00000000'. If I tried to >> >> use an RC of some other value it would still be set to 0. >> >> >> >> >> >> I changed the program to use 14 instead of 15 for the base >> >> register and all is now fine. But I don't see it documented >> >> that CEETERM should not be used when the base is R15. Or is >> >> it just common practice to not use R15 as the base? Other >> >> than this one program I don't see that R15 is generally used >> >> for that purpose even though it starts out with the correct >> >> address, which is probably why it was used in this case. >> >> Specifically, the original code was this: >> >> SUBR CSECT >> >> >> >> USING *,RF >> >> B START >> >> DC CL8'SUBR' >> >> START DS 0H >> >> SAVE (14,12) >> >> >> >> Anyway, I have to wonder why CEETERM doesn't take a page from >> >> the RETURN macro, and use LA from an offset into "R0", i.e., >> >> if I had CEETERM RC=12,MODIFIER=8, we'd get something like this: >> >> >> >> LA 15,12(0) >> >> LA 0,8(0) >> >> L 13,4(13) >> >> L 14,12(,13) >> >> LM 1,12,24(13) >> >> BR 14 >> >> >> >> No base register needed, correct? (This is one of those >> >> cases where "register 0" is really just "zero", right, no >> >> matter what value it actually holds?) >> >> >> >> >> >> (Apologies to Russ Evans, if he is reading this, for taking >> >> an unexpected side trip to LE land.) >> >> >> >> Hope I've not shown too much ignorance. >> >> >> >> >> >> Thanks! >> >> Frank >> >> >> >> >> >> >> > >> > >> > >> >> > > >
