I have seen where the high half of R15 is not zero after a getmain with the low half (the return code) zero (this was several years ago and I have not checked to see if it still happens).
The following code (using lr) has potential issues Getmain ... Lr 15,1 St 3,0(,15) <- may not work very well in amode 64 if the high half is not zero anymore La 8,10(,15) <- it just got much worse Versus Getmain ... La 15,0(,1) St 3,0(,15) <- will work find in amode 64 The point is that the high halves of the registers (0,1,15) may not always be zero so code that is fine for am24/31 may not be fine for am64. ...chris. -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Paul Edwards Sent: May-09-18 4:46 PM To: [email protected] Subject: Re: GETMAIN LOC=32 On Wed, 9 May 2018 18:40:40 -0500, Paul Gilmartin <[email protected]> wrote: >>>"implausible"; various instructions work differently in AM24 and AM31, much >>>less AM64. >> >>It's not implausible, it's what I do. I produce 32-bit load modules >>that work on all 3 AMODEs. They passively accept whatever AMODE they >>were called with. They don't even require different code paths >>internally. >> >What about exploiting dual address space mode, AR mode, ESA, >Hiperspaces, any other historic side roads that mainframe development has >followed? > >I agree with Shmuel here, perhaps to his dismay. No, of course I can't use such features and have it still run all the way back to MVS 3.8j. But for basic applications, like diff3 or sed, that just do normal I/O, it can run in any AMODE. Basically if you stick to the capabilities that MVS 3.8j had, then you can write a program that will run in any AMODE, including AM64. BFN. Paul. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
