The documentation for SVC 120 does not apply to branch entries and does not describe the affected control blocks.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Paul Edwards <[email protected]> Sent: Wednesday, August 27, 2025 10:44 AM To: [email protected] <[email protected]> Subject: Re: GETMAIN LOC=RES reinterpretation External Message: Use Caution On Wed, 27 Aug 2025 17:25:57 +0300, Binyamin Dissen <[email protected]> wrote: >:>>:>>If your program, wherever it resides in storage, wishes >:>>:>> to get storage above 2G, it is fully capable of doing so >:>>:>> via IARV64 (or IARST64 or IARCP64). > >:>>:>That mechanism is undocumented, so I cannot and will >:>>:>not use that. > >:>>Huh?????? > >:>>MVS Programming: Assembler Services Reference, Volume 2 (IAR-XCT) > >:>Which control blocks are accessed when you code IARV64? What goes into the >user's executable? > >:>GETMAIN is fully documented. > >What part of the documentation are you finding difficult? > >IARV64 is fully documented: > >Chapter 6. IARV64 � 64�bit virtual storage allocation https://www.ibm.com/docs/en/zos/3.1.0?topic=allocation-requestgetstor-option-iarv64 Nothing there says what code the proprietary, copyrighted IARV64 macro GENERATES and thus appears in the binary executable. And I have no way of getting such information without looking at the code that it generates on a z/OS system. And if I do that, I may be accused of reverse-engineering, and all my work is invalidated. The code that GETMAIN generates can be ascertained by looking at the documentation for SVC 120. Every bit of every register is documented, so I can write a compatible system (I have more than one already, and plan to add another two - one that runs under z/Linux and one that is an extension to z/PDOS-generic). If it were up to me, I'd use that anti-trust legislation to require IBM to: 1. Document the OS interface that IARV64 depends on. 2. Add LOC=64 or similar to GETMAIN - if they want to get SVC 120 to call IARV64 - go for it - that's internal - I don't care. But since it's not "up to me", I'm instead trying to finess a workaround. 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
