AM64 is very different than what you are have been asking for in this thread.
z/OS currently supports 3 addressing modes; AM24, AM31 and AM64. What you are asking for is a major re-architecting of z/OS to create AM32. As (IIRC) Peter Relson pointed out that JAVA is able to use this storage. As Jim Mulder pointed out, this is also a subset of AM64. I do not believe specific request is very likely to happen. My $USD 0.02 worth. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Paul Edwards Sent: Monday, May 7, 2018 7:44 AM To: [email protected] Subject: Re: GETMAIN LOC=32 On Mon, 7 May 2018 07:15:23 -0500, Tom Marchant <[email protected]> wrote: >>For an existing 32-bit program, being able to change LOC=31 or LOC=ANY >>to LOC=32 is the simplest change, and on an old system it will still >>work, just obtaining LOC=31 memory instead of LOC=32 memory, better >>than nothing. > >You want to change an AMODE(31) program to AMODE(64) and you think that >all you have to change is the GETMAIN? That's the best case scenario, yes. It depends on the application. As an example I recently asked the author of REVIEW what would be required to make his AM31/RM24 program work as AM64/RM24 and he didn't list much. REVIEW is a large assembler application that has been written over decades. Also, the things that need to change would also need to change if it was converted to a 64-bit application. It's a much less onerous task to keep it as a 32-bit application. >You haven't given it nearly enough thought Maybe we can list the situations: If any 31-bit addresses exist with a flag in the top bit, it can't be cleared with LA. You will need to do an N with X'7FFFFFFF' to clear it before it can be used at all. On program entry, R15 will not contain the entry point so you need to do a BALR R15,R0. You can't use a negative index and expect wrapping at 32 bits. GETMAIN R needs to change to GETMAIN RU,LOC=24 These are fairly minor things. Did I miss something? Oh - I'm also assuming that IBM will update the operating system so that READ etc can be executed in AM64. Just like they updated READ from AM24-only to bimodal in late MVS/ESA. But from the application side, there's not much, and we can start making those application changes now in anticipation of being able to run as AM64 in the future. BFN. Paul. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ::DISCLAIMER:: -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
