On Tue, 14 Sep 2010 14:22:46 -0400 George Henke <gahe...@gmail.com> wrote:
:>Which compromises the entire purpose of the SAVE/RESTORE Register Convention :>which has been held "sacred" since the beginning of S/360, PCP, and/or "S" :>cubed. In what way? R15-R1 are documented as volatile. If you want to save them across system calls, you need to so it yourself. If you want to save all 64 bits, you need to do it yourself. No pre-Z program is affected as the top halves did not exist, thus nothing is broken. :>On Tue, Sep 14, 2010 at 1:28 PM, Binyamin Dissen <bdis...@dissensoftware.com :>> wrote: :>> On Tue, 14 Sep 2010 11:08:59 -0500 Walt Farrell <wfarr...@us.ibm.com> :>> wrote: :>> :>On Tue, 14 Sep 2010 10:26:30 -0500, McKown, John :>> :><john.mck...@healthmarkets.com> wrote: :>> :>>> -----Original Message----- :>> :>>> From: IBM Mainframe Discussion List :>> :>>> [mailto:ibm-m...@bama.ua.edu] On Behalf Of Paul Gilmartin :>> :>>> Sent: Tuesday, September 14, 2010 10:23 AM :>> :>>> To: IBM-MAIN@bama.ua.edu :>> :>>> Subject: Re: z/OS V1.12 differences and z196 (the new :>> :>>> mainframe) impacts :>> :>>> On Tue, 14 Sep 2010 11:04:47 -0400, David Cole wrote: :>> :>>> >>Except for regs 0,1,15 your assertion is true. :>> :>>> >>The high halves of those regs are not preserved across any interface :>> :>>> >>unless otherwise documented. :>> :>>> >This is in contradiction to a verbal statement he made at a :>> :>>> >presentation several years earlier wherein he flatly stated that no :>> :>>> >preexisting AMODE(24/31) program would ever behave differently (due :>> :>>> >to the widening of the registers) when run in z/OS vis-a-vis OS/390. :>> :>>> >Unfortunately, I don't have "the video". :>> :>>> Ah, semantics! Can a program run in AMODE(24/31) in OS/390 :>> :>>> (in a supported configuration) and use grande registers? :>> :>>Sure. Why not. I use them for 64 bit numbers where I used to use a :>> register :>> :>pair. Can OS/390 run on z hardware? I don't remember anymore. But use of :>> :>Grande registers in application code cannot be stopped by the OS. Of :>> course, :>> :>if you call other routines, you'd better store them yourself. Because :>> :>somebody else might be doing the same. :>> :>In this context, John, it seems to me that "pre-existing" means "before :>> :>64-bit registers existed", and thus your programs that use 64-bit :>> registers :>> :>don't count. Pre-existing programs would only use 32-bit registers, and :>> :>would not have any knowledge of the high-halves of the 64-bit registers, :>> and :>> :>are not affected by this change. :>> I have to agree with IBM in this context. Pre-Z programs did not use the :>> top :>> half and thus can run unchanged. New Z programs have to take into :>> consideration that the entire 64 bits of R15-R1 can change. -- Binyamin Dissen <bdis...@dissensoftware.com> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
