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
