True, but there are lot's of reasons for not wanting to port your 31-bit C/C++ to 64 bit.
One example is when you are using XPLINK-31 with C/C++ and have a bunch of XPLINK assembler that calls system services/macros that require 31-bit parameters. Being able to use pointers to C/C++ data directly or even use the XPLINK-31 stack is very nice. Porting would be non-trivial, and could negatively affect performance. I wonder: are IBM z/OS products written in C, like Shells and Utilities, OpenSSH, etc 31 bit or 64 bit? Kirk Wolf Dovetailed Technologies https://coztoolkit.com On Fri, Nov 1, 2024, at 12:24 PM, Seymour J Metz wrote: > What are you trying to ask? How wide are your data? > > In general, if you run AMODE64 then you need to ensure that all 64 bits of > your base and index registers are valid. > > -- > Shmuel (Seymour J.) Metz > http://mason.gmu.edu/~smetz3 > עַם יִשְׂרָאֵל חַי > נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר > > > > ________________________________________ > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of > Mike Schwab <000005962a42dc49-dmarc-requ...@listserv.ua.edu> > Sent: Friday, November 1, 2024 1:15 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: 32 bit > > Caution: This email did not originate from George Mason’s mail system. Do not > click links or open attachments unless you recognize the sender and know the > content is safe. > > > I don't know if this is the case here, but it is possible to write a > program to run in addressing mode 64 but use 32 bit instructions so it > works inside the 4GB address range. > > On Fri, Nov 1, 2024 at 11:46 AM Tony Harminc <t...@harminc.net> wrote: > > > > On Fri, 1 Nov 2024 at 08:59, René Jansen <rvjan...@xs4all.nl> wrote: > > > > > Reading through the release notes (the "what's new") of the LLVM-Clang > > > based C/C++ compiler for z/OS I see support for 32-bit programs and > > > XPLINK32 linkage. Now I have to admit that I not followed all news closely > > > but I even have a hard time googling this. I thought there is 24-,31- and > > > 64-bit support on z/OS. Is this new and where can we read about this? > > > > > > > I don't think there's anything architecturally new here - "32-bit" is often > > used in the non-mainframe world as a contrast to "64-bit", and indeed even > > S/360 can be said to be a 32-bit architecture. It's only the way that > > address arithmetic and use works that uses 1 (21-bit) or 8 (24-bit) high > > address bits as flags. In 64-bit mode all bits are address bits, i.e. there > > is no 63-bit mode. > > > > More succinctly, it's "how wide are the registers", and perhaps "how big is > > a pointer in C"? > > > > Tony H. > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > -- > Mike A Schwab, Springfield IL USA > Where do Forest Rangers go to get away from it all? > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
