On Wed, 29 Mar 2017 17:24:04 +0300, Binyamin Dissen <bdis...@dissensoftware.com> wrote:
>On Tue, 28 Mar 2017 13:04:10 -0400 Steve Smith <sasd...@gmail.com> wrote: > >:>My understanding is that a "data space" is a z/OS construction, the >:>hardware has no such concept. There's no reason a "dataspace" couldn't >:>execute instructions as far as the hardware is concerned. Just connect the >:>DAT tables as the primary and fire away. Of course, you'd be programming >:>on the bare metal, with absolutely no OS support; implying the next >:>interrupt would blow you away. > >No more on the "bare" metal than any other code. I think that Steve's point was that there would be no system services available. >Interrupts do not use the >page0 based off of the STO (whichever) but use the absolute address in the >prefix register. The storing and fetching of old and new PSW use addresses in real page zero, not virtual page 0, so you are correct, the "STO" (which may not be a Segment-table origin) is not relevant. ALL references to real page 0 and 1 are transformed by prefixing to obtain the absolute address. Similarly, all references to the real page identified by the prefix register and the following page are transformed to absolute pages 0 and 1. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
