On Wed, 29 Mar 2017 14:08:50 -0500, Tom Marchant wrote: >On Wed, 29 Mar 2017 13:58:34 -0400, Steve Smith wrote: > >>It was, but Binyamin has a good point. I didn't consider that FLIH would >>be invoked in real mode, so the hypothetical data-space code could >>theoretically survive until or unless the system turns DAT on for something >>other than directly resuming your code. > >I think not. The SVC New PSW is fetched from real address X'01C0', >but I just had a look at that location on our system and the PSW there >contains 04040000 80000000 00000000 01BA3F00. That has T=1 so >DAT is on. In any case, your data space doesn't have an SVC New >PSW at location 1C0. Nor does it have any of the other 5 New PSWs.
And all of this discussion assumes that you can find a way to pass control to code that you put into that data space. Code that would not require any system services at all. And if you could, would the system be able to interrupt you to run something else? Maybe if your dispatcher was clever enough to allow it. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
