On Fri, 26 Feb 2016 22:48:43 -0600, Mike Schwab wrote: >On Fri, Feb 26, 2016 at 10:37 PM, Tom Marchant ><[email protected]> wrote: ><deleted> >> In addition, when an instruction references a storage >> location whose upper bits match the prefix register, those bits are replaced >> with 0. >> This last function of prefixing was not implemented on System/360 or the >> earliest >> system/370 models. >> ><deleted> >> -- >> Tom Marchant >About 1985-1989, I remember our mainframe taking a lot of crashes from >jumps to low address space on a 2 processor pre-XA machine. Was some >of this caused by this function?
I doubt it. Do you have a dump? IIRC, the address in the prefix register is the address of a page in SQA, and the any reference to that SQA page would result in accessing absolute page zero. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
