I *think* some z/OS services use the top halves of R14 to R1 as scratch pads.
Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tony Thigpen Sent: Wednesday, March 10, 2021 4:21 AM To: [email protected] Subject: Re: OC1 regs in log oddity That makes sense. I guess that R15 still contained some 'garbage' left by the OS when it initially loaded and branched to the program. Tony Thigpen Binyamin Dissen wrote on 3/10/21 12:50 AM: > If all top-halfs are zero, it skips them. > > On Wed, 10 Mar 2021 00:28:07 -0500 Tony Thigpen <[email protected]> wrote: > > :>I just noticed something I had not noticed before. > :> > :>I have a little test program that I am doing all sorts of things to see > :>how things work. So, of course, I am crashing it a lot. Sometimes even > :>on purpose using DC x'0000' instructions. > :> > :>What I have noticed is that the log shows the registers differently > :>sometimes. For example: > :> > :>SYSTEM COMPLETION CODE=0C1 REASON CODE=00000001 > :> TIME=00.40.10 SEQ=00137 CPU=0000 ASID=0034 > :> PSW AT TIME OF ERROR 078D0000 00008CD8 ILC 2 INTC 01 > :> ACTIVE LOAD MODULE ADDRESS=00007000 OFFSET=00001CD8 > :> NAME=COPYTPX > :> DATA AT PSW 00008CD2 - 4710B03A 00004D10 B0308F00 > :> GR 0: 00000000_00009018 1: 00000000_0000901F > :> 2: 00000000_00007604 3: 00000000_0000AFFC > :> 4: 00000000_00009018 5: 00000000_0000901F > :> 6: 00000000_00040000 7: 00000000_FD000000 > :> 8: 00000000_00009010 9: 00000000_80008036 > :> A: 00000000_0000AFE0 B: 00000000_00008CB0 > :> C: 00000000_40008010 D: 00000000_00008E98 > :> E: 00000000_000092A8 F: 7FFAEA00_00008CB0 > :>vs. the following: > :> > :>SYSTEM COMPLETION CODE=0C1 REASON CODE=00000001 > :> TIME=00.39.24 SEQ=00136 CPU=0000 ASID=0034 > :> PSW AT TIME OF ERROR 078D0000 00008CE4 ILC 2 INTC 01 > :> ACTIVE LOAD MODULE ADDRESS=00007000 OFFSET=00001CE4 > :> NAME=COPYTPX > :> DATA AT PSW 00008CDE - 8DE00A13 000047F0 B0A29680 > :> GR 0: 00000950 1: 009C36B0 > :> 2: 00007604 3: 0000AFFC > :> 4: 00009018 5: 0000901F > :> 6: 00040000 7: FD000000 > :> 8: 00009010 9: 80008036 > :> A: 0000AFE0 B: 00008CB0 > :> C: 40008010 D: 00008E98 > :> E: 000092A8 F: 00000000 > :> > :>The only difference is that 64 bit regs are shown if I have not done an > :>OPEN macro while 31 bit registers are shown if I have issued an OPEN macro. > :>Test code snipit: > :> > :>*DC X'0000' > :> OPEN (SNAPDCB,(OUTPUT)) > :> DC X'0000' > :> > :>The program in question is assembled AMODE=24,RMODE=24. > :> > :>OK, whats up with this? > > -- > Binyamin Dissen <[email protected]> > 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 [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
