"and SDWAPARM" would be more accurate. Thinking as a programmer, you would presumably get it from one *or* the other.
btw, I found that the address will be a freakishly low address, something like x'00000B00'. Do not be frightened. sas On Thu, Jun 22, 2017 at 9:29 AM, Greg Dyck <gregd...@pobox.com> wrote: > On 6/22/2017 4:17 AM, contactmura...@gmail.com wrote: > >> I am new to SRBs & FRRs. I have a question regarding FRR Parameter >> address discussed over here. >> >> When said "If the SRB abends, its FRR receives the address of the FRR >> parameter area in R2 (or SDWAPARM)." >> >> Why is it (or SDWAPARM)? That means the contents in R2 can't be trusted >> all the times and SDWAPARM always has the correct FRR parameter address no >> matter what is in R2? >> >> I am asking this question because of the below scenario. >> >> Suppose my SRB issues a system macro say, 'STORAGE OBTAIN' and for some >> reason it fails inside a system program. At that time, R2 might contain >> some ghost value. Before control reaches FRR, >> >> - Does the system restores the original contents of R2 that was at the >> time of >> entry into SRB? >> >> - OR in such cases R2 will be corrupted but at the entry point of FRR, the >> SDWAPARM field anyways contains the correct address of FRRPARM. >> >> Can someone please help me understand this. >> > > The current registers at entry to the FRR are set by RTM. They are *not* > the registers at the time of the error. The registers at time of error are > only found in the SDWA. > > RTM will *always* set R2 to point to the FRR 6 word parameter list > associated with the FRR prior to calling the FRR. The same value is also > stored into SDWAPARM by RTM. There is no guarantee, however, that *your* > program will have executed long enough to fill in any data in the parameter > list after the FRR was set. > > Regards, > Greg > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > -- sas ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
