> IBM could easily pass PARAM= pointer to ETXR but I believe they intentionally
> chose not to do so because of storage lifecycle problems.
I would guess that it is an OS/360 interface, so I don't know what they
were thinking back then. I would be in favor of a PARAM to ETXR,
but it's not likely that I will get around to doing it, and the most
experienced ATTACH person is retiring.
> TCBFSA contains the first R13 pointer (18 fullwords).
It has been a 144-byte save area since at least z/OS 1.6 (20 years ago).
>Jim Mulder wrote on 10/17/2024 9:21 PM:
>> R14 to return is the only one that you need, and even that just points to
>> the SVC 3 instruction in the CVT.
>Even if you don't read dumps, someone has to read the dump will thank you. For
>debugging purposes, you will want to retain registers with documented known
>values from attach. R1-save is the PARAM= address. R13-prev should be 0 so
>you know you reached the end of the savearea chain. R13-next should >point to
>the next savearea or 0. R14-save is return address. R15-save is the entry
>point.
I was just stating what is actually required. I am well aware of what is
useful for debugging purposes, having made a living mainly by reading dumps for
45 years.
Jim Mulder
