As I believe that it gets control via SYNCH(X), you really do not need to save or restore any registers. Just exit by branching to the address that was contained in R14 when entered.
It would be a bit of an integrity exposure for the task termination routine to trust your registers. On Tue, 29 Aug 2017 06:02:12 -0400 Thomas David Rivers <[email protected]> wrote: :>When you specify the EXTR= parameter on an ATTACH, you :>are indicating the offset of an exit to asynchoronously receive :>control when the sub-task ends. :> :>This exit is invoked as many are, in that a 72-byte save area :>is addressed by R13 for saving/restoring the registers. :> :>The documentation even goes on to say: :> :> "The exit routine is responsible for saving and restoring :> registers". :> :>In the 'MVS Programming: Assembler Services Guide" in the :>section on linkage, called "Saving the calling program's registers" :>it says that saving registers involves saving R2 through R13 :>"Unless otherwise defined by the individual interface". :> :>Has the one sentence in the EXTR description 'otherwise defined' :>that R14,R15,R0 and R1 also need to be saved; or is it referring :>tot he normal saving which would not preserve those? It seems :>a little ambiguous to me. :> :>That is - in the case for an EXTR exit - do we need to also save/restore :>R14,R15,R0 and R1 - or are those "safe" to trash? I'd like to use :>them to trampoline into a different environment if possible without :>having to do a "save-area dance". :> :> - Thanks - :> - Dave Rivers - -- 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
