This is a general issue for any debugger; stepping only works for the main
line, and does not handle exits. You can set a breakpoint on the exit, or use
the code
MYEOD XR 1,1
BR 14
Is there an RFE for the debugger to trap Instruction Fetch PER events?
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
עַם יִשְׂרָאֵל חַי
נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר
________________________________________
From: IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU> on behalf
of David Eisenberg <deisenbe...@optonline.net>
Sent: Thursday, May 9, 2024 8:18 AM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Does the GET macro indicate EOF?
>What are you trying to do?<
I'm trying to overcome a limitation in ASMIDF involving single-stepping through
code while debugging. That's the only reason I'm asking about this.
As per the IBM documentation, ASMIDF's single-stepping process involves the
automatic placement and removal of breakpoints. To do accomplish that, ASMIDF
must predict the next executable instruction, so that it can set a breakpoint
on it. When the current instruction is a GET macro, ASMIDF doesn't have the
logic to dig out the EODAD and set a temporary breakpoint on that instruction;
it only sets the temporary breakpoint on the instruction immediately following
the GET.
My GET code is in an external subroutine that is called by other applications.
Any developer who single-steps into that subroutine never gets control back
from ASMIDF, because the GET loop reads to EOF, and (because there is no
automatic breakpoint set on the EODAD) the program runs to completion without
stopping.
The entire problem disappears if the EODAD is immediately after the GET,
because then the breakpoint will be set and honored in all cases. But if I do
it that way, then I have to know whether I reached that instruction because it
really is the EOF, or whether the GET returned a record.
I just don't know how to dig what I need out of any control blocks, or whether
that information is available. Does the GET return anything I can use? Maybe
via R1? Or is there something in the DCB to tell me if I've reached the EOF?
David
