Control registers (if available) Program Status Word
TheSTORE STATUS command can save certain information contained in low
storage.
When debugging, you may find it advantageous to alter storage, registers, or thePSW and then continue execution. This is a good procedure for testing a proposed
change. Also, you can make a temporary correction and then continue to ensure
that the rest of execution is trouble-free. A procedure for using theSTORE ST A TUS command when debugging is as follows:
Issue theSTORE STATUS command before entering a routine you wish to
debug.
When execution stops (because an address stop was reached or because of
failure), display the extended logout area. This area contains the status that
was stored before entering the routine.
IssueSTORE STATUS again and display the extended logout area again. You
now have the status information before and after the failure. This information
should help you solve the problem.
Altering the Contents of Real StorageUse the STCP command to alter the contents of real storage. The STCP command
cannot alter the realPSW or real registers.
Modifying or Dumping CMS MODULE, LOADLIB, or TXTLIB FilesUse the ZAP command to modify or dump MODULE, LOADLIB, or TXTLIB
files. ZAP can be used to modify either fixed-or MODULE files. ZAP makes use of control records to control processing. These records can be
submitted either from the terminal or from a disk file.Using the VER and REP control records, you can verify and replace records or instructions in a control sec
tion (CSECT).Using the DUMP control record, you can dump all or part of a
CSECT, an entire member of aLOAD LIB or TXTLIB file, or an entire module
file. For a complete description of theZAP command, see the VM / SP Operator's
Guide.
Debugging CP in a Virtual Machine
CP Internal Trace Table
ManyCP problems can be isolated without standalone machine testing. It is possi
ble to debugCP by running it in a virtual machine. In most instances, the virtual
machine system is an exact replica of the system running on the real machine. To
set up aCP system on a virtual machine, use the same procedure that is used to
generate aCP system on a real machine. However, remember that the entire pro
cedure of running service programs is now done on a virtual machine. Also, the
virtual machine must be described in the realVM/SP directory. See VM / SP Oper
ating Systems in aVirtual Machine for directions on how to set up the virtual
machine.CP has an internal trace table that records events that occur in the real machine.
The events that are traced are:
External interruptions
SVC interruptions
Introduction to Debugging501
The
storage.
When debugging, you may find it advantageous to alter storage, registers, or the
change. Also, you can make a temporary correction and then continue to ensure
that the rest of execution is trouble-free. A procedure for using the
Issue the
debug.
When execution stops (because an address stop was reached or because of
failure), display the extended logout area. This area contains the status that
was stored before entering the routine.
Issue
now have the status information before and after the failure. This information
should help you solve the problem.
Altering the Contents of Real Storage
cannot alter the real
Modifying or Dumping CMS MODULE, LOADLIB, or TXTLIB Files
files. ZAP can be used to modify either fixed-or
submitted either from the terminal or from a disk file.
tion (CSECT).
CSECT, an entire member of a
file. For a complete description of the
Guide.
Debugging CP in a Virtual Machine
CP Internal Trace Table
Many
ble to debug
machine system is an exact replica of the system running on the real machine. To
set up a
generate a
cedure of running service programs is now done on a virtual machine. Also, the
virtual machine must be described in the real
ating Systems in a
machine.
The events that are traced are:
External interruptions
SVC interruptions
Introduction to Debugging