Page of GC20-1S07-7 As Updated April 1, 19S1 by TNL GN25-0S29 3. Operator Pressinq SYSTEM RESTART Button on Processor Console
Examine the old PSi at location X'OS' to find the location of the
instruction that was executing when the operator pressed SISTEK RESTART. The operator presses when CP- is in a
disabled wait state or loop. The conditions that cause an abnormal termination of an
attached processor configuration are the same as those that cause a
uniprocessor configuration to abnormally terminate. bQ! The information in low storage specifies the
status of the system at the time CP terminated. Status information is
stored in the PSA. Iou should be able to tell the module that was
executing by looking at the PSA. Refer to the appropriate save (SAVEAREA# BALRSAVE, or FREESAVE) to see how that module started to
execute. The PSA is described in the 199if-publication. Examine the real and virtual control blocks to find the status of I/O operations. Fiqure 9 shows the relationship of CP Control Blocks.
Examine the CP internal trace This table can be extremely
helpful in determining the events that preceded the abend. The "CP Internal Trace Table" description tells you how to use the trace table.
The values in the general registers can help you to locate the
current IOBLOK and VMBLOK and the save area. Refer to "Reading CP Abend
Dumps" for detailed information on the contents of the general register-s. If the program check old PSi (PROPSW) or the SVC old PSW (SVCOPSW) points to an address beyond the end of the resident nucleus, the module
that caused the abend is a pageable module. Refer to "Reading CP Abend
Dumps" to find out how to identify that pageable module. Use the CP load
map that was created when the VM/370 system was generated to find the
address of the end of the resident nucleus. When CMS abnormally terminates, the following error message appears on
-the terminal: DMSABN14ST SYSTEM ABEND xxx CALLED FROM yyyyyy wher-e xxx is the abend code and yyyyyy is the address of the instruction
causing the abend. The DMSABN module issues this message. Then, CKS waits for a command to be entered from the terminal.
Because CMS is an interactive system, you will probably want to use
its debug facilities to examine status. You may be able to determine the
cause of the abend without taking a dump.
The d.ebug program is located in the resident nucleus of CMS and has
its own save and work areas. Because the debug program itself does not
alter the status of the system, you can use its options knowing that
routines and data cannot be overlaid unless you specifically request it.
Likewise, you can use the CP commands in debugging knowing that you
cannot inadvertently overlay storaqe because the CP and eMS storage
areas are completely separate. Part 1. Debugging with VM/370 19

April 1, 1981 fQR First determine the reason CMS abnormally
terminated. There are four types of CMS abnormal terminations:
1. Program Exception
control is given to the DMSITP routine whenever a hardware program
exception occurs. If a routine other than a SPIE exit routine is in
control, DMSITP issues the message DMSITP141T xxxxxxxx EXCEPTION OCCURRED AT xxxxxx IN ROUTINE xxxxxxxx
and invokes DMSABN (the abend routine). The abend code is
where x is the program exception number (0 through F).
possible programming exceptions are: o
1
2
3
4
5
6
7
8
9
A
B
C
D E F Meaning Imprecise
Operation
privileged operation
Execute
Protection
Addressinq
Specifica t ion
Decimal data
Fixed-point overflow
Fixed-point divide
Decimal overflow Decimal divide
Exponent overflow
Exponent underflow Significance Floating-point divide
2. ABEND Macro OCx, The
control is qiven to the DMSSAB routine whenever a user routine
executes the ABEND macro. The abend code specified in the ABEND
macro appears in the abnormal termination message DMSABN148T. 3. Halt Execution command (HX) Whenever the virtual machine operator signals attention and types HX, CMS terminates and types "CMS". 4. System Abend
A CMS system routine can abnormally terminate by issuing the DMSABN macro. The first three hexadecimal digits of the system abend code
type in the eMS abend message, DMSABN148T. The format of the DMSABN macro is:
r I I (label J DMSABN I I '---- code
(reg)
r r" I' IBALRII L L J,J 20 IBM VM/370 System proqrammer's