Also, examine the CP internal trace table to determine the events
that preceded the abnormal termination. Start with the last event
recorded in the trace table and read backward through the trace table
entries. The last event recorded is the last event that was completed.
The TRACSTRT field (locationX'OC') contains the address of the start
of the trace table. The TRACEND field (locationX'10') contains the
address of the byte following the end of the trace table. The address
of the next available trace table entry is found in theTRACCURR field
(locationX'14'). To find the last recorded trace table entry, subtract X'10' from the value at location X'14',. The result is the address of
the last recorded entry. Figure 8, earlier in this section, describes
the format of each type of trace table entry.Igte: If the system was in attached processor mode, the trace table
pointers are in absolute page zero.
REGISTERUSAGE In order to trace control blocks and modules, it is necessary to know
theCP register usage conventions.
The 16 general registers have many
operation. The following table shows
registers.
uses that vary depending upon the
the use of some of the general GR 1
GR 2
GR 6,7,8
GR10 GR 14,15
ContentsThe-virtual address to be translated.
The real address or parameters.
The virtual or real channel, centrol unit, and device
control blocks.
The address of the activeIOBLOK. The external branch linkage.
The following general registers usually contain the same information. GR 11
GR 12
GR 13
ContentsThe-address of the active iMBLOK. The base register for the module
The address of the current save
called via anSiC. executing.
area if the module wasUse these registers along with the CP control blocks and the data in
the prefix storage area to determine the error that caused theCP abend. SAVE AREA CONVENTIONS There are three save areas that may be helpful in debugging CP. If a
module was calledby an SVC, examine the SAVEAREA storage area. SAVEAREA is not in the PSA; the address of the SAVEAREA is found in
general register 13. If a module was called by a branch and link, the
general registers are saved in thePSA in an area called BALRS1VE (X'240'). The DMKFRE save area and work area is also in the PSI: these
areas are used only by the DMKFREE andDMKFRET routines. The DMKFRE save area (FREESAVE) is at location X'280' and its work area (FREEWCRK) follows at location X'2CO'.
that preceded the abnormal termination. Start with the last event
recorded in the trace table and read backward through the trace table
entries. The last event recorded is the last event that was completed.
The TRACSTRT field (location
of the trace table. The TRACEND field (location
address of the byte following the end of the trace table. The address
of the next available trace table entry is found in the
(location
the last recorded entry. Figure 8, earlier in this section, describes
the format of each type of trace table entry.
pointers are in absolute page zero.
REGISTER
the
The 16 general registers have many
operation. The following table shows
registers.
uses that vary depending upon the
the use of some of the general
GR 2
GR 6,7,8
GR
Contents
The real address or parameters.
The virtual or real channel, centrol unit, and device
control blocks.
The address of the active
The following general registers usually contain the same information.
GR 12
GR 13
Contents
The address of the current save
called via an
area if the module was
the prefix storage area to determine the error that caused the
module was called
general register 13. If a module was called by a branch and link, the
general registers are saved in the
areas are used only by the DMKFREE and