COBOL Manual for TNS and TNS/R Programs
Migrating TNS Programs to Native Programs
HP COBOL Manual for TNS and TNS/R Programs—522555-006
33-7
Misalignment Tracing Facility
In addition to HP COBOL, the data misalignment issue might affect programs that use
this NonStop software. If you use these products, see the appropriate document:
Topics:
•
Misalignment Tracing Facility
•
Misalignment Handling
•
Causes of Misalignment in HP COBOL Programs
Misalignment Tracing Facility
The misalignment tracing facility is enabled or disabled on a system-wide basis (that is,
for all processors in the node). By default, it is enabled (set to ON). It can be disabled
(set to OFF) only by the persons who configure the system, using the Subsystem
Control Facility (SCF) attribute MISALIGNLOG. Instructions are in the SCF Reference
Manual for the Kernel Subsystem.
When a misaligned address causes an exception that TNS processor product versions
prior to G06.17 would have rounded down, the tracing facility traces the exception.
While a process runs, the tracing facility:
•
Counts the number of misaligned-address exceptions that the process causes (the
exception count)
•
Records the program address and code-file name of the instruction that causes the
first misaligned-address exception
Product T Number Document
Accelerator T9276 Accelerator Manual Data Alignment Addendum
TNS C T9255 C/C++ Programmer’s Guide
TNS C++ T9541
TNS c89 T8629
TNS/R pTAL T9248 pTAL Reference Manual
TNS TAL T9250 TAL Programmer’s Guide Data Alignment Addendum
Note. HP recommends that the MISALIGNLOG attribute be left ON (its default setting) so that
any process that is subject to rounding of misaligned addresses will generate log entries,
facilitating diagnosis and repair of the code. Only if the volume of misalignment events affects
performance should this attribute be turned OFF.
Note. The tracing facility does not count and trace every misaligned address, only those that
cause round-down exceptions. Other accesses that use misaligned addresses without
rounding them down do not cause exceptions and are not counted or traced. Also, only a
periodic sample of the counted exceptions is traced using its own EMS event messages.