Diagnostic data

Data is formatted as it is written. No offline formatting of the trace data is required.

Trace point identifiers

The FP trace captures module flows, and at certain points, logic flows within modules. In most cases, there is a trace point at entry to a module and another at exit from the module. There might be additional trace points within the module. Each trace point has a unique 4-character identifier. To indicate nesting within call flows, using this unique 4-character identifier, the identifier is shifted right at each level. Each trace entry is prefixed by the identifier located in columns 1-13. The relative position of the identifier within columns 1-13 indicates nesting level, for example:

IRC1.........
.MCL0........

Because the identifier has 4-characters and 13 positions are available, 9 levels of nesting are possible. Output lines with no identifier in columns 1-13 are continuations of the previous entry. The module entry and exit trace entries differ by only one character. Usually, the module exit identifier is the same as the module entry identifier, except for one character. Normally, the first character of the identifier is shifted up one alphabetically, for example:

.MCL0........
.NCL0........

Trace point time stamps

Trace point time stamps are labeled with TOD=xxxxxxxx. The hexadecimal digits are the middle 4-bytes of an 8-byte STCK time stamp. The high order digit is approximately 1 second.

Note: Fields that are labeled TIME and DATE within trace entries refer to the compile date and time of the module involved, and are not related to trace time.

Trace initialization entries

Entries COT1 to TRAN at the beginning of the trace file refer to FP Trace initialization and can be ignored. These entries are produced if a FPTRACE DD statement is specified, even if the trace is not enabled.

Key trace point data items

The data that is traced for each trace point varies. However, each field has a label to make it easier to determine the contents of the entry. Some of the common and useful labels include:

Ra#b,Rab,: Registers a-b follow.
CALL: DL/I call function.
TOKN: UOR recovery token.
MODU: Module entry point address.
EPST: EPST address of the dependent region.
SSA: The first 30 bytes of the call SSA. Might contain residual data for short SSAs.