HP 64783A, User Manual

Page: 277 / 816

You may have several program modules that write to a variable, and sometime
during execution of your program, that variable gets bad data writen to it. Using a
prestore measurement, you can find out which module is writing the bad data.
Store-qualify writes to the variable, and use prestore to capture the instructions that
caused those writes to occur (perhaps by prestoring program reads).
Examples
Specify a prestore qualifier:
trace prestore address not range gen_ascii_data thru
gen_ascii_data
end status prog and read only
long_aligned gen_ascii_data
Disable prestore qualification:
trace prestore anything
To trace activity leading up to a program halt
•
Choose Trace
→
Until Stop.
•
Using the command line, trace on a program halt by entering:
trace on_halt
The above commands cause the analyzer to continuously fill the trace buffer until
you issue a Trace
→
Stop or stop_trace command.
Sometimes you may have a program failure that can’t be attributed to a specific
trigger condition. For example, the emulator may access guarded memory and
break to the monitor. You want to trace the events leading up to the guarded
memory access but you don’t know what to specify for a trigger. Use the above
command. The analyzer will capture and record states until the break occurs. The
trace list will display the last processor states leading up to the break condition.
Note that the "trace until stop" command may not capture the desired information
when you are using a foreground monitor (unless the code that causes the break
Chapter 5: Using the Emulation-Bus Analyzer
Making Complex Trace Measurements
247