HP 64782, User Manual, Page: 161 / 554

Using Execution Breakpoints
Breakpoints allow you to stop target program execution at a particular
address and transfer control to the emulation monitor. Suppose your system
crashes when it executes in a certain area of your program. You can set a
breakpoint in your program at a location just before the crash occurs. When
the processor executes the breakpoint, the emulator will force a break to the
monitor. You can display registers or memory to understand the state of the
system before the crash occurs. Then you can step through the program
instructions and examine changes in the system registers that lead up to the
system crash.
Execution breakpoints are implemented using the BKPT instruction of the
MC6833x. You can enable, disable, set, or clear execution breakpoints.
Set execution breakpoints at the first word of program instructions.
Otherwise, your BKPT may be interpreted as data and no breakpoint cycle
will occur. When the BKPT instruction is executed, target program
execution stops immediately (unlike using the analyzer to cause a break into
the monitor, which may allow several additional bus cycles to execute before
the break finally occurs).
This section shows you how to:
•
Set execution breakpoints in RAM.
•
Set execution breakpoints in ROM.
•
Use temporary and permanent breakpoints.
•
Enable and disable execution breakpoints.
•
Set a permanent breakpoint.
•
Set a ROM breakpoint in RAM.
•
Clear execution breakpoints.
•
Display status of all execution breakpoints.
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