HP 64783A, User Manual

Page: 690 / 816

If any stacking or vector-fetch cycles are not terminated, the monitor will terminate
them by force. If this happens, the PC and SR may be displayed incorrectly by the
monitor. The same problem can result from stack memory that is not writeable.
Neither condition will prevent entry into the monitor, but you will not be able to
resume execution in the target program.
Exiting the foreground monitor
If the tests of the preceding paragraphs operate correctly, you should be able to
resume execution of the target program. You may want to take a trace of the
monitor exit to verify that everything is working correctly. Use the run command:
r
Software breakpoint entry into the foreground
monitor
The foreground monitor can also be entered via a software breakpoint. The
emulator will respond to any software breakpoint instruction in the code if
breakpoints are enabled, regardless of whether the breakpoint was inserted by the
emulator or not. Breakpoints are enabled by the following command:
bc -e bp
Only set breakpoints on the initial word of an instruction; otherwise, they will not
be executed, and they may alter an instruction, unintentionally. The emulator can
place a breakpoint using two methods. By default, the emulator will attempt to
modify memory to insert a breakpoint instruction at the address specified. If the
memory at the address specified is ROM or cannot be modified for some other
reason, special hardware resources on the emulator will interject a breakpoint
instruction when the associated address is fetched. You can tell if a hardware
resource was required to support a breakpoint by viewing memory at the breakpoint
address. If the BKPT instruction has replaced the normal instruction at that
address, a software breakpoint was used. If the normal instruction is still in the
Chapter 18: Connecting the Emulator to a Target System
Installing Emulator Features
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