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Using the Emulator
Setting execution breakpoints in RAM
Setting execution breakpoints in RAM
When you set an execution breakpoint in RAM, the emulator will place a
breakpoint instruction (BKPT) at the address you specified, and then read
that address to ensure that the BKPT instruction is there. The program
instruction that was replaced by BKPT is saved by the emulator.
When the breakpoint instruction is executed, the BKPT acknowledge cycle is
detected by the emulator, and the emulator causes a break to the monitor.
At this point, the emulator replaces the BKPT instruction with the original
instruction it saved. It also replaces the BKPT instruction with the original
instruction whenever you disable or remove the breakpoint.
The emulator allows an unlimited number of breakpoints to be set in RAM.
Using temporary and permanent breakpoints
When you set a temporary execution breakpoint, the emulator creates the
breakpoint as described in the preceding paragraphs. When the breakpoint
instruction is executed, the emulator breaks to the monitor and removes the
breakpoint. Now you can execute that portion of program code as often as
you like and the breakpoint will not occur again, unless you enable it again.
When you set a permanent breakpoint, the emulator will process it the same
as a temporary breakpoint, but when the breakpoint instruction is executed,
the original instruction will only replace the breakpoint instruction during its
next execution. This allows you to step through the original instruction one
time. After your first step, the BKPT instruction will replace the original
instruction again so that the breakpoint will occur the next time the
breakpoint address is hit.
Permanent breakpoints remain in effect until you explicitly disable or remove
them.
Permanent breakpoints are available when using version A.04.00 or greater of
the emulation system firmware.
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