Igor Delovski Board

[delovski]

Apple: TN 1136: MicroBug: The ROM Debugger (PDF)


Force Quitting
If you want to force quit the current process, you can just type:
SM 0 A9F4G 0
This places an _ExitToShell trap at location 0 and then continues execution at that trap. Of course, this trick is now
mostly pointless because Mac OS supports the Command-Option-Escape key sequence to force quit a hung process.

Some enterprising souls have discovered that commands like:
G FINDER
G EXITTOSHELL
will also force quit an application. This is because MicroBug's expression evaluator is extremely forgiving, so seemingly
irrelevant strings will successfully evaluate to expressions. In both cases shown above, the resulting value is odd. Going to
an odd address causes the 680x0 microprocessor (or the emulated microprocessor, on PowerPC-based computers) to take
an "address error" exception. Mac OS responds to this exception by terminating the current process, which was the desired
result."

MicroBug and the Modem
If you crash into the debugger and the system hangs, try turning off your modem.

Quote:

Note: "I have no idea whether this is still useful advice, but how could I remove such a cryptic comment from the technote? -- 1998"

"This Note is directed at bored developers
looking for something historically interesting
to read on the train going home after a hard
day's coding. It's also directed at developers
trying to debug a problem that disappears
when they install MacsBug."