I've finally cracked the gdb+qemu puzzle, so now we can debug code running on the qemu moxie simulator!
The last little gotcha was that the simulated $pc wasn't being updated after single-stepping. This will get you nowhere fast! But it's all fixed now, and here's how it works...
$ qemu-system-moxie -s -S -kernel hello.x
This tells qemu to load our hello world program, hello.x. The "-s" option tells it to wait for a connection from GDB on port 1234. The -S option tells it to freeze on startup, and wait for a "continue" command from the debugger.
Now, in a different terminal, fire up moxie-elf-gdb on hello.x and connect to qemu like so:
(gdb) target remote localhost:1234
GDB and qemu should be talking now, and the debugger will report that
the sim is waiting on
__start, the entry point to our hello.x ELF
file. Put a breakpoint on
main, and hit 'c' to continue. You should be
debugging as usual now. I normally run moxie-elf-gdb within emacs in
order to get a nice UI, but invoking it from ddd or Eclipse should work
just as well.
Everything has been committed MoxieDev. Now it's time to enjoy this sunny day!