[Qemu-discuss] GDB

[Rick Hodgin]

Greetings!

I have set QEMU for i386-softmmu, and have written some custom apps which 
populate a floppy disk image with the boot sector, plus other custom programs.  
They all load properly and all is working as on a real 386 machine.  Fantastic!

I see that QEMU has GDB support to debug code running on its virtual CPU.

I have tried to set this up using:
qemu -gdb -S -m 64 -no-fd-bootchk -fda floppy.img

And QEMU returns:
"qemu: could not open gdbserver on device '-S'"

I'm not sure what this message is telling me.  According to this page 
(http://wiki.qemu.org/Documentation/Debugging), the -S option should halt the 
CPU at startup, allowing remote GDB connection.

I would like to use GDB on the same (or remote) machine and connect to the 
launched-but-paused QEMU instance, and then be able to resume and break on INT 
3 opcodes, or single-step through disassembly examining instructions, registers 
and memory contents.

Can somebody point me in the right direction?

Thanks and best regards,
Rick C. Hodgin