The BDM project on Sourceforge will provide BDM support for GDB. See
http://bdm.sourceforge.net/.
If you are debugging applications I suggest you use the uClinux gdbserver rather than BDM. If you are debugging the kernel then BDM may help but you need to know what you are doing. I once had some code in the BDM package to help GDB with some of the trap 0 (I think) in uCLinux. It may be needed and should be around in the version control for the BDM project.
Regards
Chris
