Debugging ! How do I debug GBA programs?

Hello! Im trying to write a GBA-game. I use the Mappy emulator, but I''ve got no idea of how to do source-level-debugging. How do I compile the .cpp files so Mappy gets some debug information ? I''ve tried with g++ -o main.elf -lm -g main.cpp ml_sprites.cpp objcopy --debugging -O binary main.elf main.gba but this results in : "objcopy: main.elf: no recognized debugging information" I''ve also tried g++ -o main.elf -lm -g -mthumb-interwork main.cpp ml_sprites.cpp objcopy --debugging -O binary main.elf main.gba and "-ggdb" instead of "-g", but nothing works. Can you tell me how I should do to debug my GBA-programs ? How should I compile them? (I use GCC3.0) Thanks (perhaps )