First, make sure you have gcc, ruby and Merlin32 installed. You need to prepare a YAML file to tell champ about all source and object files and their memory locations.
We specified some source files (they'll get compiled automatically) and some object files along with their locations in memory (`load`). We also specified the entry point for our program (`entry`), this can be a label or an address.
Furthermore, we can disable subroutines by replacing the first opcode with a RTS (`instant_rts`). This is necessary in some cases because Champ does not emulate hardware and thus can not load data from disk, for example.
This will run the emulator and write the HTML report to `report.html`. If you do not specify the maximum number of frames, you can still cancel the emulator by pressing Ctrl+C at any time. If you need fast results and don't need the animated GIF of all frames, specify the `--no-animation` flag, which will still give you all the information but without the animation.
By the way, there's a full-fledged, incremental, standalone, no-dependencies GIF encoder in `pgif.c` that writes animated GIFs and uses some optimizations to further minimize space. It's stream-friendly and as you feed pixels in via `stdin`, it dutifully writes GIF data to `stdout` until `stdin` gets closed.