I covered these addressing modes in video #14 on the addressing modes in general, but I’ve had a couple of questions about the indirect modes specifically. I thought it might help to draw out examples on the whiteboard, since they are more complicated than the other modes. Hopefully watching this along with the examples in #14 will make it clearer. Indirect addressing, especially the Y-indirect (indirect indexed), is a powerful mode that lets you setup pointers into memory that can be adjusted on the fly, as we do with HEADP and TAILP in the worm program.
Video production notes: The quality on these still isn’t very good. Seems like there are either glares or shadows, so that’s something to keep working on. For the audio, I tried recording that on my phone in my shirt pocket, so the video camera didn’t have to try to pick it up from several feet away. Then it was just a matter of laying one over the other with ffmpeg and working out the timing.