I've spent some time thinking about how to improve the PIO program that runs our Super VGA out. Currently it requires one 16-bit value per pixel, delivered from one of two ping-pong buffers each 1280 bytes long. Loading these buffers with RGB pixels based on characters read from the text buffer takes quite a lot of CPU time. If we limit ourselves to just two colours for the entire screen, we can build a small look-up table and get all 640 pixels drawn into the buffer per scan-line using about...
