Run-length video
This code from block 1188 is loaded into node 709. It's a video option I'm finding increasingly useful. The duration of dark is followed by the duration of bright, in unexts. This provides full-screen resolution (1024 pixels) since a scan line is some 9000 unexts.
sol
Writes to up to wait for the Start-of-Line pulse.
run
An infinite loop:
- Fetches from down (609)
- If negative, end-of-line
- Otherwise, delay
- Send dark or bright to io whichever wasn't sent before. over alternates the 2 brightnesses on the stack. An even number of dark-bright pairs is required. Dark followed by 0 bright produces a nice dot.