As suggested by @nettles, I've implemented full auto sprite flipping to #varvara. It doesn't seem to impact any roms negatively, but instead of writing your own sprite flipping routine, you can make use of this to draw entire rows/cols at a time.

A side-effect is that right-to-left, and bottom-to-top, font drawing can make use of the auto byte, which had always been lacking.

implementation: https://git.sr.ht/~rabbits/uxn11/tree/main/item/src/devices/screen.c#L181

test: https://git.sr.ht/~rabbits/uxn11/tree/main/item/etc/pict.tal

mailing list: https://lists.sr.ht/~rabbits/uxn