This may very well be the most epic post in HN history.
EDIT : I recall fondly algorithm D... one of my first programming experiences in the 90s was trying to implement knuth's arithmetic algorithms for addition, substraction, etc. in 8086 asm. Got them right up until long multiplication (that one was a tremendous effort). Algorithm D was too formidable to even dare me attempt. Feel extremely happy to see people in 2026 looking at these algorithms closely.