MONOTONE is a tracker and replayer for the original IBM PC, written in pascal:
https://github.com/MobyGamer/MONOTONE/
I've also written a replay routine for it into my (high end) audio engine:
https://github.com/jarikomppa/soloud/tr … e/monotone
Example tune:
https://www.youtube.com/watch?v=Uz59S3QN8dQ