Yea, apparently AS is now being heavily used in its development. I need to look up the reference, but I read a while ago that AS-assisted ‘coding’ was used for making SMP work in Hurd. I’ve spent quite some time pondering my options now that OpenBSD, my former OS of choice, has been slowly but surely giving in to the hype, and I can tell you that currently the most sensible option seems to be (I’m not joking) 9Front.