[evincarofautumn]

> except for the minor fact that the NaN types can in theory be represented by different bit sequences - in practise all the same are used

I can’t say it’s terribly common, but there’s always someone like me out there going “Ooh, 51 free bits! Don’t mind if I do.” It’s a common trick for value representation in implementations of dynamic languages.

Anyway, poor floating-point support is about as prevalent as poor Unicode support—the common cases seem to work, lulling you into a false sense of security before you discover that the edge cases are untested. I’ve seen bugs caused by a green thread getting rescheduled onto a different OS thread with a different rounding mode.