🎼 On the first day of Christmas, my debugger gave to me: a stack trace of SIGFPE 🎶
So anyway it turns out it's one of those historically misnamed things and I indeed didn't have mystery floating point math lurking in my integer snow code; it was a modulo operator getting a zero denominator due to unsigned overflow from a breezeline getting too old without being reset, which is random.
Wonder if new-age C++ will ever add saturating arithmetic to the core language.
Ah, because I am an arrogant fool using a chainsaw, I also casually had an operator[] kicking around rather than a nice safe at(), and there was *also* a sneaky out-of-bounds read that was pulling zeroes (and other forbidden numbers) from breezlines beyond the veil of defined reality.
