On windows I get "arithmetic error DIVISION-BY-ZERO signalled" when calling (asin 1) or (acos 1).

Unfortunately I couldn't jump to the source, but reading throuhg https://github.com/sbcl/sbcl/blob/master/src/code/irrat.lisp I saw
    (declaim (inline %asin))
    (defun %asin (number)
      (%atan (/ number (sqrt (- 1 (* number number))))))
which would explain the error. I'm not certain this is the code-path taken in my case but I guess this bug is easy enough to check to report it like this.

Regards, Paul