CMU Common Lisp supports IEEE denormalized floats. Denormalized floats provide a mechanism for gradual underflow. The Common Lisp float-precision function returns the actual precision of a denormalized float, which will be less than float-digits. Note that in order to generate (or even print) denormalized floats, trapping must be disabled for the underflow exception (see section 2.1.3.4.) The Common Lisp least-positive-format-float constants are denormalized.
[Function]
extensions:float-normalized-p x
This function returns true if x is a denormalized float. x must be a float.