The pages on this site contain documentation for very old MS-DOS software,
purely for historical purposes.
If you're looking for up-to-date documentation, particularly for programming,
you should not rely on the information found here, as it will be woefully
out of date.
Error Message
Error 133: Real underflow
A floating-point operation produced an underflow. This
error only occurs if you are using the 8087 numeric
coprocessor with a control word that unmasks underflow
exceptions.