[David] > Has anyone actually ever used those available bits for the zillions of NaNs > for > anything good?
Yes: in Python, many sample programs I've posted cleverly use NaN bits to hide ASCII encodings of delightful puns ;-) Seriously? Not that I've seen. The _intent_ was that, e.g., quiet NaNs could encode diagnostic information, such as the source code line number of the operation that produced a qNaN. But I don't know that anyone ever exploited that. Signaling NaNs were even more quixotic. For example, in theory, an implementation _could_ reserve some range of sNaN bit patterns to mean "the lower 20 bits are an index into a table of extended precision values", and a trap handler could catch the signal when the sNaN was used, and do extended-precision calculation in software, store the result in the table, and return an sNaN containing the result's index (or a regular double if the result fit in the format). In short, the kinds of things hardware designers think software would love ;-) _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/4Q4TF27MZNHDPCLW4QLEVLWXHXCVW6RK/ Code of Conduct: http://python.org/psf/codeofconduct/
