The attached patch is to offer the functionality
desired by feature request: python.org/sf/491033

On machines that use standard IEEE floating point
doubles, the 'infinity' needs only to be 1e16 due to
the limited precision of floating point.  1e309 is used
for convenience sake, and will continue to be a
precision infinity until 1024 bits of precision in
floating point values is available.  At such point in
time where 1e309 is available in hardware, it will
still sufficient due to the practical limitations of
counting.