On Wed, Oct 10, 2012 at 9:44 PM, Guido van Rossum
Anyway, as an indication of the amount of work, you might want to look at the fpectl module -- the module itself is tiny, but its introduction required a huge amount of changes to every place where CPython uses a double.
I would start from another end. I would look at decimal.py first. This is little over 6,400 line of code and I think most of it can be reused to implement base 2 (or probably better base 16) float. Multi-precision binary float can coexist with existing float until the code matures and accelerators are written for major platforms. At the same time we can make incremental improvements to builtin float until it can be replaced by a multi-precision float in some well-defined context.