It's easy when you can do logarithms (and multiplications and exponentials) to high precision, which is quite easy in itself. I think this is how Alpha does it.

This was not as obvious a few years ago (well, more like 10 or 15 now), most people simply used hardware computations for floating point numbers, which limits precision. Once you implement floating point numbers in software, which started to make sense at some point, you can simply choose a higher precision.