[JackFr]

> Processors are inherently awesome at branching, adding, adding, shifting, etc. And shifting to get powers of 2 (i.e., KB vs. GB) is a superpower of its own. They're a little less awesome when it comes to math.pow(), math.log(), and math.log() / math.log().

And here's something to consider -- if you're converting a number to human readable format it's more likely than not your about to do I/O with the resulting string, which is probably going to be an order of magnitude more expensive than the little function here.

[dmccarty]

Great point, I wish I'd mentioned it. The expense of the printf dwarfs the log / log (double divided by a double then cast to an int), which itself is greater than some repeated comparisons in a for loop.

It's key to be able to recognize this when thinking about performant code.

In other words, the entire exercise is silliness because the eventual printf is going to blow away any nanoseconds of savings by a smarter/shorter routine.