Arbitrary precision arithmetic with Ruby

Question

How the heck does Ruby do this? Does Jörg or anyone else know what\'s happening behind the scenes?

Unfortunately I don\'t know C very well so bignum.c is of little

Answer 1

I don't know of the implementation details so I'll cover how a basic Big Number implementation would work.

Basically instead of relying on CPU "integers" it will create it's own using multiple CPU integers. To store arbritrary precision, well lets say you have 2 bits. So the current integer is 11. You want to add one. In normal CPU integers, this would roll over to 00

But, for big number, instead of rolling over and keeping a "fixed" integer width, it would allocate another bit and simulate an addition so that the number becomes the correct 100.

Try looking up how binary math can be done on paper. It's very simple and is trivial to convert to an algorithm.