hfloat

hfloat (for huge floats) is a library package for doing calculations with floating point numbers of extreme precision. It is optimised for computations with 1000 to several million digits. The computations can be done in (almost) arbitrary radix. The library contains routines for addition, subtraction, multiplication, division, n-th power, square root, n-th root, logarithm, exponentiation and more. There are implementations of several superlinear converging algorithms for the computation of pi. The computation of 1 million decimal digits of pi takes about 15 seconds on an AMD64/2.2GHz. (Source: http://freecode.com/)