This package extends the \xinteval syntax to do algebra in Q(phi) (where phi is the golden ratio), and compute Fibonacci numbers, Zeckendorf representations of positive integers and Bergman phi-representations of the positive elements of Z[phi]. The $ character is used to compute the Knuth Fibonacci multiplication. Being based upon xintexpr, it allows to compute with ``arbitrarily'' big integers, the reasonable use being with integers of at most a few hundreds of digits.