Using MPFR types with GMP (mpfr with mpz)

[Flarp Emerald]

This is probably a really stupid question, but I need this for something
I'm working on.

Say I have a number, 10, and I need to divide it by 2^512. 2^512 is an mpz,
and the computation should return an MPFR type.

(until this point I've used CPP wrappers so if I get any names wrong I
apologize in advance)

Psudeo code -> (not using GMP functions)

mpz_class big = 2^512
mpfr_class precise = 10 / big

How would I go about doing this?