Function big_uint_to_sfixed 

pub(crate) fn big_uint_to_sfixed(
    uint: &BigUint,
    num_bits: u64,
    lg_scaling_factor: i64,
) -> String

Convert a BigUint to a string interpreted as signed fixed point value.

The output is equivalent to as_signed(uint) / (2 ** lg_scaling_factor) (without integer truncation through division) where as_signed() interprets the uint as a signed value using two’s complement.