You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: fpu.rs
    path of file: ./repos/libscemu/src/emu
    
    the code of the file until where you have to start completion: use iced_x86::Register;

#[derive(Clone)]
pub struct FPU {
    st: Vec<f32>,
    tag: u16,
    stat: u16,
    ctrl: u16,
    ip
    
    pub fn get_env64(&self) -> Vec<u64> {
        let mut r: Vec<u64> = Vec::new();
        let mut r1: u64 = self.tag as u64;
        r1 <<= 16;
        r1 += self.ctrl as u64;
        r.push(r1);
        r.push(0xffff0000);
        r.push(0xffffffff);
        r.push(self.ip);
        r
    }