#![feature(test)]

extern crate test;

use std::time::{Instant, Duration};
use test::black_box;

pub fn iterate() -> u32 {
    #[inline(never)]
    fn inner() -> u32 {
        let divisor: f32 = black_box(5.25);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32);
        black_box(black_box(25.0 / divisor).round() as u32)
    }

    black_box(inner());
    black_box(inner());
    inner()
}

pub fn main() {
    const PERIOD: Duration = Duration::from_nanos(558);

    let start = Instant::now();

    let mut cycles: u32 = 0;
    let mut offset = Duration::from_nanos(0);
    let mut missed = 0;

    loop {
        cycles += iterate();

        if cycles >= 5000000 { break; }

        let target = start + offset + (PERIOD * cycles);
        let mut now = Instant::now();

        if now < target {
            while now < target {
                now = Instant::now();
            }
        } else {
            offset += now - target;
            missed += 1;
        }
    }

    println!("{}", missed);
}