prime

use packed_simd::*;

fn try_divide(size: i32) -> i32 {
    let mut primes = vec![f32x8::new(16777216f32, 16777216f32, 16777216f32, 16777216f32, 16777216f32, 16777216f32, 3f32, 2f32)];
    let mut sqr = 2;
    let max_sqr = f32::sqrt(size as f32) as i32;
    let mut pos: i32 = 8 - 3;
    let mut flag = true;
    let mut current = 5;
    let mut count = 2;

    while current <= size {
        let num = f32x8::splat(current as f32);
        if sqr * sqr <= current {
            sqr += 1;
        }

        for &divisor in primes.iter() {
            if num % divisor == f32x8::splat(0f32) {
                break;
            }
            if divisor.extract(0) as i32 >= sqr {
                count += 1;
                if current <= max_sqr {
                    *primes.last_mut().unwrap() = primes.last().unwrap().replace(pos as usize, current as f32);
                    pos -= 1;
                    if pos < 0 {
                        primes.push(f32x8::splat(16777216f32));
                        pos = 8 - 1;
                    }
                }

                break;
            }
        }

        flag = !flag;
        current += if flag { 4 } else { 2 };
    }

    count
}

fn main() {
    println!("{}", try_divide(100));
}