test-round.rs

fn main() {
    let mut failed = 0usize;
    for i in 0..=u32::max_value() {
        if i & 0xffffff == 0 { println!("{}", i); }
        let x = f32::from_bits(i);
        let r_std = x.round();
        let r_hoc = (x+0.5).floor();
        if r_std.to_bits() != r_hoc.to_bits() {
            println!("round for {} fails", x);
            failed += 1;
            if failed > 10 { break }
        }
    }
}