bitintr 0.2.0

#[macro_use]
extern crate bencher;

extern crate bitintr;

use bencher::Bencher;

fn u8_runner<F: Fn(u8) -> u8>(bench: &mut Bencher, f: F) {
    let mut vs: [u8; std::u8::MAX as usize] = [0; std::u8::MAX as usize];
    for i in 0..u8::max_value() {
        vs[i as usize] = i;
    }
    bench.iter(|| {
        for v in &mut vs.iter_mut() {
            *v = bencher::black_box(f(bencher::black_box(*v)));
        }
    })
}

fn rbit_u8_3_impl(x: u8) -> u8 {
    ((((x as u64) * 0x0202020202u64) & 0x010884422010u64) % 1023u64) as u8
}

fn rbit_u8_4_impl(x: u8) -> u8 {
    (((((x as u64) * 0x80200802u64) & 0x0884422110u64) * 0x0101010101u64)
        >> 32) as u8
}

fn rbit_u8_7_impl(x: u8) -> u8 {
    ((((((x as u32) * 0x0802u32) & 0x22110u32)
        | (((x as u32) * 0x8020u32) & 0x88440u32)) * 0x10101u32) >> 16)
        as u8
}

fn rbit_u8_bitintr(bench: &mut Bencher) {
    u8_runner(bench, |x| {
        bencher::black_box(bitintr::arm::v7::rbit(x))
    })
}

fn rbit_u8_3(bench: &mut Bencher) {
    u8_runner(bench, |x| bencher::black_box(rbit_u8_3_impl(x)))
}

fn rbit_u8_4(bench: &mut Bencher) {
    u8_runner(bench, |x| bencher::black_box(rbit_u8_4_impl(x)))
}

fn rbit_u8_7(bench: &mut Bencher) {
    u8_runner(bench, |x| bencher::black_box(rbit_u8_7_impl(x)))
}

benchmark_group!(
    rbit,
    rbit_u8_bitintr,
    rbit_u8_3,
    rbit_u8_4,
    rbit_u8_7
);
benchmark_main!(rbit);