#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

use Benchmark qw{cmpthese :hireswallclock};

my $n = 0x80061861;

say "and_rshift:    $n => ", join(' : ', and_rshift());
say "lshift_rshift: $n => ", join(' : ', lshift_rshift());
say "mixed:         $n => ", join(' : ', mixed());
say "mixed_assign:  $n => ", join(' : ', mixed_assign());
say "just_shift:    $n => ", join(' : ', just_shift());

cmpthese(-10, {
    and_rshift    => \&and_rshift,
    lshift_rshift => \&lshift_rshift,
    mixed         => \&mixed,
    mixed_assign  => \&mixed_assign,
    just_shift    => \&just_shift,
});

sub and_rshift {
    my $top14 = ( $n & 0xfffc0000 ) >> 18;
    my $nxt6  = ( $n & 0x0003f000 ) >> 12;
    my $mid6  = ( $n & 0x00000fc0 ) >>  6;
    my $bot6  = ( $n & 0x0000003f );

    return ($top14, $nxt6, $mid6, $bot6);
}

sub lshift_rshift {
    my $top14 = $n >> 18;
    my $nxt6  = $n << 46 >> 58;
    my $mid6  = $n << 52 >> 58;
    my $bot6  = $n << 58 >> 58;

    return ($top14, $nxt6, $mid6, $bot6);
}

sub mixed {
    return ($n >> 18, $n >> 12 & 0x3f, $n >> 6 & 0x3f, $n & 0x3f);
}

sub mixed_assign {
    my $top14 = $n >> 18;
    my $nxt6  = $n >> 12 & 0x3f;
    my $mid6  = $n >> 6 & 0x3f;
    my $bot6  = $n & 0x3f;

    return ($top14, $nxt6, $mid6, $bot6);
}

sub just_shift {
    return ($n >> 18, $n << 46 >> 58, $n << 52 >> 58, $n << 58 >> 58);
}