#!/usr/bin/env /friends/.rakudobrew/bin/perl6
use v6;
my Num $finish  = Num(@*ARGS ?? @*ARGS[0] !! 2.0);
die if +$finish == 0;
my Str $format = '%.17g';
my Num $d = $finish / 2;
my Num $f = $d;
for 0..53 {
    my Str $s = ~$d;
    die "Round trip failed for {$d}: off by {+$s - $d}" if +$s != $d;
    say sprintf "%s = 0x%sp0", $s, $d.base(16,16);
    last if $d == $finish;
    $f /= 2, $d += $f
}