#!/usr/bin/perl

use strict;
use warnings;

sub bitstring {
   return undef unless $_[0] =~ /^\d*$/;
   my $bstr = unpack("B*", pack("L",$_[0]));
   sprintf ( "%s%s%s%s", substr($bstr, 24, 8), 
                         substr($bstr, 16, 8), 
                         substr($bstr, 8, 8),
                         substr($bstr, 0, 8)); 
}
print "21098765432109876543210987654321\n";
print bitstring(3)."\n";
print bitstring(254)."\n";
print bitstring(255)."\n";
print bitstring(256)."\n";
print bitstring(65534)."\n";
print bitstring(65535)."\n";
print bitstring(65536)."\n";