require Config;
if ($Config::Config{ivsize} < 8) {
if (blessed $num && $num->can('as_hex')) {
+ require Math::BigInt;
return "\xff\xff\xff\xff\xff\xff\xff\xff" if Math::BigInt->new('18446744073709551615') <= $num;
return "\x00\x00\x00\x00\x00\x00\x00\x80" if $num <= Math::BigInt->new('-9223372036854775808');
my $neg;