use Benchmark;
 
sub xor_swap
{
    my($num1x,$num2x) = @_;
    $num1x ^= $num2x; $num2x ^= $num1x; $num1x ^= $num2x;
}
 
sub perl_swap
{
    my($num1x,$num2x) = @_;
    ($num1x,$num2x)=($num2x,$num1x);
}
 
timethese (1_000_000, {
    xor_swap => sub { xor_swap(38,970); },
    perl_swap => sub { perl_swap(38,970); }
});