use Math::BigInt;

my $operand = '0x123456789abcdef0123456789abcdef0';
my $mask    = '0x100000000f00000000000000000000f0';

print Math::BigInt->new($mask)->band($operand)->as_hex(), "\n";

##</code><code>##

my $anded = Math::BigInt->new($mask) & $operand;
print $anded->as_hex(), "\n";