bcmath, standart ?

Hello, Currently need the modulo operator, the problem is % is limited to int in php (direct uses of the c operator after conversion to long), and is not enough for my needs (IBAN, BAN,... for Validate). Should I consider the bcmath ( or gmp) as a widely used module ? Or have I to use a php implementation of modulo ? note that works with a larger ranger, division in php can work with double as well as long. And it s funny to see a php function works and the native operator failed, normal but funny ;). pa