gmp precision

hi there.... i'm trying to use gmp functions to compute a square root.... i need the decimal part, but the gmp functions, at least afaik, implemented in php only return the integer part... i found no way to get this with gmp... i used bcmath functions for that, but i found they are 15 to 20 times slower.... will future releases of php implement gmp decimal functions or should i write a C cgi? regards s.