I am looking for a more efficient way of finding the Integer Square Root of a 128bit number... Need to use the NN Library one of the platforms I will use this on, has not enough memory for BigNum or MPZ void NN_SquareRoot(NN_DIGIT *output, NN_DIGIT *input, int digits) { NN_DIGIT divisor[NS*2], Temp[NS*2], Temp2[NS*2], Temp3[NS*2]; int t; int i; int g; unsigned char temp3[16]; NN_AssignZero(Temp2,NS); for(t=0;t