Fib

Type Function: DINT

Input X	INT (input)
Output	DINT (Fibonacci numbers)
FIB calculate the Fibonacci number The Fibonacci number is defined as follows
	FIB(0) = 0, FIB(1) = 1, FIB(2) = 1, FIB(3) = 2, FIB(4) = 3, FIB(5) = 5 .....
	The Fibonacci number of X is equal to the sum of the Fibonacci numbers of X-1 and X-2. The function can compute the Fibonacci numbers up to 46, if X < 0 or greater than 46, the function returns -1.