Functions must be called by other statements
Parameters use positional association
ARCHITECTURE behavior OF adder IS
result <= add_bits(x, y);
This example illustrates the use of a function call in a signal assignment statement where the value returned by the function add_bits() is assigned to the signal result. Also note that the parameters passed to the function during the call are associated either by position (as in the example above) or by name. In this example, x is associated with parameter a, and y is associated with parameter b.