Data Types in VHDL The syntax of object declaration as studied in the previous chapter is again revisited. Object_class Object_name : Object_data_type[:= Initial_value]; The essential component of the above declaration is object class and data type. Whereas the class signifies the class/category (signal, variable, constant, file) to which the object belongs, the data type gives an idea of the type (bit, Boolean, std_logic, integer etc.) -of the values an object may take and the value from a set of the values that an object may be assigned. Every given data type supports some specific operations for the object for example data type bit supports logical and arithmetic operations but std_logic (as given in std-logic_1164) does not support arithmetic operation. If arithmetic operation on std_logic