The discussion on Abstract Data Types is adapted from:
Sidhatha Mohanty, V. Krishnaswamy, P. Wilsey, "Systems Modeling,
Performance Analysis, and Evolutionary Prototyping with Hardware
Description Languages," Proceedings of the 1995 Multiconference on
Simulation, pp 312-318.
Abstract data types (ADTs) are objects which can be used to represent
an activity or component in behavioral modeling. An ADT supports data
hiding, encapsulation, and parameterized reuse. As such they give
VHDL some object-oriented capability.
An ADT is both a data structure (such as a stack, queue, tree, etc.)
and a set of functions (i.e. operators) that provide useful services
on the data. For example, a stack ADT would have functions for
pushing an element onto the stack, retrieving an item from the stack,
and perhaps several user-accessible attributes such as whether the
stack is full or empty.
