The Designer's Guide to VHDL, 2nd Edition

14 Generate Statements

Many digital systems can be implemented as regular iterative compositions of subsystems. Memories are a good example, being composed of a rectangular array of storage cells. Indeed, VLSI designers prefer to find such implementations, as they make it easier to produce a compact, area-efficient layout, thus reducing cost. If a design can be expressed as a repetition of some subsystem, we should be able to describe the subsystem once, then describe how it is to be repeatedly instantiated, rather than describe each instantiation individually. In this chapter, we look at the VHDL facility that allows us to generate such regular structures.

14.1 Generating Iterative Structures

We have seen how we can describe the implementation ...