Writing Testbenches: Functional Verification of HDL Models first introduces the necessary concepts and tools of verification, then describes a process for carrying out an effective functional verification of a design. This book also presents techniques for applying a stimulus and monitoring the response of a design by abstracting the operations using bus-functional models. The architecture of testbenches built around these bus-functional models is important for minimizing development and maintenance effort. Behavioral modeling is another important concept presented in this book. It is used to parallelize the implementation and verification of a design and to perform more efficient simulations. For many, behavioral modeling is synonymous with synthesizeable or RTL modeling. In this book, the term `behavioural' is used to describe any model that adequately emulates the functionality of a design, usually using non-synthesizeable constructs and coding style. Writing Testbenches: Functional Verification of HDL Models focuses on the functional verification of hardware designs using either VHDL or Verilog. The reader should have at least a basic knowledge of one of the languages. Ideally, he or she should have experience in writing synthesizeable models and be familiar with running a simulation using any of the available VHDL or Verilog simulators. From the Foreword `With gate counts and system complexity growing exponentially, engineers confront the most perplexing challenge in product design: functional verification. The bulk of the time consumed in the design of new ICs and systems is now spent on verification. New and interesting design technologies like physical synthesis and design reuse that create ever- larger designs only aggravate the problem. What the EDA tool industry has continuously failed to realize is that the real problem is not how to create a 12 million gate IC that runs at 600 MHz, but how to verify it. This text marks the first genuine effort at defining a verification methodology that is independent of both tools and applications. Engineers now have a true reference text for quickly and accurately verifying the functionality of their designs.' Michael Horne, President and CEO, Qualis Design Corporation