Hardware design is becoming indistinguishable from software design, necessitating a rapid shift to hardware modeling using C++. All thatýs lacking to make this market move is a coherent standard to jump-start design and EDA innovation.

A fundamental change in hardware design is occurring as design activity increasingly shifts to a higher level. In fact, the majority of hardware presently begins life as an abstract representation in C or C++ýnot Verilog or VHDL. Recoding these high-level representations in a common HDL prior to synthesis creates a significant ýdesign gapý that slows time-to-market since the design must be written twice, and introduces errors and uncertainty into what is already a risky enterprise.

Collett International estimates that more than 60 percent of all designs originate as C or C++ models. Experimenting with design tradeoffs is simply much more efficient using a high-level language than it is using an implementation language like Verilog or VHDL, and C++ represents the best choice thanks to its robustness, extensibility, and design-for-reuse heritage.

Designers lack a coherent and standardized method for representing hardware in C++. In fact, internal design teams have wrestled with this problem for years, and many C++ class libraries floating around do the job well enough but will never coalesce as a realistic standard. And without a standard way to represent hardware in C++, designers will never see a clean interface to design tools to take one of these abstract representations all the way to buildable gates.

To rally the industry around an open, non-proprietary C++ design standard, earlier this year we at Cynapps decided to offer our Cynlib class libraryýwhich lets users describe hardware features in C++ýas freely available, open-source software.

The industry can clearly benefit from a complete C++ hardware design environment. C++ became the most widely used language for software engineering because its object-oriented nature encourages code reuse. Objects can be verified once and then reused in different applications with only minimal changes.

Hardware design has increasingly become a software activity; design engineers spend more and more time at the front end of the process getting the algorithm right, and verifying it. Therefore, itýs only natural that the initial part of the design process be done in C++.

In addition, there is a vast amount of intellectual property already coded in C++, so if a designer wants to start something like an MPEG decoder or fax standard encoder, the odds are great that existing code can serve as a starting point. Add the fact that virtually all of todayýs engineering graduates already know how to program in C or C++, and the case for using it for hardware design is compelling.

Standard C++ is missing several features necessary to describe hardware, particularly a concurrency model, bit-accurate data types, reactivity to variable changes, and hierarchy. This is where a standard class library comes in, providing a set of C++ classes to implement these features. With Cynlib, for example, an architectural model can be iteratively refined from a very high level to a detailed implementation model. All the while the model is executable, so there is no discontinuous jump from one representation to another. At the lowest levels, the execution of the model provides a cycle-accurate simulation of the final hardware.

A building consensus suggests that using standard C++ class libraries is the logical next step in hardware modeling. Those class libraries used internally by system architects at various hardware companies typically receive sporadic support, and arenýt publicly available. At present, no open-source class libraries have both broad industry support and a solid company behind them. Open-source software like Cynlab can become a standard that much more quickly, as the entire community can review the code and participate in its evolution.

Cynapps is happy to compete based on the quality of its tools, not on its ability to defend a proprietary standard. Open-source licensing encourages the development of an easy-to-use, standard C++ class library for hardware modeling, while at the same time creating design environments that can unleash the unparalleled productivity potential of high-level design.