A Gnu Sparc?

Electronic News, Feb 26, 2001 by Max Baron

Sunnyvale, Calif.

IT HAD TO HAPPEN SOONER OR later. Significant 32-bit microprocessor freeware is here; it has arrived as an implementation of SPARC and it is called LEON. The European Space Agency (ESA) has developed the 32-bit LEON, a SPARC V8-compatible core, for future space missions--SPARC in space. The core has been implemented as a highly configurable, synthesizable VHDL model and the ESA has made the processor's full source code freely available under the GNU LGPL license. ESA hopes the GNU approach will help promote the SPARC standard and enable development of system-on-a-chip (SOC) devices using SPARC cores.

Still marveling at SPARC's new-found life, let us consider the emergence of the free, open microprocessor as a genre and its impact on the future of intellectual property (IP) and semiconductor technology. Is the world ready to accept a free microprocessor? I think it is.

Firstly, the cost of proprietary IP is daunting for start-up companies. IP royalties might hinder sales of any product that is well into the commodity market window. Licensing fees and royalties have been made even more painful by the "consumerization" of the embedded market. Recently, cleanroom designs took a little bite out of this IP business as Lexra and Pico-TURBO offered MIPS and ARM compatibles with lower license and royalty fees.

Secondly, a soft core is welcome. With the emergence of competing foundries, soft cores are helping OEMs get the best deal and shortest time-to-market by moving from one foundry and/or process to another. Leading architectures are also now offered as soft cores. Configurable architectures can be offered only as soft cores.

Thirdly, for many applications, frequency, performance, and even power dissipation need not be cutting edge; what many products need is an adequate processor that has decent development tools--an engine that's good enough to run the operating system to control and coordinate the other components.

There are, however, a few clouds in the sky, suggestive of the beginnings of GNU software tools. Technical support and continued development don't go well with "free."

In the meantime, system designers need to evaluate the risks and rewards of using a free engine. No up-front license fees--that's saving a very large sum of money--and no royalties--which translates to more profit: these benefits vs. the need for more resources, more validation, and the greater development risk that can lengthen time-to-market.

The clouds have a silver lining, or the beginning of one. Metaflow, a company that has considerable microprocessor experience with several architectures, including SPARC, has offered its design services to create complete SOCs with LEON cores. Other design groups will undoubtedly follow Metaflow's example if the demand is high enough. And maybe an additional piece of encouraging data: LEON fits in one of each of Altera Corp.'s or Xilinx Inc.'s PLD chips. Other architectures' simple cores will also fit.

For the sake of completeness, Nios, a soft proprietary architecture core offered by Altera (nasdaq: ATLR) on PLD, is license-free, but will require royalty fees. Traditional business conditions are expected of PowerPC, Xtensa, ARC, MIPS, and ARM, which have also made the PLD scene.

Roadmap-wise, introduction of additional GNU LGPL engines is unlikely to come from groups that won't survive without license and royalty revenues. Most probably, new free cores will come from large organizations or academic bodies that are either well funded or have the advantage of time and do not compete in the market.

Support and development roadmap notwithstanding, a synthesizable free microprocessor is a timely challenge for the expert. It is modifiable and extensible, and in the hands of capable engineers, it can be developed, extended, and debugged beyond the proprietary walls normally erected around classical architectures.

It's not very likely that these new free engines will replace the cores that require license and royalty payments. Extreme results in design must still be hand-tuned, whether for performance, power dissipation, or wide and multiple datapaths and deep pipelines. But a sizable number of volume applications don't need the extremes, and that situation will establish the free cores.

Max Baron is editor-in-chief of the Microprocessor Report, an industry newsletter published by Cahners MicroDesign Resources.