Patents stir debate in configurable-processor arena
SAN MATEO, Calif. The U.S. Patent Office has granted two patents to Tensilica Corp., the vendor of configurable-CPU intellectual property said Monday (Nov. 11), claiming broad protection on the automatic generation of CPU hardware and compatible software development tools from an architectural description. The announcement is likely to trigger a debate between the Santa Clara, Calif., company and archrival ARC International (San Jose, Calif.) about the breadth of the patents, the existence of prior art and the process of configuring CPU cores and their associated compilers and assemblers. Another potential party to the debate may be the formidable legal department at Hewlett-Packard Co. (Palo Alto, Calif.), in defense of pioneering work done at HP Labs.
Beatrice Fu, Tensilica's vice president of engineering, said the patent applications were filed in 1998 and 1999, early in the company's history, and were granted in recent weeks. The applications cover broad aspects of the Tensilica development platform, and in particular the process of generating a hardware CPU core with software tools assemblers, compilers and simulation models guaranteed by construction to match the hardware.
"There are lots of people who can generate simulators, assemblers and compilers for a defined instruction set," Fu said. "But these patents cover generating the hardware design and the software tools together. That is unique."
The novelty was disputed by Andrew Haines, senior vice president of marketing at ARC. "We will naturally evaluate the Tensilica claims when we have an opportunity to look at them in detail," he said. "But I should point out that ARC has been shipping configurable processor IP [intellectual property] and its associated tools since 1996 before the existence of the Tensilica corporation and we have always been very thorough in protecting our work. I'm quite comfortable that we are protected by our patents. And in any case I believe that most claims in this field would find a considerable body of prior art, much of which would be ours."
ARC's development environment also produces correct-by-construction processor extensions and coordinated development tools, according to the company. The ARC software tools are built on the MetaWare platform, a widely used retargetable assembler, compiler and debugger environment. MetaWare is owned by ARC.
HP Labs, meanwhile, has spent years developing techniques for automatically generating very long instruction word (VLIW) processors and coprocessors from application code. HP's Pico project the acronym stands for Program In, Chip Out has been under way at least since the early days of joint development with Intel Corp. of the Itanium architecture. And HP has also been scrupulous about protecting its IP.
"In Pico, we use conventional profiling tools to manually identify loop nests that are key to the performance of an application," said Vinod Kathail, principal research scientist at the labs. "The Pico tools then automatically develop a VLIW engine with the right execution units to execute these loops efficiently, and model the resulting performance. If necessary, the tools will also generate a hardware coprocessor to execute a critical loop nest."
Kathail said that these same tools generate a machine description of the VLIW engine that is then fed to a retargetable compiler. In addition, if coprocessors are generated, the original source code is modified with code that initializes and calls the coprocessors at the appropriate points. Then the retargetable compiler is used to compile the modified source code for the new VLIW engine. Kathail had no comment on whether HP has any plans to productize the Pico system.
Such apparent conflicts among granted patents are not all that unusual given the volume of patent applications and the Patent Office's apparent inability to asses prior claims and prior art in any meaningful fashion. Disputes are generally resolved either by direct negotiation between the parties holding the conflicting patents or via litigation.
"Often what appears to be a broad patent may turn out to have very specific claims," ARC's Haines observed. "Or a claim may turn out to be so broad that it is ruled unenforceable."