Santa Cruz, Calif. Behavioral synthesis is finding renewed interest after a long drought, and one small provider now finds itself in a market that's heating up. Nine-year-old Y Explorations Inc. (Lake Forest, Calif.) has just announced enhancements to its Excite synthesis tool, which works from untimed ANSI C-language input.
Founded to commercialize research from the University of California at Irvine, Y Explorations (www.yxi.com) has shipped Excite since 1998, mostly for embedded-software and FPGA development.
Once trumpeted as the next big move in EDA, behavioral synthesis which works at a higher level of abstraction than RTL logic synthesis fell into disrepute in recent years as available products failed to provide sufficient quality of results. Synopsys Inc. pulled its Behavioral Compiler product off the market earlier this year, and market research firm Gartner Dataquest Inc. said the behavioral-synthesis tools market dwindled to $2.5 million in 2001 and 2002, from $7.8 million in 2000.
But several vendors breathed new life into behavioral synthesis this year, including Celoxica, Forte Design, Mentor and Synfora. "There's always been some concern and suspicion about how good behavioral synthesis is," said Tedd Hadley, Y Explorations' CEO. "Our results are good, but obviously some designs will get better results than others."
Most Excite customers are in Japan, Hadley said. Among them is semiconductor manufacturer Renesas Technology Corp. "We're doing OK on sales we're not taking investment money at this point," he said. "Our next phase is to continue product development." Hadley acknowledged that competing with much larger EDA vendors will be a challenge. "This is the first year we've seen some serious competition," he said.
Excite has some unique strengths, Hadley said. One is simply the long background of the technology, which spans some 15 years of research at UC Irvine. Another is its use of untimed ANSI C. Mentor Graphics Corp.'s Catapult uses untimed C++, while Forte Design Systems' Cynthesizer and Celoxica Ltd.'s Agility use SystemC. Untimed C is the most common type of legacy code that's out there, Hadley said. But this raises the question of how to represent hardware concepts such as concurrency. In response, Y Explorations is developing Excite Expert, which provides extensions to ANSI C that allow cycle-accurate specifications, parallelism, communication, exception handling and architectural constraints.
Another distinction, Hadley said, is what the company calls "reuse automation." He explained that Excite has a database that lends itself well to designs with intellectual-property blocks. "You can have a black box, and all you need to do is write an interface," he said.
Indeed, Excite includes C optimization, architectural exploration, interface synthesis and behavioral synthesis. The output is synthesizable VHDL or Verilog, along with a testbench. Hadley said the tool offers automated synthesis, but also allows users to interactively explore architectures and use pragmas to instruct the tool.
As for quality of results compared with handcrafted RTL code, Hadley said, "Sometimes we can exceed it, sometimes we're as good as it, sometimes we're not as good. But in every case we're much, much faster."
The new 3.0 release adds a hierarchical synthesis capability to Excite. It can take function calls and, instead of automatically in-lining every one, turn them into separate processes, Hadley said. This reduces synthesis time and verification complexity, he said. "You can build up a database of these functions and the tool will reuse them during synthesis." Also new is a design quality analysis that reports expected clock periods and areas.
One announced customer for Excite 3.0 is Mitsubishi Corp.'s Advanced Technology R&D Center. The new version is available now starting at around $80,000.