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(Image courtesy of Fritzchens Fritz, Flickr).

What Opening the MIPS Architecture Could Mean

RISC-V, the open source chip architecture, is gaining more and more popularity in the semiconductor industry. The membership of the RISC-V Foundation doubled over the last year to more than 200 technology firms, including Google and Qualcomm. It partnered with the Linux Foundation to promote the open design, which anyone can access for free. More than a thousand people attended the first RISC-V Summit last year.

By the end of the first quarter, however, chip designers will have another open source design to choose from. Wave Computing, the latest owner of the MIPS architecture, said it would allow other companies to access the specification without paying licensing or royalty fees. The move could end up barbering the cost of using rival designs from Arm Holdings to build custom chips for artificial intelligence and the Internet of Things. 

Opening MIPS is the latest attempt to increase the usage for the instruction set architecture (ISA), which has long struggled amid unstable ownership. The MIPS architecture has flagged behind Arm, which has shipped inside more than 100 billion devices, including just about every smartphone and tablet. Softbank-owned Arm is increasingly trying to targeting new technologies, like the Internet of Things.

While the smartphone boom bypassed the MIPS architecture, almost 10 billion chips based on it have shipped into thousands of electronics devices. The MIPS architecture plays a major role in the embedded processor market and hundreds of customers continue to use it commercially, including Microchip Technology, Mobileye and MediaTek. Common applications are set-top boxes, residential gateways and routers.

"Having spent years in the open source technology movement, I can attest to the hunger for community-driven solutions," Art Swift, president of the MIPS licensing business at Wave Computing, said in a statement. The company hired Swift last month from Esperanto Technologies, which is building chips for data centers using RISC-V. He has also served as vice chair of marketing for the nonprofit RISC-V Foundation.

By opening the MIPS architecture, the company is trying to tap into the emerging demand for RISC-V technology, which poses a threat to ARM-based chips. SiFive, a startup founded by the researchers that developed RISC-V, has raised $64 million to build RISC-V chips and license them to other companies targeting the Internet of Things and data centers. Major chip companies have started using custom RISC-V cores to handle housekeeping jobs in chips.

"However, until now, there has been a lack of open source access to industry-standard, patent-protected and silicon-proven architectures," according to Swift, who also serves as president of the open source Prpl Foundation. “When we open the MIPS architecture we are talking about everything companies could have had to pay millions of dollars to access before,” he told Electronic Design.

"Everything has shipped in silicon," Swift said. "And the software infrastructure exists."

Under the MIPS Open program announced last month, users will be granted access to both the 32-bit and 64-bit versions of the MIPS architecture, lowering the bar to build chips around it. Simply sign up and download the base architecture. Users will also be covered by hundreds of MIPS patents. MIPS Open will also ensure that development tools, applications and other services are capable of supporting all MIPS-based cores.

Why would companies consider using the open source MIPS architecture? Look at RISC-V. Many companies say that there is less overhead to designing chips using RISC-V technology. Trimming costs could level the playing field in the semiconductor industry, which has consolidated in an attempt to cope with rising costs. The use of the RISC-V architecture could also open the door to more affordable chip design.

Many companies are also shifting to RISC-V to combat the limits of Moore's Law, the semiconductor industry's blueprint for building faster, smaller and cheaper chips. Each generation of chip manufacturing is taking longer to develop than the last, leading many technology companies looking to edge out the competition in artificial intelligence or other areas to focus increasingly on custom chips instead of off-the-shelf silicon.

Since the RISC-V architecture is open, companies can add functions on top of the base architecture, lowering the bar for application-specific processors. Many companies that pay for access to Arm Cortex technology—ranging from Qualcomm to Amazon—similarly have the ability to graft so-called extensions onto the base architecture. But they are much more limited in what they can and cannot change.

Wave, which is based in Silicon Valley and was founded in 2008, is also trying to boost the flexibility of the MIPS architecture. The MIPS Open program will give users access to single instruction, multiple data (SIMD) and digital signal processing (DSP) functions. The program will also give them access to MIPS multithreading, a technique that allows a processor to execute several commands at once.

"MIPS is not that late to the game," said IHS Markit embedded processor analyst Thomas Hackenberg, adding that RISC-V processors today are not shipping in any significant volumes. "Both MIPS and RISC-V belong to an emerging class of open source core architecture. They both bring unique capabilities to the table and could carve out separate market niches for themselves." He added: "They could both be very successful."

The MIPS architecture, which was introduced in 1985, is based on the reduced instruction set computer—also referred to as RISC—developed at the University of California, Berkeley, in 1980. The ARM architecture, which was released the same year as MIPS, also uses RISC technology. RISC-V, which is not owned by any one company and was introduced in 2010, is the fifth generation of RISC.

MIPS Technologies, which started licensing the MIPS architecture in 1984, was never able to dent the smartphone space dominated by Arm. The company started losing influence in the semiconductor industry as a result of Arm-based chips becoming entrenched in Google's Android and Apple's iOS operating systems. Shipments of chips based on Arm technology soared, while the MIPS architecture was left in the dust.

The Silicon Valley company was still losing momentum when Imagination Technologies, another licensing firm, acquired it in 2013. The company was trying to steal market share from Arm's Cortex technology, which is used in the vast majority of smartphones and tablets. The plan was to offer phone manufacturers a combination of MIPS processor cores and Imagination's PowerVR graphics processors. But the strategy flopped.

Last year, after Imagination announced that it was losing its largest graphics customer by revenue, the company starting shopping the MIPS architecture. It was offloaded to Tallwood Venture Capital, an investment firm founded by Data Banatao. MIPS Technologies briefly returned to Silicon Valley before it was sold to Wave, which is also building custom chips for training artificial intelligence in data centers and edge servers.

Wave is headed by many former executives from the first incarnation of MIPS Technologies. They are pushing the MIPS architecture for artificial intelligence applications in cars, factories and Internet of Things devices installed close to where information is collected. "These applications could lend themselves to an emerging architecture," said Hackenberg. "Maybe that could be an open source MIPS core," he added.

Opening the MIPS architecture could also end up bolstering the company's licensing business. More companies running applications and other software on MIPS-based chips could give it more potential customers. "The MIPS-based solutions developed under MIPS Open will complement our existing and future MIPS IP cores that Wave will continue to create and license globally," said Chief Business Officer Lee Flanagin in a statement.

The main question is whether opening the MIPS architecture is enough to change anyone’s mind about it. Chip designers have had an open source architecture in RISC-V for almost a decade. Do they need another one? "RISC-V has been gaining interest and its adoption caters to some of the organic demand for an open architecture," said Chris Rommel, executive vice president of market researcher VDC Research.

"It is unclear to me if MIPS can gain a sufficient following in the ecosystem as an open source entity," added Rommel. 

Despite playing down the threat of open architectures, Arm is starting to get the message. The company has started giving customers broader access to chip designs without licensing fees. Last year, it moved to end licensing fees for lower-end Cortex-M0 and Cortex-M1 microcontrollers. Companies only have to pay royalties if the product is successful. The company also lowered the cost of its Cortex-A5 core.

"MIPS long ago established a stronghold, but Arm's growth over the past decade is evidence of its technical and market appeal," Rommel told Electronic Design. "RISC-V simply provided a needed third option that offers innovation and business model flexibility." The MIPS Open program, he said, "has to build a developer ecosystem to jump start interest since many semiconductor companies—and startups—seem to be focusing on RISC-V."

On the other hand, the MIPS architecture already has thousands of developers. "They are probably saying, 'We cannot allow ourselves to be squeezed between an open architecture and the Arm ecosystem,'" said Hackenberg. "That allows them to come in and say, 'If you're looking for an open source architecture, you don't have to develop a software ecosystem. We have the ecosystem in place.’ They can hit the ground running.”

Swift, who was vice president of marketing and business development for MIPS Technologies from 2009 to 2011, said that the MIPS architecture today is on pace to ship inside a billion chips per year. The technology is used by hundreds of customers. And they have access to development tools, applications, features and other services that companies using the RISC-V architecture have had to build from the ground up.  

"All our investment is going to pay off with MIPS Open," Swift said. "We are definitely not starting from scratch.”

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