MIPS Open R6 Architecture Now Available

Article By : Junko Yoshida

MIPS 32-bit and 64-bit architecture – the most recent version, release 6 – became available Thursday (March 28) for anyone to download at MIPS Open web page.

Under the MIPS Open program, participants have full access to the MIPS R6 architecture free of charge – with no licensing or royalty fees.

“We are keeping our original promise on schedule,” Art Swift, president of its MIPS licensing business, told us. Late last year, Wave Computing, which owns MIPS, promised to make MIPS available for open use by the end of the first quarter of 2019.

Asked if any other MIPS cores – beyond R6 – will be available in the future, Swift said additional announcements are in the offing, indicating that Thursday’s offering is only the first set of MIPS Open’s release.

“Remember, this is a journey, not a destination,” Swift reminded.

Other pending announcements include MIPS Open’s certification partners and MIPS Open Advisory Board. Names of individuals or companies for those initiatives are not yet public.


So, what are the specifics for download at MIPS Open today? Included in this first release are:

  • The open source version of the 32 and 64-bit MIPS Instruction Set Architecture (ISA), Release 6
  • MIPS SIMD Extensions
  • MIPS DSP Extensions
  • MIPS Multi-Threading
  • microMIPS code compression
  • MIPS Virtualization

MIPS Open is also offering its first set of “deliverables.” “Deliverables” are “components” or “elements” of the MIPS Open Program that developers need to design their own MIPS cores using MIPS ISA. These components include MIPS Open Tools and MIPS Open FPGAs.

MIPS Open Tools cover integrated development environment for embedded real-time operating systems and Linux-based systems for embedded products. They will enable developers to build, debug and deploy applications on MIPS-based hardware and software platforms.

MIPS Open FPGAs, on the other hand, is a complete training program for community members. MIPSfpga, according to Swift, was originally developed as a classroom academic program. It comes with a comprehensive set of materials for a MIPS CPU, allowing students to see the actual RTL code and inner workings of the processor. MIPS Open FPGAs “should be helpful to developers who need to familiarize themselves with MIPS architecture,” Swift noted.

One more item available at MIPS Open is RTL code for the MIPS microAptiv core. Swift, however, made it clear that this is a sample code, available just for non-commercial use. The objective is to let developers explore microarchitecture features of MIPS, as microAptive is MIPS’ smallest, lowest-power CPU family.

The actual release of microAptive core, however, is several weeks away, according to Swift.

Is MIPS relevant?

Wave Computer's initial announcement to go open source with MIPS — announced late last year — stunned many, but industry observers saw it as a smart move on the part of Wave. Kevin Krewell, principal analyst at Tirias Research, went a step further and told us, "This is Wave Computer's chance to make a 'diving catch' to keep the MIPS instruction set relevant." He said. "By hiring Art Swift and offering an open MIPS core, Wave is trying to steal some momentum from RISC-V."

Krewell argued, "Frankly, they didn't have much option in order to compete with RISC-V. MIPS had already lost the instruction set IP war with Arm." That said, he added, "There's nothing wrong with the venerable MIPS instruction set and it has been proven from microcontrollers to high performance networking processors."

MIPS Open Advisory Board

So, who exactly will decide the future direction of MIPS? Will there be an independent organization?

The MIPS Open Advisory Board will be responsible. Consisting of MIPS Open member companies, partners, universities and technology luminaries, the Advisory Board will be a direction-setting body to make critical decisions on “roadmaps, additional cores to be made available for open use and architectural directions,” Swift explained.

He made it clear, however, “You don’t need to become members of the committee to use MIPS Open’s deliverables.” He added, “Anyone can use it simply by signing a quick-through license.”

What does such a “quick-through license” entail? MIPS Open licensing agreements involve two conditions.

First, subscribers agree not to fragment MIPS architecture. Swift said, “Of course, MIPS already comes with built-in flexibilities. MIPS architectural licensees have been traditionally allowed to modify configurations, add instructions and add accelerators. But you are not allowed to break compatibility with MIPS architecture spec.”

Second is an agreement to put cores and SoCs that use MIPS through a certification process, explained Swift.

In short, MIPS Open offers “open, free-use license to MIPS R6 architecture. Chip developers can build SoCs based on the open-use license. “You have total freedom and flexibility to use open-license cores and modify MIPS configurations in a number of ways. But this isn’t the wild west. You are asked to maintain compatibility with existing MIPS offerings,” Swift explained.

Potential users of MIPS Open

In a previous interview, Swift said MIPS Open might appeal more to traditional, somewhat conservative companies, who prefer “staying within the rules” in an open-source community. “But ‘that base’ who find MIPS Open appealing might be bigger than we had originally expected,” said Swift.

On one hand, MIPS should attract those who want to leverage architectural license to build their own spec from scratch.

On the other hand, developers in need of faster time-to-market cores may just want to take advantage of MIPS’ R&D legacy and use the latest version of the silicon-proven MIPS architecture, Swift explained.

Krewell noted, "RISC-V still has the 'sexy' factor and has a rapidly growing ecosystem." However, he added, "RISC-V is still developing and maturing, so the choice of instruction sets will depend on your risk tolerance."

AI + MIPS strategy

Wave Computing, which acquired MIPS last year, has talked about its vision of “AI for All.” Wave, a designer of AI accelerators, is said to have big plans to push AI from the data center to the edge. MIPS Open will be an initiative critical to that strategy, according to Derek Meyer, CEO of Wave.

Earlier this week, Wave joined Amazon, Facebook, Google and Samsung to support advanced AI research initiatives at the Berkeley Artificial Intelligence Research (BAIR) Lab.

How exactly Wave envisions two open development initiatives, MIPS Open and the BAIR project, linking together to accelerate AI everywhere remains unknown. It needs to be articulated.

Asked about specifics on the “AI+MIPS” strategy, and how that affects MIPS Open’s roadmap, Swift promised more at a later date.

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