The open-source movement that has driven software innovation is now creating a buzz in the microprocessor realm, thanks to the growing popularity of open-source microprocessor instruction set architecture RISC-V. Although the term “open source” conveys sentiments such as research sharing and community building, leading semiconductor IP provider Arm, which supports 95 percent of smartphone embedded processors, is not a fan.

Synced recently sat down with Rhonda Dirvin, who is Arm’s senior director of Embedded, IoT and Automotive Marketing. Dirvin believes today’s open source hardware landscape is not as simple and straightforward as it may seem: “We’re starting to see some people say free is not free. Because at the end of the day they have to look at what it takes to verify that and what it takes to implement the instruction or architecture. You don’t have the whole ecosystem out there that supports it the way that you do with Arm or some of the other more established vendors.”

So how does verifying open source hardware differ from verifying open source software? Outside director at Mellanox Technologies Thomas J Riordan tells Synced he believes the challenges are actually rather similar. “At the Instruction Set Architecture (ISA) level, a processor and an open source program are both pieces of software (algorithms) that are written in some High Level Language (HLL). In both cases, validation of the processor/program must be done in an exhaustive manner to guarantee a quality result.”

“As far as implementing the instruction set architecture goes, the fact that it is open pretty much guarantees that there will be many implementations of it available from multiple sources. That is of course what Arm fears. The power of the open source model has been well validated. RISC-V is the Linux of Processors. Just like Microsoft would have preferred that Linux and Android never existed, Arm would prefer that RISC-V did not exist,” says Riordan.

The year 2019 may prove a tipping point for Arm. The UK-based company has imposed a series of significant changes on microprocessor IP licensing for its clients — mostly semiconductor companies — with the stated intent of providing better access and more flexible chip design options. Earlier this year Arm introduced Arm Flexible Access — providing access to the company’s extensive technology portfolio at a reduced fee and with no obligation to purchase a full license.

At its annual technology conference Arm TechCon this week in San Jose, Arm CEO Simon Segars announced the addition of Custom Instructions to its IoT-focused Cortex-M processor series, starting with Arm Cortex-M33 CPUs in the first half of 2020. This will enable Arm clients to add custom instructions to their Cortex-M-based IoT CPUs to tailor the chips for specific markets.

“For example, there are some mathematical algorithms that are repetitious. If you’re having a storage piece of silicon maintaining that, it would be really nice to be able to have an instruction. That didn’t fit with what Arm wanted. But now (with custom instructions) our partners will be able to optimize the chip for that market,” says Dirvin.

Many industry practitioners and analysts regard these Arm announcements as a response to increasing challenges from RISC-V. Because of the attractive advantages of RISC-V — freely availability, light weight, and extensibility — it has been garnering widespread industry attention from tech titans like NVIDIA and Qualcomm.

Dirvin stresses Arm would have rolled out its policy changes even without the rise of RISC-V. “The pace of the innovation seems to pick up. With 5G, AI, and autonomous driving, disruptive technologies are happening all at once. I think that’s a good point with all the disruption going on around us that we need to disrupt ourselves.”