A Brief History of the MIPS Architecture

MIPS is one of the most prolific, longest-living industry-standard processor architectures, existing in numerous incarnations over nearly three decades.

MIPS has powered products including game systems from Nintendo and Sony; DVRs from Dish Network, EchoStar and TiVo; set-top boxes from Cisco and Motorola; DTVs from Samsung and LG; routers from Cisco, NetGear and Linksys; automobiles from Toyota, Volvo, Lexus and Cadillac; printers from HP, Brother and Ricoh; digital cameras from Canon, Samsung, FujiFilm, Sony, Kodak, Nikon, Pentax and Olympus; and countless others.

At the heart of MIPS is its RISC (reduced instruction set computing) instruction set, which was an entirely new concept for computer architecture at the time of its inception in the early 1980s.

The basic idea of RISC is that using simple instructions, which enable easier pipelining and larger caches, can dramatically boost performance. The emergence of high-level programming languages and compilers in the early 1980s enhanced this value proposition, making it possible for programmers to compile code into simple instructions that would execute extremely quickly.

Around that time, several other industry trends converged, creating an ideal environment for a disruptive company to bring RISC technology to market. These included the advent of the fabless semiconductor model, introduction of UNIX as an open, portable operating system, and proliferation of VLSI design in research labs, enabling increased experimentation with new ideas and technologies such as RISC. You can read more about these trends in a transcript of a 2011 Computer History Museum panel, MIPS Oral History Panel Session 1: Founding the Company.

In 1981, Dr. John Hennessy at Stanford University led a team of researchers in building a new microprocessor using RISC principles – this was the MIPS project.

Technologists John Moussouris, Edward “Skip” Stritter and others then joined Hennessy in 1984 to commercialize the MIPS project, through the creation of MIPS Computer Systems, a fabless semiconductor company that was the first to produce a commercially available RISC microprocessor.

MIPS’ value proposition was in providing high performance at low cost. In retrospect, the benefits of RISC may sound obvious, but at the time, RISC represented a fundamental philosophical shift. The MIPS team not only had to develop and sell a new product, but they also had to evangelize a new design philosophy.

The company’s first chip design, the R2000, was released in 1985, based on the MIPS I Instruction Set Architecture (ISA), and the next design, the R3000, was released in 1988. It was used primarily in SGI’s workstations, and later in workstations and servers from DEC. Based on its growing traction, in 1989, MIPS Computer Systems went public. The R6000 was then introduced based on the MIPS II ISA. In 1991, MIPS released the world’s first 64-bit microprocessor, the R4000. This design was extremely important to MIPS’ biggest customer, SGI, and as such, SGI bought MIPS in 1992. SGI subsequently incorporated MIPS as a wholly owned subsidiary, MIPS Technologies, Inc. It was during this time that SGI introduced its IRIS Crimson product, the first 64-bit workstation, which was featured in the movie Jurassic Park. More about this on Wikipedia here and here.

Over the next several years, MIPS introduced the R8000, R10000 and other processor variants. With each generation, more functionality was added to the MIPS architecture. During this time, MIPS began licensing its processor designs to other companies. By the late 1990s, the MIPS architecture continued to proliferate, and in 1997, the company shipped a record-breaking 48 million units. Riding on this momentum, SGI spun MIPS out as an IP company, with a business model based on licensing its architecture and microprocessor core designs. MIPS Technologies, Inc. subsequently held an IPO in 1998. You can get more in-depth information on the history of MIPS from Wikipedia here.

Around this time, MIPS introduced the 32-bit MIPS32® ISA and the 64-bit MIPS64® ISA – compatible architectures that leveraged the previous MIPS I, MIPS II, MIPS III, MIPS IV and MIPS V releases. With this move, the privilege resource architecture (PRA) and ISAs were standardized, laying the foundation for future innovation.

Since then, the MIPS architecture has continued to evolve, adding numerous innovations including a 64-bit floating point unit for 32-bit CPUs, multi-threading, DSP support, microcontroller-specific extensions, the microMIPS™ code compression ISA, enhanced virtual addressing (EVA) and much more. With Release 5 of the MIPS architecture, the company is rolling out hardware virtualization and SIMD support.

Of course it’s not all about the elegance or capabilities of the ISA. Today, ecosystem is everything. Over the nearly three decades of its life, a large infrastructure of supporting development tools, operating systems, applications, middleware, device drivers and more have grown around MIPS. Support continues to grow, including initiatives such as Linux, Android, Java, JavaScript, HTML5, WebGL, GNU and LLVM toolchains, apps, games and more.

MIPS licensees have shipped more than 3 billion units since 2000. The ever-evolving MIPS architecture is inside of a large range of products, including the majority of DTVs, set-top boxes and WiFi routers shipping today. With the advent of the open, portable Android OS, MIPS is also now shipping inside of mobile devices. As intelligence is increasingly designed into just about every product from thermostats to high-end consumer products, the embedded microprocessor market is thriving, and the MIPS architecture continues to evolve to meet the needs of new generations of products while maintaining its simple, elegant RISC roots. For more info: www.mips.com.