Power ISA

3 Articles

Open Hardware Laptop Built On Power PC ISA

August 28, 2020 by 17 Comments

Since Apple switched to Intel chips in the mid-00s, the PowerPC chips from Motorola and the PowerPC Instruction Set Architecture (ISA) that they had been using largely fell by the wayside. While true that niche applications like supercomputing still use the Power ISA on other non-Apple hardware, the days of personal computing with PowerPC are largely gone unless you’re still desperately trying to keep your Power Mac G5 out of the landfill or replaying Twilight Princess. Luckily for enthusiasts, though, the Power ISA is now open source and this group has been working on an open-source laptop based on this architecture.

While development is ongoing and there are no end-user products available yet, the progress that this group has made shows promise. They have completed their PCB designs and schematics and have a working bill of materials, including a chassis from Slimbook. There are also prototypes with a T2080RDB development kit and a NXP T2080 processor, although they aren’t running on their intended hardware yet. While still in the infancy, there are promising videos (linked below) which show the prototypes operating smoothly under the auspices of the Debian distribution that is tailored specifically for the Power ISA.

We are excited to see work continue on this project, as the Power ISA has a number of advantages over x86 in performance, ARM when considering that it’s non-proprietary, and even RISC-V since it is older and better understood. If you want a deeper comparison between all of these ISAs, our own [Maya Posch] covered that topic in detail as well as covered the original move that IBM made to open-source the Power ISA.

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IBM Reveals POWER10 CPU Based On The OpenPOWER ISA 3.1 Specification

August 19, 2020 by 22 Comments

This week, IBM revealed their POWER10 CPU, which may not seem too exciting since it’s primarily aimed at big iron like mainframes and servers. The real news for most is that it is the first processor to be released that is based on the open Power ISA specification v3.1. This new version of the Power ISA adds a number of new instructions as well as the notion of optionality. It updates the v3.0 specification that was released in 2015, right after the founding of the OpenPOWER Foundation.

Currently, a number of open source designs for the Power ISA exists, including MicroWatt (Power v3.0, VHDL) and the similar ChiselWatt (written in Scala-based Chisel).  In June of this year, IBM also released the VHDL code for the IBM A2 processor on Github. This is a multi-core capable, 4-way multithreaded 64-bit design, with silicon-implementations running at up to 2.3 GHz and using the Power ISA v2.06 specification.

The ISA specifications and other relevant technical documentation can be obtained from the OpenPOWER website, such as for example the Power ISA v3.0B specification from 2017. The website also lists the current cores and communities around the Power ISA.

(Main image: POWER10 CPU, credit IBM)

Joining The RISC-V Ranks: IBM’s Power ISA To Become Free

August 23, 2019 by 38 Comments

IBM’s Power processor architecture is probably best known today as those humongous chips that power everything from massive mainframes and supercomputers to slightly less massive mainframes and servers. Originally developed in the 1980s, Power CPUs have been a reliable presence in the market for decades, forming the backbone of systems like IBM’s RS/6000 and AS/400 and later line of Power series.

Now IBM is making the Power ISA free to use after first opening up access to the ISA with the OpenPower Foundation. Amidst the fully free and open RISC-V ISA making headway into the computing market, and ARM feeling pressured to loosen up its licensing, it seems they figured that it’s best to join the party early. Without much of a threat to its existing business customers who are unlikely to whip up their own Power CPUs in a back office and not get IBM’s support that’s part of the business deal, it seems mostly aimed at increasing Power’s and with it IBM’s foothold in the overall market.

The Power ISA started out as the POWER ISA, before it evolved into the PowerPC ISA, co-developed with Motorola  and Apple and made famous by Apple’s use of the G3 through G5 series of PowerPC CPUs. The PowerPC ISA eventually got turned into today’s Power ISA. As a result it shares many commonalities with both POWER and PowerPC, being its de facto successor.

In addition, IBM is also opening its OpenCAPI accelerator and OpenCAPI Memory Interface variant that will be part of the upcoming Power9′ CPU. These technologies are aimed at reducing the number of interconnections required to link CPUs together, ranging from NVLink, to Infinity Fabric and countless more, not to mention memory, where OMI memory could offer interesting possibilities.

Would you use Power in your projects? Let us know in the comments.