Engineering:OpenPOWER Microwatt
| General Info | |
|---|---|
| Launched | 2019-08-29[1] |
| Designed by | IBM, OpenPOWER Foundation |
| Architecture and classification | |
| Application | Soft core |
| Instruction set | Power ISA 3.0 ppc64le ppc64be |
| Physical specifications | |
| Cores |
|
| History | |
Microwatt is an open source soft processor core originally written in VHDL by Anton Blanchard at IBM, announced at the OpenPOWER Summit NA 2019[2] and published on GitHub in August 2019. It adheres to the Power ISA 3.0 instruction set and can be run on FPGA boards, booting Linux, MicroPython and Zephyr.[3][4][5][6][7][8]
Design
Microwatt is a tiny 64-bit bi-endian scalar integer processor core, implementing a subset of the Power ISA 3.0 instruction set. It has 32× 64-bit general purpose registers and 32x 64-bit floating-point registers. It uses Wishbone for the memory interface.[4]
The initial development was done in a couple of months, included the entire integer processing functionality of the instruction set; the bare minimum to make it compliant, with no memory management unit (MMU) and no floating-point unit.[4]
Later additions to the implementation includes JTAG debugger interface, divider instructions, 16 KB instruction and 32 KB data caches, a non-hypervisor-capable MMU, pipelining[4] and floating-point support.[9]
It's designed using VHDL 2008 and the GHDL simulation environment.[3]
Chiselwatt
A sibling project called Chiselwatt is another open processor core implementing the Power ISA 3.0 instruction set, written in the Scala-based Chisel instead of VHDL.[10][11]
Implementations
- Microwatt itself
- Libre-SOC – A libre system on a chip under development that uses Microwatt as a reference design.[12]
- Kestrel – A soft BMC in Raptor Engineering POWER9 based workstations.[13][14]
History
It is the first processor written from scratch using the open Power ISA 3.0, and is released by the OpenPOWER Foundation as a reference design.
The project started as a demo, proof of concept and a reference implementation for the release of the opensource initiative regarding Power ISA 3.0.[15] The goal for Blanchard was to see if he could make it, and as a software developer, taking on a very low level hardware project was a challenge.[2][3]
Microwatt is set to be fabricated in 130 nm by Efabless "Open MPW Shuttle Program" in 2021.[16] As of February 2024, there has been no update on the progress of fabrication on Efabless's Microwatt project page.[17]
See also
References
- ↑ Williams, Chris (2019-08-29). "Get your royalty-free soft-core OpenPOWER processor core blueprints here. Extra, extra – read all about it" (in en). The Register. https://www.theregister.com/2019/08/29/intel_10nm_fpga_openpower/.
- ↑ 2.0 2.1 "OpenPOWER Summit NA 2019: Day 2 Keynote Demonstration: Anton Blanchard, IBM & Joe DeLaere, Xilinx". September 16, 2019. https://www.youtube.com/watch?v=JdMTLs7EMM0.
- ↑ 3.0 3.1 3.2 ""POWER OpenISA and Microwatt introduction" - Anton Blanchard (LCA 2020)". January 17, 2020. https://www.youtube.com/watch?v=RU6RPYAqFzE.
- ↑ 4.0 4.1 4.2 4.3 ""Microwatt Microarchitecture" - Paul Mackerras (LCA 2020)". January 13, 2020. https://www.youtube.com/watch?v=JkDx_y0onSk.
- ↑ "Microwatt and the POWER ISA support in Renode – Zephyr Project". https://www.zephyrproject.org/microwatt-and-the-power-isa-support-in-renode/.
- ↑ "Linux on Microwatt". May 19, 2020. https://asciinema.org/a/331758.
- ↑ Edge, Jake (August 21, 2019). "OpenPOWER opens further". https://lwn.net/Articles/796796/.
- ↑ "Day 2 keynote and OpenPOWER blows the doors off: royalty-free, open soft-core (RISC-V sweating gallons)". August 20, 2019. https://www.talospace.com/2019/08/day-2-keynote-and-openpower-blows-doors.html.
- ↑ "Microwatt floats". September 3, 2020. https://www.talospace.com/2020/09/microwatt-floats.html.
- ↑ "antonblanchard/chiselwatt". May 22, 2026. https://github.com/antonblanchard/chiselwatt.
- ↑ "OpenPOWER Foundation". https://openpowerfoundation.org/blog/final-draft-of-the-power-isa-eula-released/.
- ↑ "libre-soc". https://libre-soc.org/?PageSpeed=noscript.
- ↑ "Raptor Announces Kestrel Open-Source, Open HDL/Firmware Soft BMC". https://www.phoronix.com/scan.php?page=news_item&px=Raptor-Kestrel.
- ↑ "README.md · master · Kestrel Collaboration / Kestrel LiteX / litex-boards". April 28, 2025. http://gitlab.raptorengineering.com/kestrel-collaboration/kestrel-litex/litex-boards/-/blob/master/README.md.
- ↑ Morgan, Timothy Prickett (August 20, 2019). "Big Blue Open Sources Power Chip Instruction Set". https://www.nextplatform.com/2019/08/20/big-blue-open-sources-power-chip-instruction-set/.
- ↑ "Open MPW metadata for Microwatt". https://efabless.com/requests/77/project_metadata.
- ↑ "Efabless" (in en). https://platform.efabless.com/projects/1165.
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