OpenPOWER Microwatt
| General information | |
|---|---|
| Launched | 2019-08-29[1] |
| Designed by | IBM, OpenPOWER Foundation |
| Physical specifications | |
| Cores |
|
| Architecture and classification | |
| Application | Soft core |
| Instruction set | Power ISA 3.0 ppc64le ppc64be |
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
[edit]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
[edit]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
[edit]- 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
[edit]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
[edit]References
[edit]- ↑ Williams, Chris (2019-08-29). "Get your royalty-free soft-core OpenPOWER processor core blueprints here. Extra, extra – read all about it". The Register.
- 1 2 "OpenPOWER Summit NA 2019: Day 2 Keynote Demonstration: Anton Blanchard, IBM & Joe DeLaere, Xilinx". September 16, 2019 – via YouTube.
- 1 2 3 ""POWER OpenISA and Microwatt introduction" - Anton Blanchard (LCA 2020)". January 17, 2020 – via YouTube.
- 1 2 3 4 ""Microwatt Microarchitecture" - Paul Mackerras (LCA 2020)". January 13, 2020 – via YouTube.
- ↑ "Microwatt and the POWER ISA support in Renode – Zephyr Project".
- ↑ "Linux on Microwatt". asciinema.org. May 19, 2020.
- ↑ Edge, Jake (August 21, 2019). "OpenPOWER opens further" – via LWN.net.
- ↑ "Day 2 keynote and OpenPOWER blows the doors off: royalty-free, open soft-core (RISC-V sweating gallons)". August 20, 2019.
- ↑ "Microwatt floats". September 3, 2020.
- ↑ "antonblanchard/chiselwatt". May 22, 2026 – via GitHub.
- ↑ "OpenPOWER Foundation". OpenPOWER Foundation.
- ↑ "libre-soc". libre-soc.org.
- ↑ "Raptor Announces Kestrel Open-Source, Open HDL/Firmware Soft BMC".
- ↑ "README.md · master · Kestrel Collaboration / Kestrel LiteX / litex-boards". GitLab. April 28, 2025.
- ↑ Morgan, Timothy Prickett (August 20, 2019). "Big Blue Open Sources Power Chip Instruction Set".
- ↑ "Open MPW metadata for Microwatt". Archived from the original on 2021-02-28. Retrieved 2021-03-30.
- ↑ "Efabless". Efabless. Retrieved 2024-02-16.