OpenPOWER Microwatt#Chiselwatt
{{Short description|Open source processor core}}
{{Infobox CPU
| name = Microwatt
| image =
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| produced-start = 2019-08-29{{cite web
| last1 = Williams
| first1 = Chris
| title = Get your royalty-free soft-core OpenPOWER processor core blueprints here. Extra, extra – read all about it
| url = https://www.theregister.com/2019/08/29/intel_10nm_fpga_openpower/
| work = The Register
| language = en
| date = 2019-08-29}}
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| designfirm = IBM, OpenPOWER Foundation
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| arch = Power ISA 3.0
ppc64le
ppc64be
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| application = Soft core
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Microwatt is an open source soft processor core originally written in VHDL by Anton Blanchard at IBM, announced at the OpenPOWER Summit NA 2019[https://www.youtube.com/watch?v=JdMTLs7EMM0 OpenPOWER Summit NA 2019: Day 2 Keynote Demonstration: Anton Blanchard, IBM & Joe DeLaere, Xilinx] 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.[https://www.youtube.com/watch?v=RU6RPYAqFzE "POWER OpenISA and Microwatt introduction" - Anton Blanchard (LCA 2020)][https://www.youtube.com/watch?v=JkDx_y0onSk "Microwatt Microarchitecture" - Paul Mackerras (LCA 2020)][https://www.zephyrproject.org/microwatt-and-the-power-isa-support-in-renode/ Microwatt and the POWER ISA support in Renode][https://asciinema.org/a/331758 Linux on Microwatt][https://lwn.net/Articles/796796/ OpenPOWER opens further][https://www.talospace.com/2019/08/day-2-keynote-and-openpower-blows-doors.html Day 2 keynote and OpenPOWER blows the doors off: Royalty-free, open soft-core (RISC-V sweating gallons)]
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.
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.
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 and floating-point support.[https://www.talospace.com/2020/09/microwatt-floats.html Microwatt Floats]
It's designed using VHDL 2008 and the GHDL simulation environment.
= 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.[https://github.com/antonblanchard/chiselwatt Chiselwatt's page on Github][https://openpowerfoundation.org/final-draft-of-the-power-isa-eula-released/ Final Draft of the Power ISA EULA Released]
Implementations
- Microwatt itself
- Libre-SOC – A libre system on a chip under development that uses Microwatt as a reference design.[https://libre-soc.org Libre-SOC]
- Kestrel – A soft BMC in Raptor Engineering POWER9 based workstations.{{cite web | url=https://www.phoronix.com/scan.php?page=news_item&px=Raptor-Kestrel | title=Raptor Announces Kestrel Open-Source, Open HDL/Firmware Soft BMC }}[https://gitlab.raptorengineering.com/kestrel-collaboration/kestrel-litex/litex-boards/-/blob/master/README.md Kestrel SoftBMC Project]
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.[https://www.nextplatform.com/2019/08/20/big-blue-open-sources-power-chip-instruction-set/ Big Blue open sources POWER chip instruction set] 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.
Microwatt is set to be fabricated in 130 nm by Efabless "Open MPW Shuttle Program" in 2021.{{Cite web |url=https://efabless.com/requests/77/project_metadata |title=Open MPW metadata for Microwatt |access-date=2021-03-30 |archive-date=2021-02-28 |archive-url=https://web.archive.org/web/20210228091345/https://efabless.com/requests/77/project_metadata |url-status=dead }} As of February 2024, there has been no update on the progress of fabrication on Efabless's Microwatt project page.{{Cite web |title=Efabless |url=https://platform.efabless.com/projects/1165 |access-date=2024-02-16 |website=Efabless |language=en}}
See also
References
{{Reflist}}
External links
- {{github|antonblanchard/microwatt}}
{{Programmable Logic}}
{{Soft microprocessors}}