OpenPower Microwatt
The Microwatt is an open source soft processor core originally written 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]
General information | |
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Launched | 2019-08-29[1] |
Designed by | IBM, OpenPOWER Foundation |
Architecture and classification | |
Application | Soft core |
Instruction set | Power ISA 3.0 ppc64le |
Physical specifications | |
Cores |
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Implementation
The Microwatt is a tiny 64-bit little endian scalar integer processor core, implementing a subset of the Power ISA 3.0 instruction set. It has 64× 64-bit general purpose 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 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, pipelining[4] and floating-point support.[9]
It's designed using VHDL 2008 and the GHDL simulation environment.[3]
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.[12] 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]
References
- Williams, Chris (2019-08-29). "Get your royalty-free soft-core OpenPOWER processor core blueprints here. Extra, extra – read all about it". The Register.
- OpenPOWER Summit NA 2019: Day 2 Keynote Demonstration: Anton Blanchard, IBM & Joe DeLaere, Xilinx
- "POWER OpenISA and Microwatt introduction" - Anton Blanchard (LCA 2020)
- "Microwatt Microarchitecture" - Paul Mackerras (LCA 2020)
- Microwatt and the POWER ISA support in Renode
- Linux on Microwatt
- OpenPOWER opens further
- Day 2 keynote and OpenPOWER blows the doors off: Royalty-free, open soft-core (RISC-V sweating gallons)
- Microwatt Floats
- Chiselwatt's page on Github
- Final Draft of the Power ISA EULA Released
- Big Blue open sources POWER chip instruction set