Resources and Specifications

This page aims to collect all the resources and specifications we need in one place for quick access. We will try our best to keep links here up-to-date. Feel free to add more links here.

Getting Started

This section is primarily a series of useful links found online

Is Open Source Hardware Profitable?

RaptorCS on FOSS Hardware Interview

OpenPOWER ISA

Overview of the user ISA:

Raymond Chen's PowerPC series

OpenPOWER OpenFSI Spec (2016)

Communities

JTAG

Radix MMU

D-Cache

D-Cache Possible Optimizations papers and links

BW Enhancing Shared L1 Cache Design research done in cooperation with AMD

RTL Arithmetic SQRT, FPU etc.

Wallace vs Dadda Multipliers

Sqrt

CORDIC and related algorithms

IEEE Standard for Floating-Point Arithmetic (IEEE 754)

Almost all modern computers follow the IEEE Floating-Point Standard. Of course, we will follow it as well for interoperability.

Note: Even though this is such an important standard used by everyone, it is unfortunately not freely available and requires a payment to access. However, each of the Libre-SOC members already have access to the document.

Among other things, has a nice explanation on arithmetic, rounding modes and the sticky bit.

Nice resource on rounding errors (ulps and epsilon) and the "table maker's dilemma".

Past FPU Mistakes to learn from

Khronos Standards

The Khronos Group creates open standards for authoring and acceleration of graphics, media, and computation. It is a requirement for our hybrid CPU/GPU to be compliant with these standards as well as with IEEE754, in order to be commercially-competitive in both areas: especially Vulkan and OpenCL being the most important. SPIR-V is also important for the Kazan driver.

Thus the zfpacc proposal has been created which permits runtime dynamic switching between different accuracy levels, in userspace applications.

SPIR-V Main Page Link

Vulkan Main Page Link

OpenCL Main Page

Note: We are implementing hardware accelerated Vulkan and OpenCL while relying on other software projects to translate APIs to Vulkan. E.g. Zink allows for OpenGL-to-Vulkan in software.

Open Source (CC BY + MIT) DirectX specs (by Microsoft, but not official specs)

https://github.com/Microsoft/DirectX-Specs

Graphics and Compute API Stack

I found this informative post that mentions Kazan and a whole bunch of other stuff. It looks like many APIs can be emulated on top of Vulkan, although performance is not evaluated.

https://synappsis.wordpress.com/2017/06/03/opengl-over-vulkan-dev/

3D Graphics Texture compression software and hardware

Various POWER Communities

  • An effort to make a 100% Libre POWER Laptop The T2080 is a POWER8 chip.
  • Power Progress Community Supporting/Raising awareness of various POWER related open projects on the FOSS community
  • OpenPOWER Promotes and ensure compliance with the Power ISA amongst members.
  • OpenCapi High performance interconnect for POWER machines. One of the big advantages of the POWER architecture. Notably more performant than PCIE Gen4, and is designed to be layered on top of the physical PCIE link.
  • OpenPOWER “Virtual Coffee” Calls Truly open bi-weekly teleconference lines for anybody interested in helping advance or adopting the POWER architecture.

Conferences

see conferences

Coriolis2

Note: The rest of LIP6's website is in French, but there is a UK flag in the corner that gives the English version.

Klayout

image to GDS-II

  • https://nazca-design.org/convert-image-to-gds/

The OpenROAD Project

OpenROAD seeks to develop and foster an autonomous, 24-hour, open-source layout generation flow (RTL-to-GDS).

Other RISC-V GPU attempts

TODO: Get in touch and discuss collaboration

Tests, Benchmarks, Conformance, Compliance, Verification, etc.

RISC-V Tests

RISC-V Foundation is in the process of creating an official conformance test. It's still in development as far as I can tell.

  • //TODO LINK TO RISC-V CONFORMANCE TEST

IEEE 754 Testing/Emulation

IEEE 754 has no official tests for floating-point but there are well-known third party tools to check such as John Hauser's TestFloat.

There is also his SoftFloat library, which is a software emulation library for IEEE 754.

Jacob is also working on an IEEE 754 software emulation library written in Rust which also has Python bindings:

A cool paper I came across in my research is "IeeeCC754++ : An Advanced Set of Tools to Check IEEE 754-2008 Conformity" by Dr. Matthias Hüsken.

Khronos Tests

OpenCL Conformance Tests

Vulkan Conformance Tests

MAJOR NOTE: We are not allowed to say we are compliant with any of the Khronos standards until we actually make an official submission, do the paperwork, and pay the relevant fees.

Formal Verification

Formal verification of Libre RISC-V ensures that it is bug-free in regards to what we specify. Of course, it is important to do the formal verification as a final step in the development process before we produce thousands or millions of silicon.

Some learning resources I found in the community:

Automation

LLVM

Adding new instructions:

Branch Prediction

Python RTL Tools

Other

Real/Physical Projects

ASIC tape-out pricing

Funding

Good Programming/Design Practices

12 skills summary

Analog Simulation

Libre-SOC Standards

This list auto-generated from a page tag "standards":

register type tags
Posted Wed Jun 30 20:54:14 2021
int fp mv
Posted Sat May 29 09:34:48 2021
16 bit compressed
Posted Mon May 10 21:37:20 2021
av opcodes
Posted Mon May 10 21:37:20 2021
bitmanip
Posted Mon May 10 21:37:20 2021
byteswap
Posted Mon May 10 21:37:20 2021
cr int predication
Posted Mon May 10 21:37:20 2021
fcvt
Posted Mon May 10 21:37:20 2021
ldst
Posted Mon May 10 21:37:20 2021
mv.swizzle
Posted Mon May 10 21:37:20 2021
mv.vec
Posted Mon May 10 21:37:20 2021
mv.x
Posted Mon May 10 21:37:20 2021
propagation
Posted Mon May 10 21:37:20 2021
remap
Posted Mon May 10 21:37:20 2021
setvl
Posted Mon May 10 21:37:20 2021
sprs
Posted Mon May 10 21:37:20 2021
sv
Posted Mon May 10 21:37:20 2021
svp64
Posted Mon May 10 21:37:20 2021
vector ops
Posted Mon May 10 21:37:20 2021
vector swizzle
Posted Mon May 10 21:37:20 2021
remap
Posted Tue Jun 25 14:21:45 2019

Server setup

Testbeds

Really Useful Stuff

Digilent Arty

  • https://store.digilentinc.com/pmod-sf3-32-mb-serial-nor-flash/
  • https://store.digilentinc.com/arty-a7-artix-7-fpga-development-board-for-makers-and-hobbyists/
  • https://store.digilentinc.com/pmod-vga-video-graphics-array/
  • https://store.digilentinc.com/pmod-microsd-microsd-card-slot/
  • https://store.digilentinc.com/pmod-rtcc-real-time-clock-calendar/
  • https://store.digilentinc.com/pmod-i2s2-stereo-audio-input-and-output/

CircuitJS experiments

Logic Simulator 2

Features

  1. Micro-subset verilog-like DSL for coding the array of logic gates (parsed using Antlr)
  2. Monaco-based code editor with automatic linting/error reporting, smart indentation, code folding, hints
  3. IDE docking ui courtesy of JupyterLab's Lumino widgets
  4. Schematic visualisation courtesy of d3-hwschematic
  5. Testbench simulation with graphical trace output and schematic animation
  6. Circuit description as gates, boolean logic or verilog behavioural model
  7. Generate arbitrary outputs from truth table and Sum of Products or Karnaugh Map

[from the GitHub page. As of 2021/03/29]

ASIC Timing and Design flow resources

Geometric Haskell Library

TODO investigate

     https://github.com/idea-fasoc/OpenFASOC
     https://www.quicklogic.com/2020/06/18/the-tipping-point/
     https://www.quicklogic.com/blog/
     https://www.quicklogic.com/2020/09/15/why-open-source-ecosystems-make-good-business-sense/
     https://www.quicklogic.com/qorc/
     https://en.wikipedia.org/wiki/RAD750
     The RAD750 system has a price that is comparable to the RAD6000, the latter of which as of 2002 was listed at US$200,000 (equivalent to $284,292 in 2019).
     https://theamphour.com/525-open-fpga-toolchains-and-machine-learning-with-brian-faith-of-quicklogic/
     https://github.blog/2021-03-22-open-innovation-winning-strategy-digital-sovereignty-human-progress/
     https://github.com/olofk/edalize
     https://github.com/hdl/containers
     https://twitter.com/OlofKindgren/status/1374848733746192394
     You might also want to check out https://umarcor.github.io/osvb/index.html
     https://www.linkedin.com/pulse/1932021-python-now-replaces-tcl-all-besteda-apis-avidan-efody/
     “TCL has served us well, over the years, allowing us to provide an API, and at the same time ensure nobody will ever use it. I will miss it”.
     https://sphinxcontrib-hdl-diagrams.readthedocs.io/en/latest/examples/comb-full-adder.html
     https://sphinxcontrib-hdl-diagrams.readthedocs.io/en/latest/examples/carry4.html
     FuseSoC is used by MicroWatt and Western Digital cores
     OpenTitan also uses FuseSoC
     LowRISC is UK based
     https://antmicro.com/blog/2020/12/ibex-support-in-verilator-yosys-via-uhdm-surelog/