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| author | Aditya Naik | 2023-06-29 17:49:58 -0700 |
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| committer | Aditya Naik | 2023-06-29 17:49:58 -0700 |
| commit | 8200c0cdf1d471453946d5ae24bc99757b2ef02d (patch) | |
| tree | 6154e6e6e76f1bee2fdca3644b26b7a23950855e /README-3.5.x.md | |
| parent | 8ba5f8d5011df70e817d3011ea4afd6976df243e (diff) | |
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diff --git a/README-3.5.x.md b/README-3.5.x.md new file mode 100644 index 00000000..d1d42b83 --- /dev/null +++ b/README-3.5.x.md @@ -0,0 +1,395 @@ + + +--- +### CCC 2022 +CCC(Chisel Community Conference) is an annual gathering of Chisel community enthusiasts and technical exchange workshop. With the support of the Chisel development community and RISC-V International, this conference will bring together designers and developers with hands-on experience in Chisel from home and abroad to share cutting-edge results and experiences from both the open source community as well as industry. + +The recording of CCC 2022 has been uploaded: +1. [Constellation, a Open-source Chisel NoC Generator for SoCs - Jerry Zhao@UCB BAR](https://www.youtube.com/watch?v=8FGnu0Tq3Qk&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=1) +2. [The formal verification capabilities of chiseltest - Kevin Laeufer@UCB BAR](https://www.youtube.com/watch?v=-BUcTwE_URg&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=2) +3. [Chisel Breakdown 03 - Jack Koenig@SiFive](https://www.youtube.com/watch?v=4vgSrW7Cdkk&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=3) +4. [The Next Generation FIRRTL Compiler is Here! - Prithayan Barua&Hideto Ueno@SiFive](https://www.youtube.com/watch?v=V3h30s31qfk&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=4) +5. [Implementing RISC-V Scalar Cryptography/Bitmanip extensions in Chisel - Hongren Zheng@Tsinghua University+PLCT](https://www.youtube.com/watch?v=hXaZMQPRXo0&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=5) +6. [SCIRT: Bridging the Type System Gap for Circuit Generators - Ruikang Wang@Tsinghua University+PLCT](https://www.youtube.com/watch?v=fPl4eZHh1-M&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=6) +7. [ChiselDB: Mapping Hardware Data Structures to Database Tables for Efficient Data Analysis Jiawei Lin@ICT](https://www.youtube.com/watch?v=Df1l9h351BM&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=7) +8. [From Chisel to Chips in Fully Open-Source - Martin Schoeberl@DTU](https://www.youtube.com/watch?v=FenSOWKBbAw&list=PL02hojk7ZTSek-Zro6Zdj_nDlp6khGssJ&index=8) + +See you next year :) + +--- + +The **Constructing Hardware in a Scala Embedded Language** ([**Chisel**](https://www.chisel-lang.org)) is an open-source hardware description language (HDL) used to describe digital electronics and circuits at the register-transfer level that facilitates **advanced circuit generation and design reuse for both ASIC and FPGA digital logic designs**. + +Chisel adds hardware construction primitives to the [Scala](https://www.scala-lang.org) programming language, providing designers with the power of a modern programming language to write complex, parameterizable circuit generators that produce synthesizable Verilog. +This generator methodology enables the creation of re-usable components and libraries, such as the FIFO queue and arbiters in the [Chisel Standard Library](https://www.chisel-lang.org/api/latest/#chisel3.util.package), raising the level of abstraction in design while retaining fine-grained control. + +For more information on the benefits of Chisel see: ["What benefits does Chisel offer over classic Hardware Description Languages?"](https://stackoverflow.com/questions/53007782/what-benefits-does-chisel-offer-over-classic-hardware-description-languages) + +Chisel is powered by [FIRRTL (Flexible Intermediate Representation for RTL)](https://github.com/chipsalliance/firrtl), a hardware compiler framework that performs optimizations of Chisel-generated circuits and supports custom user-defined circuit transformations. + +* [What does Chisel code look like?](#what-does-chisel-code-look-like) + * [LED blink](#led-blink) + * [FIR Filter](#fir-filter) +* [Getting Started](#getting-started) + * [Bootcamp Interactive Tutorial](#bootcamp-interactive-tutorial) + * [A Textbook on Chisel](#a-textbook-on-chisel) + * [Build Your Own Chisel Projects](#build-your-own-chisel-projects) + * [Guide For New Contributors](#guide-for-new-contributors) + * [Design Verification](#design-verification) +* [Documentation](#documentation) + * [Useful Resources](#useful-resources) + * [Chisel Dev Meeting](#chisel-dev-meeting) + * [Data Types Overview](#data-types-overview) +* [Contributor Documentation](#contributor-documentation) + * [Useful Resources for Contributors](#useful-resources-for-contributors) + * [Compiling and Testing Chisel](#compiling-and-testing-chisel) + * [Running Projects Against Local Chisel](#running-projects-against-local-chisel) + * [Building Chisel with FIRRTL in the same SBT Project](#building-chisel-with-firrtl-in-the-same-sbt-project) + * [Chisel3 Architecture Overview](#chisel3-architecture-overview) + * [Chisel Sub-Projects](#chisel-sub-projects) + * [Which version should I use?](#which-version-should-i-use) + * [Chisel Roadmap](#roadmap) + +--- + +[](https://gitter.im/freechipsproject/chisel3?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) + +[](https://github.com/chipsalliance/chisel3/releases/latest) +[](https://index.scala-lang.org/chipsalliance/chisel3/chisel3) +[](https://oss.sonatype.org/content/repositories/snapshots/edu/berkeley/cs/) +[](https://javadoc.io/doc/edu.berkeley.cs/chisel3_2.13/latest) + +## What does Chisel code look like? + +### LED blink + +```scala +import chisel3._ +import chisel3.util._ + +class Blinky(freq: Int, startOn: Boolean = false) extends Module { + val io = IO(new Bundle { + val led0 = Output(Bool()) + }) + // Blink LED every second using Chisel built-in util.Counter + val led = RegInit(startOn.B) + val (_, counterWrap) = Counter(true.B, freq / 2) + when(counterWrap) { + led := ~led + } + io.led0 := led +} +object Main extends App { + // These lines generate the Verilog output + println( + new (chisel3.stage.ChiselStage).emitVerilog( + new Blinky(1000), + Array( + "--emission-options=disableMemRandomization,disableRegisterRandomization" + ) + ) + ) +} +``` + +Should output the following Verilog: +<details> +<summary>Click to expand!</summary> + +<pre class="hljs"><code><div><span class="hljs-keyword">module</span> Blinky( + <span class="hljs-keyword">input</span> clock, + <span class="hljs-keyword">input</span> reset, + <span class="hljs-keyword">output</span> io_led0 +); + <span class="hljs-keyword">reg</span> led; <span class="hljs-comment">// @[main.scala 11:20]</span> + <span class="hljs-keyword">reg</span> [<span class="hljs-number">8</span>:<span class="hljs-number">0</span>] counterWrap_value; <span class="hljs-comment">// @[Counter.scala 62:40]</span> + <span class="hljs-keyword">wire</span> counterWrap_wrap_wrap = counterWrap_value == <span class="hljs-number">9'h1f3</span>; <span class="hljs-comment">// @[Counter.scala 74:24]</span> + <span class="hljs-keyword">wire</span> [<span class="hljs-number">8</span>:<span class="hljs-number">0</span>] <span class="hljs-number">_</span>counterWrap_wrap_value_T_1 = counterWrap_value + <span class="hljs-number">9'h1</span>; <span class="hljs-comment">// @[Counter.scala 78:24]</span> + <span class="hljs-keyword">assign</span> io_led0 = led; <span class="hljs-comment">// @[main.scala 16:11]</span> + <span class="hljs-keyword">always</span> @(<span class="hljs-keyword">posedge</span> clock) <span class="hljs-keyword">begin</span> + <span class="hljs-keyword">if</span> (reset) <span class="hljs-keyword">begin</span> <span class="hljs-comment">// @[main.scala 11:20]</span> + led <= <span class="hljs-number">1'h0</span>; <span class="hljs-comment">// @[main.scala 11:20]</span> + <span class="hljs-keyword">end</span> <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (counterWrap_wrap_wrap) <span class="hljs-keyword">begin</span> <span class="hljs-comment">// @[main.scala 13:21]</span> + led <= ~led; <span class="hljs-comment">// @[main.scala 14:9]</span> + <span class="hljs-keyword">end</span> + <span class="hljs-keyword">if</span> (reset) <span class="hljs-keyword">begin</span> <span class="hljs-comment">// @[Counter.scala 62:40]</span> + counterWrap_value <= <span class="hljs-number">9'h0</span>; <span class="hljs-comment">// @[Counter.scala 62:40]</span> + <span class="hljs-keyword">end</span> <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (counterWrap_wrap_wrap) <span class="hljs-keyword">begin</span> <span class="hljs-comment">// @[Counter.scala 88:20]</span> + counterWrap_value <= <span class="hljs-number">9'h0</span>; <span class="hljs-comment">// @[Counter.scala 88:28]</span> + <span class="hljs-keyword">end</span> <span class="hljs-keyword">else</span> <span class="hljs-keyword">begin</span> + counterWrap_value <= <span class="hljs-number">_</span>counterWrap_wrap_value_T_1; <span class="hljs-comment">// @[Counter.scala 78:15]</span> + <span class="hljs-keyword">end</span> + <span class="hljs-keyword">end</span> +<span class="hljs-keyword">endmodule</span> +</div></code></pre> + +</details> + +### FIR Filter + +Consider an FIR filter that implements a convolution operation, as depicted in this block diagram: + +<img src="https://raw.githubusercontent.com/chipsalliance/chisel3/master/docs/src/images/fir_filter.svg?sanitize=true" width="512" /> + +While Chisel provides similar base primitives as synthesizable Verilog, and *could* be used as such: + +```scala +// 3-point moving sum implemented in the style of a FIR filter +class MovingSum3(bitWidth: Int) extends Module { + val io = IO(new Bundle { + val in = Input(UInt(bitWidth.W)) + val out = Output(UInt(bitWidth.W)) + }) + + val z1 = RegNext(io.in) + val z2 = RegNext(z1) + + io.out := (io.in * 1.U) + (z1 * 1.U) + (z2 * 1.U) +} +``` + +the power of Chisel comes from the ability to create generators, such as an FIR filter that is defined by the list of coefficients: + +```scala +// Generalized FIR filter parameterized by the convolution coefficients +class FirFilter(bitWidth: Int, coeffs: Seq[UInt]) extends Module { + val io = IO(new Bundle { + val in = Input(UInt(bitWidth.W)) + val out = Output(UInt(bitWidth.W)) + }) + // Create the serial-in, parallel-out shift register + val zs = Reg(Vec(coeffs.length, UInt(bitWidth.W))) + zs(0) := io.in + for (i <- 1 until coeffs.length) { + zs(i) := zs(i-1) + } + + // Do the multiplies + val products = VecInit.tabulate(coeffs.length)(i => zs(i) * coeffs(i)) + + // Sum up the products + io.out := products.reduce(_ + _) +} +``` + +and use and re-use them across designs: + +```scala +val movingSum3Filter = Module(new FirFilter(8, Seq(1.U, 1.U, 1.U))) // same 3-point moving sum filter as before +val delayFilter = Module(new FirFilter(8, Seq(0.U, 1.U))) // 1-cycle delay as a FIR filter +val triangleFilter = Module(new FirFilter(8, Seq(1.U, 2.U, 3.U, 2.U, 1.U))) // 5-point FIR filter with a triangle impulse response +``` + +The above can be converted to Verilog using `ChiselStage`: + +```scala +import chisel3.stage.{ChiselStage, ChiselGeneratorAnnotation} + +(new chisel3.stage.ChiselStage).execute( + Array("-X", "verilog"), + Seq(ChiselGeneratorAnnotation(() => new FirFilter(8, Seq(1.U, 1.U, 1.U))))) +``` + +Alternatively, you may generate some Verilog directly for inspection: + +```scala +val verilogString = chisel3.emitVerilog(new FirFilter(8, Seq(0.U, 1.U))) +println(verilogString) +``` + +## Getting Started + +### Bootcamp Interactive Tutorial + +The [**online Chisel Bootcamp**](https://mybinder.org/v2/gh/freechipsproject/chisel-bootcamp/master) is the recommended way to get started with and learn Chisel. +**No setup is required** (it runs in the browser), nor does it assume any prior knowledge of Scala. + +The [**classic Chisel tutorial**](https://github.com/ucb-bar/chisel-tutorial) contains small exercises and runs on your computer. + +### A Textbook on Chisel + +If you like a textbook to learn Chisel and also a bit of digital design in general, you may be interested in reading [**Digital Design with Chisel**](http://www.imm.dtu.dk/~masca/chisel-book.html). It is available in English, Chinese, Japanese, and Vietnamese. + +### Build Your Own Chisel Projects + +See [the setup instructions](SETUP.md) for how to set up your environment to build Chisel locally. + +When you're ready to build your own circuits in Chisel, **we recommend starting from the [Chisel Template](https://github.com/freechipsproject/chisel-template) repository**, which provides a pre-configured project, example design, and testbench. +Follow the [chisel-template README](https://github.com/freechipsproject/chisel-template) to get started. + +If you insist on setting up your own project from scratch, your project needs to depend on both the chisel3-plugin (Scalac plugin) and the chisel3 library. +For example, in SBT this could be expressed as: + +```scala +// build.sbt +scalaVersion := "2.13.8" +addCompilerPlugin("edu.berkeley.cs" % "chisel3-plugin" % "3.5.4" cross CrossVersion.full) +libraryDependencies += "edu.berkeley.cs" %% "chisel3" % "3.5.4" +// We also recommend using chiseltest for writing unit tests +libraryDependencies += "edu.berkeley.cs" %% "chiseltest" % "0.5.4" % "test" +``` + +### Guide For New Contributors + +If you are trying to make a contribution to this project, please read [CONTRIBUTING.md](https://github.com/chipsalliance/chisel3/blob/master/CONTRIBUTING.md) + +### Design Verification + +These simulation-based verification tools are available for Chisel: + +* [**chiseltest**](https://github.com/ucb-bar/chiseltest) is the batteries-included testing and formal verification library for Chisel-based RTL designs and a replacement for the former PeekPokeTester, providing the same base constructs but with a streamlined interface and concurrency support with `fork` and `join` with internal and Verilator integration for simulations. + +## Documentation + +### Useful Resources + +* [**Cheat Sheet**](https://github.com/freechipsproject/chisel-cheatsheet/releases/latest/download/chisel_cheatsheet.pdf), a 2-page reference of the base Chisel syntax and libraries +* [**ScalaDoc**](https://www.chisel-lang.org/api/latest/chisel3/index.html), a listing, description, and examples of the functionality exposed by Chisel +* [**Gitter**](https://gitter.im/freechipsproject/chisel3), where you can ask questions or discuss anything Chisel +* [**Website**](https://www.chisel-lang.org) ([source](https://github.com/freechipsproject/www.chisel-lang.org/)) +* [**Scastie (3.5.3)**](https://scastie.scala-lang.org/O3LqeVH7SWyIxD7bZRH8hA) +* [**asic-world**](http://www.asic-world.com/verilog/veritut.html) If you aren't familiar with verilog, this is a good tutorial. + +If you are migrating from Chisel2, see [the migration guide](https://www.chisel-lang.org/chisel3/chisel3-vs-chisel2.html). + +### Chisel Dev Meeting + +Chisel/FIRRTL development meetings happen every Monday from 1100--1200 PT. + +Call-in info and meeting notes are available [here](https://docs.google.com/document/d/1BLP2DYt59DqI-FgFCcjw8Ddl4K-WU0nHmQu0sZ_wAGo/). + +### Data Types Overview + +These are the base data types for defining circuit components: + + + +## Contributor Documentation + +This section describes how to get started contributing to Chisel itself, including how to test your version locally against other projects that pull in Chisel using [sbt's managed dependencies](https://www.scala-sbt.org/1.x/docs/Library-Dependencies.html). + +### Useful Resources for Contributors + +The [Useful Resources](#useful-resources) for users are also helpful for contributors. + +* [**Chisel Breakdown Slides**](https://docs.google.com/presentation/d/114YihixFBPCfUnv1inqAL8UjsiWfcNWdPHX7SeqlRQc), an introductory talk about Chisel's internals + +### Compiling and Testing Chisel + +You must first install required dependencies to build Chisel locally, please see [the setup instructions](SETUP.md). + +Clone and build the Chisel library: + +```bash +git clone https://github.com/chipsalliance/chisel3.git +cd chisel3 +sbt compile +``` + +In order to run the following unit tests, you will need several tools on your `PATH`, namely +[verilator](https://www.veripool.org/verilator/), +[yosys](http://www.clifford.at/yosys/), +[espresso](https://github.com/chipsalliance/espresso), +and [z3](https://github.com/Z3Prover/z3). +Check that each is installed on your `PATH` by running `which verilator` and so on. + +If the compilation succeeded and the dependencies noted above are installed, you can then run the included unit tests by invoking: + +```bash +sbt test +``` + +### Running Projects Against Local Chisel + +To use the development version of Chisel (`master` branch), you will need to build from source and `publishLocal`. +The repository version can be found in the [build.sbt](build.sbt) file. +As of the time of writing it was: + +```scala +version := "3.5-SNAPSHOT" +``` + +To publish your version of Chisel to the local Ivy (sbt's dependency manager) repository, run: + +```bash +sbt publishLocal +``` + +The compiled version gets placed in `~/.ivy2/local/edu.berkeley.cs/`. +If you need to un-publish your local copy of Chisel, remove the directory generated in `~/.ivy2/local/edu.berkeley.cs/`. + +In order to have your projects use this version of Chisel, you should update the `libraryDependencies` setting in your project's build.sbt file to: + +```scala +libraryDependencies += "edu.berkeley.cs" %% "chisel3" % "3.5-SNAPSHOT" +``` + +### Building Chisel with FIRRTL in the same SBT Project + +While we recommend using the library dependency approach as described above, it is possible to build Chisel and FIRRTL in a single SBT project. + +**Caveats**: + +* This only works for the "main" configuration; you cannot build the Chisel tests this way because `treadle` is only supported as a library dependency. +* Do not `publishLocal` when building this way. The published artifact will be missing the FIRRTL dependency. + +This works by using [sbt-sriracha](http://eed3si9n.com/hot-source-dependencies-using-sbt-sriracha), an SBT plugin for toggling between source and library dependencies. +It provides two JVM system properties that, when set, will tell SBT to include FIRRTL as a source project: + +* `sbt.sourcemode` - when set to true, SBT will look for FIRRTL in the workspace +* `sbt.workspace` - sets the root directory of the workspace + +Example use: + +```bash +# From root of this repo +git clone git@github.com:chipsalliance/firrtl.git +sbt -Dsbt.sourcemode=true -Dsbt.workspace=$PWD +``` + +This is primarily useful for building projects that themselves want to include Chisel as a source dependency. +As an example, see [Rocket Chip](https://github.com/chipsalliance/rocket-chip) + +### Chisel3 Architecture Overview + +The Chisel3 compiler consists of these main parts: + +* **The frontend**, `chisel3.*`, which is the publicly visible "API" of Chisel and what is used in Chisel RTL. These just add data to the... +* **The Builder**, `chisel3.internal.Builder`, which maintains global state (like the currently open Module) and contains commands, generating... +* **The intermediate data structures**, `chisel3.firrtl.*`, which are syntactically very similar to Firrtl. Once the entire circuit has been elaborated, the top-level object (a `Circuit`) is then passed to... +* **The Firrtl emitter**, `chisel3.firrtl.Emitter`, which turns the intermediate data structures into a string that can be written out into a Firrtl file for further processing. + +Also included is: + +* **The standard library** of circuit generators, `chisel3.util.*`. These contain commonly used interfaces and constructors (like `Decoupled`, which wraps a signal with a ready-valid pair) as well as fully parameterizable circuit generators (like arbiters and multiplexors). +* **Chisel Stage**, `chisel3.stage.*`, which contains compilation and test functions that are invoked in the standard Verilog generation and simulation testing infrastructure. These can also be used as part of custom flows. + +### Chisel Sub-Projects + +Chisel consists of 4 Scala projects; each is its own separate compilation unit: + +* [`core`](core) is the bulk of the source code of Chisel, depends on `macros` +* [`src/main`](src/main) is the "main" that brings it all together and includes a [`util`](src/main/scala/chisel3/util) library, which depends on `core` +* [`plugin`](plugin) is the compiler plugin, no internal dependencies +* [`macros`](macros) is most of the macros used in Chisel, no internal dependencies + +Code that touches lots of APIs that are private to the `chisel3` package should belong in `core`, while code that is pure Chisel should belong in `src/main`. + +### Which version should I use? + +We encourage Chisel users (as opposed to Chisel developers), to use the latest release version of Chisel. +This [chisel-template](https://github.com/freechipsproject/chisel-template) repository is kept up-to-date, depending on the most recent version of Chisel. +The recommended version is also captured near the top of this README, and in the [Github releases](https://github.com/chipsalliance/chisel3/releases) section of this repo. +If you encounter an issue with a released version of Chisel, please file an issue on GitHub mentioning the Chisel version and provide a simple test case (if possible). +Try to reproduce the issue with the associated latest minor release (to verify that the issue hasn't been addressed). + +For more information on our versioning policy and what versions of the various Chisel ecosystem projects work together, see [Chisel Project Versioning](https://www.chisel-lang.org/chisel3/docs/appendix/versioning.html). + +If you're developing a Chisel library (or `chisel3` itself), you'll probably want to work closer to the tip of the development trunk. +By default, the master branches of the chisel repositories are configured to build and publish their version of the code as `Z.Y-SNAPSHOT`. +Updated SNAPSHOTs are publised on every push to master. +You are encouraged to do your development against the latest SNAPSHOT, but note that neither API nor ABI compatibility is guaranteed so your code may break at any time. + +### Roadmap + +See [ROADMAP.md]. |
