# Getting Started

Calyx is an intermediate language and infrastructure for building compilers
that generate custom hardware accelerators.
These instructions will help you set up the Calyx compiler and associated
tools.
By the end, you should be able to compile and simulate hardware designs
generated by Calyx.

## Compiler Installation

Install [Rust][rust] (it should automatically install `cargo`).

Clone the repository:
```
git clone https://github.com/cucapra/calyx.git
```
Then build the compiler:
```
cargo build
```

You can invoke the compiler in one of two ways:
```
cargo run -- --help # Rebuilds the compiler if the sources changed
./target/debug/futil --help # Default debug build of the compiler
```

## Running Core Tests

The core test suites tests the Calyx compiler passes.
Install the following tools for running the core tests:
  1. [runt][] hosts our testing infrastructure. Install with:
  `cargo install runt`
  2. [jq][] is a command-line JSON processor:
     * Ubuntu: `sudo apt install jq`
     * Mac: `brew install jq`
     * Other platforms: [JQ installation][jq-install]

Build the compiler:
```
cargo build
```
Then run the core tests with:
```
runt -i core
```

If everything has been installed correctly, this should not produce any failing
tests.

## Installing the Command-line Driver

[The Calyx driver](./fud) wraps the various compiler frontends and
backends to simplify running Calyx programs.

Install [Flit][]:
```
pip3 install flit
```

Install `fud` (from the root of the repository):
```
flit -f fud/pyproject.toml install -s
```
Configure `fud`:
```
fud config global.futil_directory <full path to Calyx repository>
```
Check the `fud` configuration:
```
fud check
```

`fud` will report certain tools are not available. This is expected.

## Simulating with Verilator

[Verilator][] is the default simulation backend for Calyx. If you want to
run your Calyx programs, you need to install Verilator.

On a Mac, install with:
```
brew install verilator
```

Otherwise, you will probably need to compile it from source yourself (the versions in Linux repositories are generally out of date).
There instructions are stolen from [Verilator's installation instructions][verilator-install]:
```
git clone https://github.com/verilator/verilator
cd verilator
git pull
git checkout master
autoconf
./configure
make
sudo make install
```

Use `fud` to check you have the right version:
```
fud check
```
`fud` should report that the `verilator` binary was installed and has the
right version.
Some tools will be reported missing. This is expected.

### Generating Simulation Results

By default, simulating with Verilator will produce a [VCD file][vcd] which
is not human-readable.
Our tests use [vcdump][] to transform VCD file into JSON files.

Install vcdump:
```
cargo install vcdump
```
Use `fud` to check the right version was installed:
```
fud check
```

It should report that the `vcdump` binary is available and has the right
version.
Some tools will be reported missing. This is expected.

## Running a Hardware Design

We're all set to run a Calyx hardware design now. Run the following command:
```
fud e examples/tutorial/language-tutorial-iterate.futil \
  -s verilog.data examples/tutorial/data.json \
  --to dat -v
```

This command will compile `examples/tutorial/language-tutorial-iterate.futil` to Verilog
using the Calyx compiler, simulate the design using the data in `examples/tutorial/data.json`, and generate a JSON representation of the
final memory state.

Congratulations! You've simulated your first hardware design with Calyx.

## Where to go next?

- [How does the language work?](./tutorial/language-tut.md)
- [How do I install Calyx frontends?](./fud/index.html#dahlia-fronted)
- [Examples with `fud`](./fud/examples.md)
- [How do I write a frontend for Calyx?](./tutorial/frontend-tut.md)


[rust]: https://doc.rust-lang.org/cargo/getting-started/installation.html
[runt]: https://github.com/rachitnigam/runt
[vcdump]: https://github.com/sgpthomas/vcdump
[verilator]: https://www.veripool.org/wiki/verilator
[verilator-install]: https://www.veripool.org/projects/verilator/wiki/Installing
[jq]: https://stedolan.github.io/jq/
[jq-install]: https://stedolan.github.io/jq/
[frontends]: ./frontends/index.md
[calyx-py]: ./calyx-py.md
[flit]: https://flit.readthedocs.io/en/latest/
[vcd]: https://en.wikipedia.org/wiki/Value_change_dump
[dahlia]: https://github.com/cucapra/dahlia
[dahlia-install]: https://github.com/cucapra/dahlia#set-it-up
[sbt]: https://www.scala-sbt.org/download.html