dependentChisel

This is the impl for Master thesis : Dependent Chisel: Statically-checked hardware designs based on Chisel and Scala 3, by Yuchen du https://github.com/doofin/dependentChisel/blob/master/Msc_Thesis_yuchen.pdf

It uses partial dependent types in Scala 3 to provide early error message for Chisel, a hardware description language embedded in Scala. This allows you to identify bitwidth mismatch at compile time where IDE can show errors instantly in the editor.

examples

examples like adder, etc. can be found in src/test/scala/dependentChisel/

some inline examples:

  class Adder1(using GlobalInfo) extends UserModule {
    val a = newIO[2](VarType.Input)
    val b = newIO[2](VarType.Input)
    val y = newIO[2](VarType.Output)

    y := a + b
  }

A parameterized adder with static guarante:

  class AdderParm[I <: Int: ValueOf](using GlobalInfo) extends UserModule {
    val a = newInput[I]("a")
    val b = newInput[I]("b")
    val y = newOutput[I]("y")

    y := a + b
  }

Instantiate those modules :

  class AdderComb4(using parent: GlobalInfo) extends UserModule {

    val a = newInput[2]("a")
    val b = newInput[2]("b")
    val c = newInput[2]("c")
    val d = newInput[2]("d")
    val y = newOutput[2]("y")

    val m1 = newMod(new AdderParm[2])
    val m2 = newMod(new AdderParm[2])

    m1.a := a
    m1.b := b
    m2.a := c
    m2.b := d

    y := m1.y + m2.y
  }

Interop with chisel

The current implementation is based on Chisel 3.5.1, which is used internally. There's no direct interop with the original Chisel, but you can probably use the generated FIRRTL for that.

Although scala 3 can invoke scala 2.13 libraries,chisel uses scala 2 macros different from scala 3 ,making it partially incompatible.

To fix the mismatch, there are several possible ways:

• Rewrite all macros and make everything compatible.
• Rewrite some macros and extend some base class.
• Write a new frontend and emit FIRRTL.

compile and run

This is a sbt project for Scala 3

run : `sbt run`
compile : `sbt compile` 

many tests under src/test can be run by sbt test

IDE support

Metals with vscode

IntelliJ

theories and related work

related work : https://github.com/doofin/dependentChisel/blob/master/resources.md

misc

with

git ls-files | grep '\.scala$' | xargs wc -l

chisel has 60927 total loc