References:
Based on Java Virtual Machine (JVM).
Scala – .class – JVM
Scala designed for Domain-Specific Language developers: can build your own language based on Scala.
class or function definition can have type paramters, in order to define class/functions with arbitrary types.
e.g. the following defines a function myMux which accepts inputs of any type of tPath and fPath
def myMux [T <: Data ]( sel: Bool , tPath: T, fPath: T): T = {
val ret = WireDefault (fPath)
when (sel) {
ret := tPath
}
r et
}The expression in the square brackets [T <: Data] defines a type parameter T that is Data
or a subclass of Data . Data is the root of the Chisel type system.
// generators/chipyard/src/main/scala/HarnessBinders.scala
class HarnessBinder[T, S <: HasHarnessSignalReferences, U <: Data](composer: ((T, S, Seq[U]) => Unit) => (T, S, Seq[U]) => Unit)(implicit systemTag: ClassTag[T], harnessTag: ClassTag[S], portTag: ClassTag[U]) extends Config((site, here, up) => {
case HarnessBinders => up(HarnessBinders, site) + (systemTag.runtimeClass.toString ->
((t: Any, th: HasHarnessSignalReferences, ports: Seq[Data]) => {
val pts = ports.collect({case p: U => p})
require (pts.length == ports.length, s"Port type mismatch between IOBinder and HarnessBinder: ${portTag}")
val upfn = up(HarnessBinders, site)(systemTag.runtimeClass.toString)
th match {
case th: S =>
t match {
case system: T => composer(upfn)(system, th, pts)
case _ =>
}
case _ =>
}
})
)
})
If you could revise
the fundmental principles of
computer system design
to improve security...
... what would you change?