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// See LICENSE for license details.
/** Conditional blocks.
*/
package Chisel
import scala.language.reflectiveCalls
import scala.language.experimental.macros
import scala.reflect.runtime.universe._
import scala.reflect.macros.blackbox._
/** This is identical to [[Chisel.when when]] with the condition inverted */
object unless { // scalastyle:ignore object.name
def apply(c: Bool)(block: => Unit) {
when (!c) { block }
}
}
class SwitchContext[T <: Bits](cond: T) {
def is(v: Iterable[T])(block: => Unit) {
if (!v.isEmpty) when (v.map(_.asUInt === cond.asUInt).reduce(_||_)) { block }
}
def is(v: T)(block: => Unit) { is(Seq(v))(block) }
def is(v: T, vr: T*)(block: => Unit) { is(v :: vr.toList)(block) }
}
/** An object for separate cases in [[Chisel.switch switch]]
* It is equivalent to a [[Chisel.when$ when]] block comparing to the condition
* Use outside of a switch statement is illegal */
object is { // scalastyle:ignore object.name
// Begin deprecation of non-type-parameterized is statements.
def apply(v: Iterable[Bits])(block: => Unit) {
require(false, "The 'is' keyword may not be used outside of a switch.")
}
def apply(v: Bits)(block: => Unit) {
require(false, "The 'is' keyword may not be used outside of a switch.")
}
def apply(v: Bits, vr: Bits*)(block: => Unit) {
require(false, "The 'is' keyword may not be used outside of a switch.")
}
}
/** Conditional logic to form a switch block
* @example
* {{{ ... // default values here
* switch ( myState ) {
* is( state1 ) {
* ... // some logic here
* }
* is( state2 ) {
* ... // some logic here
* }
* } }}}*/
object switch { // scalastyle:ignore object.name
def apply[T <: Bits](cond: T)(x: => Unit): Unit = macro impl
def impl(c: Context)(cond: c.Tree)(x: c.Tree): c.Tree = { import c.universe._
val sc = c.universe.internal.reificationSupport.freshTermName("sc")
def extractIsStatement(tree: Tree): List[c.universe.Tree] = tree match {
case q"Chisel.is.apply( ..$params )( ..$body )" => List(q"$sc.is( ..$params )( ..$body )")
case b => throw new Exception(s"Cannot include blocks that do not begin with is() in switch.")
}
val q"..$body" = x
val ises = body.flatMap(extractIsStatement(_))
q"""{ val $sc = new SwitchContext($cond); ..$ises }"""
}
}
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