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// See LICENSE for license details.
/** Conditional blocks.
*/
package chisel3.util
import scala.language.reflectiveCalls
import scala.language.experimental.macros
import scala.reflect.runtime.universe._
import scala.reflect.macros.blackbox._
import chisel3._
object unless { // scalastyle:ignore object.name
/** Does the same thing as [[when$ when]], but with the condition inverted.
*/
def apply(c: Bool)(block: => Unit) {
when (!c) { block }
}
}
/** Implementation details for [[switch]]. See [[switch]] and [[chisel3.util.is is]] for the
* user-facing API.
*/
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) }
}
/** Use to specify cases in a [[switch]] block, equivalent to a [[when$ when]] block comparing to
* the condition variable.
*
* @note illegal outside a [[switch]] block
* @note multiple conditions may fire simultaneously
* @note dummy implementation, a macro inside [[switch]] transforms this into the actual
* implementation
*/
object is { // scalastyle:ignore object.name
// TODO: Begin deprecation of non-type-parameterized is statements.
/** Executes `block` if the switch condition is equal to any of the values in `v`.
*/
def apply(v: Iterable[Bits])(block: => Unit) {
require(false, "The 'is' keyword may not be used outside of a switch.")
}
/** Executes `block` if the switch condition is equal to `v`.
*/
def apply(v: Bits)(block: => Unit) {
require(false, "The 'is' keyword may not be used outside of a switch.")
}
/** Executes `block` if the switch condition is equal to any of the values in the argument list.
*/
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. See [[is$ is]] for the case API.
*
* @example {{{
* switch (myState) {
* is (state1) {
* // some logic here that runs when myState === state1
* }
* is (state2) {
* // some logic here that runs when myState === state2
* }
* }
* }}}
*/
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 {
// TODO: remove when Chisel compatibility package is removed
case q"Chisel.`package`.is.apply( ..$params )( ..$body )" => List(q"$sc.is( ..$params )( ..$body )")
case q"chisel3.util.is.apply( ..$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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