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// See LICENSE for license details.
/** Wrappers for valid interfaces and associated circuit generators using them.
*/
package Chisel
/** An I/O Bundle containing data and a signal determining if it is valid */
class ValidIO[+T <: Data](gen2: T) extends Bundle
{
val valid = Bool(OUTPUT)
val bits = gen2.cloneType.asOutput
def fire(dummy: Int = 0): Bool = valid
override def cloneType: this.type = new ValidIO(gen2).asInstanceOf[this.type]
}
/** Adds a valid protocol to any interface. The standard used is
that the consumer uses the flipped interface.
*/
object Valid {
def apply[T <: Data](gen: T): ValidIO[T] = new ValidIO(gen)
}
/** A hardware module that delays data coming down the pipeline
by the number of cycles set by the latency parameter. Functionality
is similar to ShiftRegister but this exposes a Pipe interface.
Example usage:
val pipe = new Pipe(UInt())
pipe.io.enq <> produce.io.out
consumer.io.in <> pipe.io.deq
*/
object Pipe
{
def apply[T <: Data](enqValid: Bool, enqBits: T, latency: Int): ValidIO[T] = {
if (latency == 0) {
val out = Wire(Valid(enqBits))
out.valid <> enqValid
out.bits <> enqBits
out
} else {
val v = Reg(Bool(), next=enqValid, init=Bool(false))
val b = RegEnable(enqBits, enqValid)
apply(v, b, latency-1)
}
}
def apply[T <: Data](enqValid: Bool, enqBits: T): ValidIO[T] = apply(enqValid, enqBits, 1)
def apply[T <: Data](enq: ValidIO[T], latency: Int = 1): ValidIO[T] = apply(enq.valid, enq.bits, latency)
}
class Pipe[T <: Data](gen: T, latency: Int = 1) extends Module
{
val io = new Bundle {
val enq = Valid(gen).flip
val deq = Valid(gen)
}
io.deq <> Pipe(io.enq, latency)
}
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