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util: tweak rational crossings to avoid mux in source

This commit is contained in:
Yunsup Lee 2017-07-30 22:31:19 -07:00
parent ea1840c4b1
commit cb3529bbc3

View File

@ -49,7 +49,8 @@ case object SlowToFast extends RationalDirection {
final class RationalIO[T <: Data](gen: T) extends Bundle
{
val bits = gen.chiselCloneType
val bits0 = gen.chiselCloneType
val bits1 = gen.chiselCloneType
val valid = Bool()
val source = UInt(width = 2)
val ready = Bool().flip
@ -83,7 +84,8 @@ class RationalCrossingSource[T <: Data](gen: T, direction: RationalDirection = S
deq.valid := enq.valid
deq.source := count
deq.bits := Mux(equal, enq.bits, RegEnable(enq.bits, equal))
deq.bits0 := enq.bits
deq.bits1 := RegEnable(enq.bits, equal)
enq.ready := Mux(equal, deq.ready, count(1) =/= deq.sink(0))
when (enq.fire()) { count := Cat(count(0), !count(1)) }
@ -118,7 +120,7 @@ class RationalCrossingSink[T <: Data](gen: T, direction: RationalDirection = Sym
enq.ready := deq.ready
enq.sink := count
deq.bits := enq.bits
deq.bits := Mux(equal, enq.bits0, enq.bits1)
deq.valid := Mux(equal, enq.valid, count(1) =/= enq.source(0))
when (deq.fire()) { count := Cat(count(0), !count(1)) }
@ -160,7 +162,7 @@ object ToRational
object FromRational
{
def apply[T <: Data](x: RationalIO[T], direction: RationalDirection = Symmetric): DecoupledIO[T] = {
val sink = Module(new RationalCrossingSink(x.bits, direction))
val sink = Module(new RationalCrossingSink(x.bits0, direction))
sink.io.enq <> x
sink.io.deq
}