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ShiftQueue: use Vec of Bool to support constant prop of enq.valid

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This commit is contained in:
Wesley W. Terpstra
2017-07-18 14:20:04 -07:00
parent 6d0821f19a
commit c0a3bb58e9
1 changed files with 9 additions and 5 deletions
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14
src/main/scala/util/ShiftQueue.scala
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@@ -17,8 +17,7 @@ class ShiftQueue[T <: Data](gen: T,
val mask = UInt(OUTPUT, entries)
})
private val ram = Mem(entries, gen)
private val valid = RegInit(UInt(0, entries))
private val valid = RegInit(Vec.fill(entries) { Bool(false) })
private val elts = Reg(Vec(entries, gen))
private val do_enq = io.enq.fire()
@@ -30,7 +29,12 @@ class ShiftQueue[T <: Data](gen: T,
val enqNew = io.enq.fire() && Mux(io.deq.ready, valid(i), !valid(i) && (if (i == 0) true.B else valid(i-1)))
when (shiftDown || enqNew) { elts(i) := wdata }
}
when (do_enq =/= do_deq) { valid := Mux(do_enq, (valid << 1) | UInt(1), valid >> 1) }
val padded = Seq(true.B) ++ valid ++ Seq(false.B)
for (i <- 0 until entries) {
when ( do_enq && !do_deq && padded(i+0)) { valid(i) := true.B }
when (!do_enq && do_deq && !padded(i+2)) { valid(i) := false.B }
}
io.enq.ready := !valid(entries-1)
io.deq.valid := valid(0)
@@ -45,6 +49,6 @@ class ShiftQueue[T <: Data](gen: T,
when (io.deq.ready) { io.enq.ready := true.B }
}
io.count := PopCount(valid)
io.mask := valid
io.mask := valid.asUInt
io.count := PopCount(io.mask)
}