37 lines
830 B
Scala
37 lines
830 B
Scala
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package util
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import Chisel._
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import cde.Parameters
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// Produces 0-width value when counting to 1
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class ZCounter(val n: Int) {
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val value = Reg(init=UInt(0, log2Ceil(n)))
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def inc(): Bool = {
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if (n == 1) Bool(true)
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else {
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val wrap = value === UInt(n-1)
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value := Mux(Bool(!isPow2(n)) && wrap, UInt(0), value + UInt(1))
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wrap
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}
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}
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}
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object ZCounter {
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def apply(n: Int) = new ZCounter(n)
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def apply(cond: Bool, n: Int): (UInt, Bool) = {
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val c = new ZCounter(n)
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var wrap: Bool = null
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when (cond) { wrap = c.inc() }
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(c.value, cond && wrap)
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}
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}
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object TwoWayCounter {
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def apply(up: Bool, down: Bool, max: Int): UInt = {
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val cnt = Reg(init = UInt(0, log2Up(max+1)))
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when (up && !down) { cnt := cnt + UInt(1) }
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when (down && !up) { cnt := cnt - UInt(1) }
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cnt
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}
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}
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