56 lines
1.5 KiB
Scala
56 lines
1.5 KiB
Scala
// See LICENSE.SiFive for license details.
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package freechips.rocketchip.util
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import Chisel._
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object ReduceOthers {
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// Given a list of bools, create this output:
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// out[i] = AND[j=0..out.size, j!=i] in[j]
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def apply(x: Seq[Bool]): Seq[Bool] = {
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val (literals, variables) = x.partition(_.isLit)
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val falses = literals.count(_.litValue == 0)
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if (falses > 2) {
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Seq.fill(x.size) { Bool(false) }
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} else if (falses == 1) {
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x.map { b =>
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if (b.isLit && b.litValue == 0) {
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variables.foldLeft(Bool(true))(_ && _)
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} else {
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Bool(false)
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}
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}
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} else {
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var (out, all) = helper(variables)
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x.map { b =>
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if (b.isLit) {
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all
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} else {
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val sel = out.head
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out = out.tail
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sel
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}
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}
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}
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}
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// Take pairs of (output_wire, input_bool)
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def apply(x: Seq[(Bool, Bool)]) {
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(x.map(_._1) zip apply(x.map(_._2))) foreach { case (w, x) => w := x }
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}
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private def helper(x: Seq[Bool]): (Seq[Bool], Bool) = {
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if (x.size <= 1) {
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(Seq.fill(x.size) { Bool(true) }, x.headOption.getOrElse(Bool(true)))
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} else if (x.size <= 3) {
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(Seq.tabulate(x.size) { i =>
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(x.take(i) ++ x.drop(i+1)).reduce(_ && _)
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}, x.reduce(_ && _))
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} else {
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val (half, all) = helper(x.grouped(2).map(_.reduce(_ && _)).toList)
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(Seq.tabulate(x.size) { i =>
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if ((i ^ 1) >= x.size) half(i/2) else x(i ^ 1) && half(i / 2)
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}, all)
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}
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}
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}
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