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ReduceOthers: remove constants from the balanced AND tree

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This commit is contained in:
Wesley W. Terpstra 2017-06-23 00:28:05 -07:00
parent 48611266fa
commit 2d8b2f4edd
2 changed files with 41 additions and 13 deletions
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9
src/main/scala/regmapper/RegMapper.scala
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@ -135,11 +135,12 @@ object RegMapper
val data = if (field.write.combinational) back.bits.data else front.bits.data val data = if (field.write.combinational) back.bits.data else front.bits.data
val (f_riready, f_rovalid, f_data) = field.read.fn(rivalid(i) && rimask, roready(i) && romask) val (f_riready, f_rovalid, f_data) = field.read.fn(rivalid(i) && rimask, roready(i) && romask)
val (f_wiready, f_wovalid) = field.write.fn(wivalid(i) && wimask, woready(i) && womask, data(high, low)) val (f_wiready, f_wovalid) = field.write.fn(wivalid(i) && wimask, woready(i) && womask, data(high, low))
def litOR(x: Bool, y: Bool) = if (x.isLit && x.litValue == 1) Bool(true) else x || y
// Add this field to the ready-valid signals for the register // Add this field to the ready-valid signals for the register
rifire(reg) = (rivalid(i), f_riready || !rimask) +: rifire(reg) rifire(reg) = (rivalid(i), litOR(f_riready, !rimask)) +: rifire(reg)
wifire(reg) = (wivalid(i), f_wiready || !wimask) +: wifire(reg) wifire(reg) = (wivalid(i), litOR(f_wiready, !wimask)) +: wifire(reg)
rofire(reg) = (roready(i), f_rovalid || !romask) +: rofire(reg) rofire(reg) = (roready(i), litOR(f_rovalid, !romask)) +: rofire(reg)
wofire(reg) = (woready(i), f_wovalid || !womask) +: wofire(reg) wofire(reg) = (woready(i), litOR(f_wovalid, !womask)) +: wofire(reg)
dataOut(reg) = dataOut(reg) | ((f_data << low) & (~UInt(0, width = high+1))) dataOut(reg) = dataOut(reg) | ((f_data << low) & (~UInt(0, width = high+1)))
} }

45
src/main/scala/util/ReduceOthers.scala
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@ -1,4 +1,4 @@
// See LICENSE.Berkeley for license details. // See LICENSE.SiFive for license details.
package util package util
import Chisel._ import Chisel._
@ -7,16 +7,29 @@ object ReduceOthers {
// Given a list of bools, create this output: // Given a list of bools, create this output:
// out[i] = AND[j=0..out.size, j!=i] in[j] // out[i] = AND[j=0..out.size, j!=i] in[j]
def apply(x: Seq[Bool]): Seq[Bool] = { def apply(x: Seq[Bool]): Seq[Bool] = {
if (x.size <= 1) { val (literals, variables) = x.partition(_.isLit)
Seq.fill(x.size) { Bool(true) }
} else if (x.size <= 3) { val falses = literals.count(_.litValue == 0)
Seq.tabulate(x.size) { i => if (falses > 2) {
(x.take(i) ++ x.drop(i+1)).reduce(_ && _) Seq.fill(x.size) { Bool(false) }
} else if (falses == 1) {
x.map { b =>
if (b.isLit && b.litValue == 0) {
variables.foldLeft(Bool(true))(_ && _)
} else {
Bool(false)
}
} }
} else { } else {
val half = ReduceOthers(x.grouped(2).map(_.reduce(_ && _)).toList) var (out, all) = helper(variables)
Seq.tabulate(x.size) { i => x.map { b =>
if ((i ^ 1) >= x.size) half(i/2) else x(i ^ 1) && half(i / 2) if (b.isLit) {
all
} else {
val sel = out.head
out = out.tail
sel
}
} }
} }
} }
@ -24,4 +37,18 @@ object ReduceOthers {
def apply(x: Seq[(Bool, Bool)]) { def apply(x: Seq[(Bool, Bool)]) {
(x.map(_._1) zip apply(x.map(_._2))) foreach { case (w, x) => w := x } (x.map(_._1) zip apply(x.map(_._2))) foreach { case (w, x) => w := x }
} }
private def helper(x: Seq[Bool]): (Seq[Bool], Bool) = {
if (x.size <= 1) {
(Seq.fill(x.size) { Bool(true) }, x.headOption.getOrElse(Bool(true)))
} else if (x.size <= 3) {
(Seq.tabulate(x.size) { i =>
(x.take(i) ++ x.drop(i+1)).reduce(_ && _)
}, x.reduce(_ && _))
} else {
val (half, all) = helper(x.grouped(2).map(_.reduce(_ && _)).toList)
(Seq.tabulate(x.size) { i =>
if ((i ^ 1) >= x.size) half(i/2) else x(i ^ 1) && half(i / 2)
}, all)
}
}
} }