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rocket-chip/rocket/src/main/scala/util.scala
2014-12-12 16:54:33 -08:00

161 lines
4.6 KiB
Scala

// See LICENSE for license details.
package rocket
import Chisel._
import uncore._
import scala.math._
class Unsigned(x: Int) {
require(x >= 0)
def clog2: Int = { require(x > 0); ceil(log(x)/log(2)).toInt }
def log2: Int = { require(x > 0); floor(log(x)/log(2)).toInt }
def isPow2: Boolean = x > 0 && (x & (x-1)) == 0
def nextPow2: Int = if (x == 0) 1 else 1 << clog2
}
object Util {
implicit def intToUInt(x: Int): UInt = UInt(x)
implicit def booleanToBool(x: Boolean): Bits = Bool(x)
implicit def intSeqToUIntSeq(x: Iterable[Int]): Iterable[UInt] = x.map(UInt(_))
implicit def seqToVec[T <: Data](x: Iterable[T]): Vec[T] = Vec(x)
implicit def wcToUInt(c: WideCounter): UInt = c.value
implicit def intToUnsigned(x: Int): Unsigned = new Unsigned(x)
implicit def booleanToIntConv(x: Boolean) = new AnyRef {
def toInt: Int = if (x) 1 else 0
}
}
import Util._
object Str
{
def apply(s: String): UInt = {
var i = BigInt(0)
require(s.forall(validChar _))
for (c <- s)
i = (i << 8) | c
UInt(i, s.length*8)
}
def apply(x: Char): UInt = {
require(validChar(x))
UInt(x.toInt, 8)
}
def apply(x: UInt): UInt = apply(x, 10)
def apply(x: UInt, radix: Int): UInt = {
val rad = UInt(radix)
val w = x.getWidth
require(w > 0)
var q = x
var s = digit(q % rad)
for (i <- 1 until ceil(log(2)/log(radix)*w).toInt) {
q = q / rad
s = Cat(Mux(Bool(radix == 10) && q === UInt(0), Str(' '), digit(q % rad)), s)
}
s
}
def apply(x: SInt): UInt = apply(x, 10)
def apply(x: SInt, radix: Int): UInt = {
val neg = x < SInt(0)
val abs = x.abs
if (radix != 10) {
Cat(Mux(neg, Str('-'), Str(' ')), Str(abs, radix))
} else {
val rad = UInt(radix)
val w = abs.getWidth
require(w > 0)
var q = abs
var s = digit(q % rad)
var needSign = neg
for (i <- 1 until ceil(log(2)/log(radix)*w).toInt) {
q = q / rad
val placeSpace = q === UInt(0)
val space = Mux(needSign, Str('-'), Str(' '))
needSign = needSign && !placeSpace
s = Cat(Mux(placeSpace, space, digit(q % rad)), s)
}
Cat(Mux(needSign, Str('-'), Str(' ')), s)
}
}
private def digit(d: UInt): UInt = Mux(d < UInt(10), Str('0')+d, Str(('a'-10).toChar)+d)(7,0)
private def validChar(x: Char) = x == (x & 0xFF)
}
object Split
{
// is there a better way to do do this?
def apply(x: Bits, n0: Int) = {
val w = checkWidth(x, n0)
(x(w-1,n0), x(n0-1,0))
}
def apply(x: Bits, n1: Int, n0: Int) = {
val w = checkWidth(x, n1, n0)
(x(w-1,n1), x(n1-1,n0), x(n0-1,0))
}
def apply(x: Bits, n2: Int, n1: Int, n0: Int) = {
val w = checkWidth(x, n2, n1, n0)
(x(w-1,n2), x(n2-1,n1), x(n1-1,n0), x(n0-1,0))
}
private def checkWidth(x: Bits, n: Int*) = {
val w = x.getWidth
def decreasing(x: Seq[Int]): Boolean =
if (x.tail.isEmpty) true
else x.head > x.tail.head && decreasing(x.tail)
require(decreasing(w :: n.toList))
w
}
}
// a counter that clock gates most of its MSBs using the LSB carry-out
case class WideCounter(width: Int, inc: UInt = UInt(1))
{
require(inc.getWidth > 0)
private val isWide = width > 2*inc.getWidth
private val smallWidth = if (isWide) inc.getWidth max log2Up(width) else width
private val small = Reg(init=UInt(0, smallWidth))
private val doInc = inc.orR
private val nextSmall =
if (inc.getWidth == 1) small + UInt(1, smallWidth+1)
else Cat(UInt(0,1), small) + inc
when (doInc) { small := nextSmall(smallWidth-1,0) }
private val large = if (isWide) {
val r = Reg(init=UInt(0, width - smallWidth))
when (doInc && nextSmall(smallWidth)) { r := r + UInt(1) }
r
} else null
val value = Cat(large, small)
def := (x: UInt) = {
val w = x.getWidth
small := x(w.min(smallWidth)-1,0)
if (isWide) large := (if (w < smallWidth) UInt(0) else x(w.min(width)-1,smallWidth))
}
}
object Random
{
def apply(mod: Int, random: UInt): UInt = {
if (isPow2(mod)) random(log2Up(mod)-1,0)
else PriorityEncoder(partition(apply(1 << log2Up(mod*8), random), mod))
}
def apply(mod: Int): UInt = apply(mod, randomizer)
def oneHot(mod: Int, random: UInt): UInt = {
if (isPow2(mod)) UIntToOH(random(log2Up(mod)-1,0))
else PriorityEncoderOH(partition(apply(1 << log2Up(mod*8), random), mod)).toBits
}
def oneHot(mod: Int): UInt = oneHot(mod, randomizer)
private def randomizer = LFSR16()
private def round(x: Double): Int =
if (x.toInt.toDouble == x) x.toInt else (x.toInt + 1) & -2
private def partition(value: UInt, slices: Int) =
Vec.tabulate(slices)(i => value < round((i << value.getWidth).toDouble / slices))
}