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Improve code quality in FP->FP and Int->FP units

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This commit is contained in:
Andrew Waterman 2017-05-31 14:53:46 -07:00 committed by Wesley W. Terpstra
parent 84c4ae775f
commit 7504b47bbe
1 changed files with 46 additions and 52 deletions
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98
src/main/scala/tile/FPU.scala
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@ -232,10 +232,11 @@ object FType {
trait HasFPUParameters {
val fLen: Int
val xLen: Int
val minXLen = 32
val (sExpWidth, sSigWidth) = (FType.S.exp, FType.S.sig)
val (dExpWidth, dSigWidth) = (FType.D.exp, FType.D.sig)
val nIntTypes = log2Ceil(xLen/minXLen) + 1
val floatTypes = FType.all.filter(_.ieeeWidth <= fLen)
val minType = floatTypes.head
val maxType = floatTypes.last
def prevType(t: FType) = floatTypes(typeTag(t) - 1)
val maxExpWidth = maxType.exp
@ -379,11 +380,10 @@ class FPToInt(implicit p: Parameters) extends FPUModule()(p) {
dcmp.io.b := in.in2
dcmp.io.signaling := !in.rm(1)
val tag = !in.singleOut
val tag = !in.singleOut // TODO typeTag
val store = ieee(in.in1)
val toint = Wire(init = store)
val intType = Wire(init = tag)
val nIntTypes = log2Ceil(xLen/minXLen) + 1
io.out.bits.store := ((0 until nIntTypes).map(i => Fill(1 << (nIntTypes - i - 1), store((minXLen << i) - 1, 0))): Seq[UInt])(tag)
io.out.bits.toint := ((0 until nIntTypes).map(i => toint((minXLen << i) - 1, 0).sextTo(xLen)): Seq[UInt])(intType)
io.out.bits.exc := Bits(0)
@ -440,17 +440,17 @@ class IntToFP(val latency: Int)(implicit p: Parameters) extends FPUModule()(p) {
}
val in = Pipe(io.in)
val tag = !in.bits.singleIn // TODO typeTag
val mux = Wire(new FPResult)
mux.exc := Bits(0)
mux.data := recode(in.bits.in1, !in.bits.singleIn)
val intValue = {
val n = log2Ceil(xLen/minXLen) + 1
val res = Wire(init = in.bits.in1.asSInt)
for (i <- 0 until n-1) {
for (i <- 0 until nIntTypes-1) {
val smallInt = in.bits.in1((minXLen << i) - 1, 0)
when (in.bits.typ.extract(log2Ceil(n), 1) === i) {
when (in.bits.typ.extract(log2Ceil(nIntTypes), 1) === i) {
res := Mux(in.bits.typ(0), smallInt.zext, smallInt.asSInt)
}
}
@ -458,28 +458,21 @@ class IntToFP(val latency: Int)(implicit p: Parameters) extends FPUModule()(p) {
}
when (in.bits.wflags) { // fcvt
val l2s = Module(new hardfloat.INToRecFN(xLen, sExpWidth, sSigWidth))
l2s.io.signedIn := ~in.bits.typ(0)
l2s.io.in := intValue
l2s.io.roundingMode := in.bits.rm
l2s.io.detectTininess := hardfloat.consts.tininess_afterRounding
mux.data := sanitizeNaN(l2s.io.out, FType.S)
mux.exc := l2s.io.exceptionFlags
fLen match {
case 32 =>
case 64 =>
val l2d = Module(new hardfloat.INToRecFN(xLen, dExpWidth, dSigWidth))
l2d.io.signedIn := ~in.bits.typ(0)
l2d.io.in := intValue
l2d.io.roundingMode := in.bits.rm
l2d.io.detectTininess := hardfloat.consts.tininess_afterRounding
mux.data := Cat(l2d.io.out >> l2s.io.out.getWidth, l2s.io.out)
when (!in.bits.singleIn) {
mux.data := sanitizeNaN(l2d.io.out, FType.D)
mux.exc := l2d.io.exceptionFlags
}
// could be improved for RVD/RVQ with a single variable-position rounding
// unit, rather than N fixed-position ones
val i2fResults = for (t <- floatTypes) yield {
val i2f = Module(new hardfloat.INToRecFN(xLen, t.exp, t.sig))
i2f.io.signedIn := ~in.bits.typ(0)
i2f.io.in := intValue
i2f.io.roundingMode := in.bits.rm
i2f.io.detectTininess := hardfloat.consts.tininess_afterRounding
(sanitizeNaN(i2f.io.out, t), i2f.io.exceptionFlags)
}
val (data, exc) = i2fResults.unzip
val dataPadded = data.init.map(d => Cat(data.last >> d.getWidth, d)) :+ data.last
mux.data := dataPadded(tag)
mux.exc := exc(tag)
}
io.out <> Pipe(in.valid, mux, latency-1)
@ -511,34 +504,35 @@ class FPToFP(val latency: Int)(implicit p: Parameters) extends FPUModule()(p) {
fsgnjMux.data := Mux(isNaNOut, maxType.qNaN, Mux(isLHS, in.bits.in1, in.bits.in2))
}
val inTag = !in.bits.singleIn // TODO typeTag
val outTag = !in.bits.singleOut // TODO typeTag
val mux = Wire(init = fsgnjMux)
fLen match {
case 32 =>
case 64 =>
val fsgnjSingle = maxType.unsafeConvert(fsgnjMux.data, FType.S)
when (in.bits.singleOut) { mux.data := Cat(fsgnjMux.data >> fsgnjSingle.getWidth, fsgnjSingle) }
for (t <- floatTypes.init) {
when (outTag === typeTag(t)) {
mux.data := Cat(fsgnjMux.data >> t.recodedWidth, maxType.unsafeConvert(fsgnjMux.data, t))
}
}
when (in.bits.wflags && !in.bits.ren2) { // fcvt
val d2s = Module(new hardfloat.RecFNToRecFN(dExpWidth, dSigWidth, sExpWidth, sSigWidth))
d2s.io.in := in.bits.in1
d2s.io.roundingMode := in.bits.rm
d2s.io.detectTininess := hardfloat.consts.tininess_afterRounding
val d2sOut = sanitizeNaN(d2s.io.out, FType.S)
when (in.bits.wflags && !in.bits.ren2) { // fcvt
if (floatTypes.size > 1) {
// widening conversions simply canonicalize NaN operands
val widened = Mux(maxType.isNaN(in.bits.in1), maxType.qNaN, in.bits.in1)
fsgnjMux.data := widened
fsgnjMux.exc := maxType.isSNaN(in.bits.in1) << 4
val s2d = Module(new hardfloat.RecFNToRecFN(sExpWidth, sSigWidth, dExpWidth, dSigWidth))
s2d.io.in := maxType.unsafeConvert(in.bits.in1, FType.S)
s2d.io.roundingMode := in.bits.rm
s2d.io.detectTininess := hardfloat.consts.tininess_afterRounding
val s2dOut = sanitizeNaN(s2d.io.out, FType.D)
when (in.bits.singleOut) {
mux.data := Cat(s2dOut >> d2sOut.getWidth, d2sOut)
mux.exc := d2s.io.exceptionFlags
}.otherwise {
mux.data := s2dOut
mux.exc := s2d.io.exceptionFlags
}
// narrowing conversions require rounding (for RVQ, this could be
// optimized to use a single variable-position rounding unit, rather
// than two fixed-position ones)
for (outType <- floatTypes.init) when (outTag === typeTag(outType) && (typeTag(outType) == 0 || outTag < inTag)) {
val narrower = Module(new hardfloat.RecFNToRecFN(maxType.exp, maxType.sig, outType.exp, outType.sig))
narrower.io.in := in.bits.in1
narrower.io.roundingMode := in.bits.rm
narrower.io.detectTininess := hardfloat.consts.tininess_afterRounding
val narrowed = sanitizeNaN(narrower.io.out, outType)
mux.data := Cat(fsgnjMux.data >> narrowed.getWidth, narrowed)
mux.exc := narrower.io.exceptionFlags
}
}
}
io.out <> Pipe(in.valid, mux, latency-1)