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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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94
src/main/scala/tile/FPU.scala
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@ -232,10 +232,11 @@ object FType {
trait HasFPUParameters { trait HasFPUParameters {
val fLen: Int val fLen: Int
val xLen: Int
val minXLen = 32 val minXLen = 32
val (sExpWidth, sSigWidth) = (FType.S.exp, FType.S.sig) val nIntTypes = log2Ceil(xLen/minXLen) + 1
val (dExpWidth, dSigWidth) = (FType.D.exp, FType.D.sig)
val floatTypes = FType.all.filter(_.ieeeWidth <= fLen) val floatTypes = FType.all.filter(_.ieeeWidth <= fLen)
val minType = floatTypes.head
val maxType = floatTypes.last val maxType = floatTypes.last
def prevType(t: FType) = floatTypes(typeTag(t) - 1) def prevType(t: FType) = floatTypes(typeTag(t) - 1)
val maxExpWidth = maxType.exp val maxExpWidth = maxType.exp
@ -379,11 +380,10 @@ class FPToInt(implicit p: Parameters) extends FPUModule()(p) {
dcmp.io.b := in.in2 dcmp.io.b := in.in2
dcmp.io.signaling := !in.rm(1) dcmp.io.signaling := !in.rm(1)
val tag = !in.singleOut val tag = !in.singleOut // TODO typeTag
val store = ieee(in.in1) val store = ieee(in.in1)
val toint = Wire(init = store) val toint = Wire(init = store)
val intType = Wire(init = tag) 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.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.toint := ((0 until nIntTypes).map(i => toint((minXLen << i) - 1, 0).sextTo(xLen)): Seq[UInt])(intType)
io.out.bits.exc := Bits(0) 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 in = Pipe(io.in)
val tag = !in.bits.singleIn // TODO typeTag
val mux = Wire(new FPResult) val mux = Wire(new FPResult)
mux.exc := Bits(0) mux.exc := Bits(0)
mux.data := recode(in.bits.in1, !in.bits.singleIn) mux.data := recode(in.bits.in1, !in.bits.singleIn)
val intValue = { val intValue = {
val n = log2Ceil(xLen/minXLen) + 1
val res = Wire(init = in.bits.in1.asSInt) 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) 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) 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 when (in.bits.wflags) { // fcvt
val l2s = Module(new hardfloat.INToRecFN(xLen, sExpWidth, sSigWidth)) // could be improved for RVD/RVQ with a single variable-position rounding
l2s.io.signedIn := ~in.bits.typ(0) // unit, rather than N fixed-position ones
l2s.io.in := intValue val i2fResults = for (t <- floatTypes) yield {
l2s.io.roundingMode := in.bits.rm val i2f = Module(new hardfloat.INToRecFN(xLen, t.exp, t.sig))
l2s.io.detectTininess := hardfloat.consts.tininess_afterRounding i2f.io.signedIn := ~in.bits.typ(0)
mux.data := sanitizeNaN(l2s.io.out, FType.S) i2f.io.in := intValue
mux.exc := l2s.io.exceptionFlags i2f.io.roundingMode := in.bits.rm
i2f.io.detectTininess := hardfloat.consts.tininess_afterRounding
(sanitizeNaN(i2f.io.out, t), i2f.io.exceptionFlags)
}
fLen match { val (data, exc) = i2fResults.unzip
case 32 => val dataPadded = data.init.map(d => Cat(data.last >> d.getWidth, d)) :+ data.last
case 64 => mux.data := dataPadded(tag)
val l2d = Module(new hardfloat.INToRecFN(xLen, dExpWidth, dSigWidth)) mux.exc := exc(tag)
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
}
}
} }
io.out <> Pipe(in.valid, mux, latency-1) io.out <> Pipe(in.valid, mux, latency-1)
@ -511,32 +504,33 @@ 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)) 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) val mux = Wire(init = fsgnjMux)
fLen match { for (t <- floatTypes.init) {
case 32 => when (outTag === typeTag(t)) {
case 64 => mux.data := Cat(fsgnjMux.data >> t.recodedWidth, maxType.unsafeConvert(fsgnjMux.data, t))
val fsgnjSingle = maxType.unsafeConvert(fsgnjMux.data, FType.S) }
when (in.bits.singleOut) { mux.data := Cat(fsgnjMux.data >> fsgnjSingle.getWidth, fsgnjSingle) } }
when (in.bits.wflags && !in.bits.ren2) { // fcvt when (in.bits.wflags && !in.bits.ren2) { // fcvt
val d2s = Module(new hardfloat.RecFNToRecFN(dExpWidth, dSigWidth, sExpWidth, sSigWidth)) if (floatTypes.size > 1) {
d2s.io.in := in.bits.in1 // widening conversions simply canonicalize NaN operands
d2s.io.roundingMode := in.bits.rm val widened = Mux(maxType.isNaN(in.bits.in1), maxType.qNaN, in.bits.in1)
d2s.io.detectTininess := hardfloat.consts.tininess_afterRounding fsgnjMux.data := widened
val d2sOut = sanitizeNaN(d2s.io.out, FType.S) fsgnjMux.exc := maxType.isSNaN(in.bits.in1) << 4
val s2d = Module(new hardfloat.RecFNToRecFN(sExpWidth, sSigWidth, dExpWidth, dSigWidth)) // narrowing conversions require rounding (for RVQ, this could be
s2d.io.in := maxType.unsafeConvert(in.bits.in1, FType.S) // optimized to use a single variable-position rounding unit, rather
s2d.io.roundingMode := in.bits.rm // than two fixed-position ones)
s2d.io.detectTininess := hardfloat.consts.tininess_afterRounding for (outType <- floatTypes.init) when (outTag === typeTag(outType) && (typeTag(outType) == 0 || outTag < inTag)) {
val s2dOut = sanitizeNaN(s2d.io.out, FType.D) val narrower = Module(new hardfloat.RecFNToRecFN(maxType.exp, maxType.sig, outType.exp, outType.sig))
narrower.io.in := in.bits.in1
when (in.bits.singleOut) { narrower.io.roundingMode := in.bits.rm
mux.data := Cat(s2dOut >> d2sOut.getWidth, d2sOut) narrower.io.detectTininess := hardfloat.consts.tininess_afterRounding
mux.exc := d2s.io.exceptionFlags val narrowed = sanitizeNaN(narrower.io.out, outType)
}.otherwise { mux.data := Cat(fsgnjMux.data >> narrowed.getWidth, narrowed)
mux.data := s2dOut mux.exc := narrower.io.exceptionFlags
mux.exc := s2d.io.exceptionFlags
} }
} }
} }