add multi-width FIFO
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770f2742de
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5241ee6442
@ -219,3 +219,71 @@ class DecoupledHelper(val rvs: Seq[Bool]) {
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(rvs.filter(_ ne exclude) ++ includes).reduce(_ && _)
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}
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}
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class MultiWidthFifo(inW: Int, outW: Int, n: Int) extends Module {
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val io = new Bundle {
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val in = Decoupled(Bits(width = inW)).flip
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val out = Decoupled(Bits(width = outW))
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}
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if (inW == outW) {
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io.out <> Queue(io.in, n)
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} else if (inW > outW) {
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val nBeats = inW / outW
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require(inW % outW == 0, s"MultiWidthFifo: in: $inW not divisible by out: $outW")
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require(n % nBeats == 0, s"Cannot store $n output words when output beats is $nBeats")
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val wdata = Reg(Vec(n / nBeats, Bits(width = inW)))
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val rdata = Vec(wdata.flatMap { indat =>
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(0 until nBeats).map(i => indat(outW * (i + 1) - 1, outW * i)) })
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val head = Reg(init = UInt(0, log2Up(n / nBeats)))
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val tail = Reg(init = UInt(0, log2Up(n)))
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val size = Reg(init = UInt(0, log2Up(n + 1)))
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when (io.in.fire()) {
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wdata(head) := io.in.bits
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head := head + UInt(1)
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}
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when (io.out.fire()) { tail := tail + UInt(1) }
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size := MuxCase(size, Seq(
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(io.in.fire() && io.out.fire()) -> (size + UInt(nBeats - 1)),
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io.in.fire() -> (size + UInt(nBeats)),
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io.out.fire() -> (size - UInt(1))))
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io.out.valid := size > UInt(0)
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io.out.bits := rdata(tail)
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io.in.ready := size < UInt(n)
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} else {
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val nBeats = outW / inW
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require(outW % inW == 0, s"MultiWidthFifo: out: $outW not divisible by in: $inW")
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val wdata = Reg(Vec(n * nBeats, Bits(width = inW)))
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val rdata = Vec.tabulate(n) { i =>
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Cat(wdata.slice(i * nBeats, (i + 1) * nBeats).reverse)}
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val head = Reg(init = UInt(0, log2Up(n * nBeats)))
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val tail = Reg(init = UInt(0, log2Up(n)))
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val size = Reg(init = UInt(0, log2Up(n * nBeats + 1)))
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when (io.in.fire()) {
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wdata(head) := io.in.bits
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head := head + UInt(1)
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}
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when (io.out.fire()) { tail := tail + UInt(1) }
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size := MuxCase(size, Seq(
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(io.in.fire() && io.out.fire()) -> (size - UInt(nBeats - 1)),
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io.in.fire() -> (size + UInt(1)),
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io.out.fire() -> (size - UInt(nBeats))))
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io.out.valid := size >= UInt(nBeats)
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io.out.bits := rdata(tail)
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io.in.ready := size < UInt(n * nBeats)
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}
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}
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