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tilelink2: more efficient one-hot circuits

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This commit is contained in:
Wesley W. Terpstra 2016-09-02 11:52:47 -07:00
parent 3d84795641
commit ecc3c2a4b2
1 changed files with 5 additions and 4 deletions
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9
uncore/src/main/scala/tilelink2/Edges.scala
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@ -12,8 +12,9 @@ class TLEdge(
{ {
def isAligned(address: UInt, lgSize: UInt) = def isAligned(address: UInt, lgSize: UInt) =
if (maxLgSize == 0) Bool(true) else { if (maxLgSize == 0) Bool(true) else {
val mask = Vec.tabulate(maxLgSize) { UInt(_) < lgSize } val ones = UInt((1 << maxLgSize) - 1)
(address & Cat(mask.reverse)) === UInt(0) val mask = (ones << lgSize)(maxLgSize*2-1, maxLgSize)
(address & mask) === UInt(0)
} }
// This gets used everywhere, so make the smallest circuit possible ... // This gets used everywhere, so make the smallest circuit possible ...
@ -43,8 +44,8 @@ class TLEdge(
val size = bundle.size() val size = bundle.size()
val cutoff = log2Ceil(manager.beatBytes) val cutoff = log2Ceil(manager.beatBytes)
val small = size <= UInt(cutoff) val small = size <= UInt(cutoff)
val decode = Vec.tabulate (1+maxLgSize-cutoff) { i => UInt(i + cutoff) === size } val decode = UIntToOH(size, maxLgSize+1) >> cutoff
Mux(!hasData || small, UInt(1), Cat(decode.reverse)) Mux(!hasData || small, UInt(1), decode)
} }
} }