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AsyncQueue: make it clear that the SyncChain is not Gray specific

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This commit is contained in:
Wesley W. Terpstra 2016-10-08 20:31:43 -07:00
parent 52b8121e68
commit e7f8a7e9ea
1 changed files with 5 additions and 5 deletions
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10
src/main/scala/util/AsyncQueue.scala
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@ -12,7 +12,7 @@ object GrayCounter {
}
}
object AsyncGrayCounter {
object UIntSyncChain {
def apply(in: UInt, sync: Int, name: String = "gray"): UInt = {
val syncv = List.tabulate(sync) { i =>
Module (new AsyncResetRegVec(w = in.getWidth, 0)).suggestName(s"${name}_sync_${i}")
@ -43,11 +43,11 @@ class AsyncQueueSource[T <: Data](gen: T, depth: Int, sync: Int) extends Module
// extend the sink reset to a full cycle (assertion latency <= 1 cycle)
val catch_reset_n = AsyncResetReg(Bool(true), clock, !io.sink_reset_n, "catch_sink_reset_n")
// reset_n has a 1 cycle shorter path to ready than ridx does
val sink_reset_n = AsyncGrayCounter(catch_reset_n.asUInt, sync, "sink_reset_n")(0)
val sink_reset_n = UIntSyncChain(catch_reset_n.asUInt, sync, "sink_reset_n")(0)
val mem = Reg(Vec(depth, gen)) //This does NOT need to be asynchronously reset.
val widx = GrayCounter(bits+1, io.enq.fire(), !sink_reset_n, "widx_bin")
val ridx = AsyncGrayCounter(io.ridx, sync, "ridx_gray")
val ridx = UIntSyncChain(io.ridx, sync, "ridx_gray")
val ready = widx =/= (ridx ^ UInt(depth | depth >> 1))
val index = if (depth == 1) UInt(0) else io.widx(bits-1, 0) ^ (io.widx(bits, bits) << (bits-1))
@ -81,10 +81,10 @@ class AsyncQueueSink[T <: Data](gen: T, depth: Int, sync: Int) extends Module {
// extend the source reset to a full cycle (assertion latency <= 1 cycle)
val catch_reset_n = AsyncResetReg(Bool(true), clock, !io.source_reset_n, "catch_source_reset_n")
// reset_n has a 1 cycle shorter path to valid than widx does
val source_reset_n = AsyncGrayCounter(catch_reset_n.asUInt, sync, "source_reset_n")(0)
val source_reset_n = UIntSyncChain(catch_reset_n.asUInt, sync, "source_reset_n")(0)
val ridx = GrayCounter(bits+1, io.deq.fire(), !source_reset_n, "ridx_bin")
val widx = AsyncGrayCounter(io.widx, sync, "widx_gray")
val widx = UIntSyncChain(io.widx, sync, "widx_gray")
val valid = ridx =/= widx
// The mux is safe because timing analysis ensures ridx has reached the register