riscv/rocket-chip
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fix SRAM semantics bug in HellaFlowQueue

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This commit is contained in:
Andrew Waterman 2013-01-29 21:16:20 -08:00
parent 60bd3a6413
commit 66eb3720a4
1 changed files with 6 additions and 5 deletions
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11
rocket/src/main/scala/util.scala
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@ -91,21 +91,22 @@ class HellaFlowQueue[T <: Data](val entries: Int)(data: => T) extends Component
val ptr_match = enq_ptr === deq_ptr val ptr_match = enq_ptr === deq_ptr
val empty = ptr_match && !maybe_full val empty = ptr_match && !maybe_full
val full = ptr_match && maybe_full val full = ptr_match && maybe_full
val atLeastTwo = full || enq_ptr - deq_ptr >= UFix(2)
do_flow := empty && io.deq.ready do_flow := empty && io.deq.ready
val ram = Mem(entries, seqRead = true){data} val ram = Mem(entries, seqRead = true){Bits(width = data.getWidth)}
val ram_out = Reg{data} val ram_out = Reg{Bits(width = data.getWidth)}
val ram_out_valid = Reg{Bool()} val ram_out_valid = Reg{Bool()}
ram_out_valid := Bool(false) ram_out_valid := Bool(false)
when (io.deq.ready && !empty) { when (io.deq.ready && (atLeastTwo || !io.deq.valid && !empty)) {
ram_out_valid := Bool(true) ram_out_valid := Bool(true)
ram_out := ram(Mux(io.deq.valid, deq_ptr + UFix(1), deq_ptr)) ram_out := ram(Mux(io.deq.valid, deq_ptr + UFix(1), deq_ptr))
} }
when (do_enq) { ram(enq_ptr) := io.enq.bits } when (do_enq) { ram(enq_ptr) := io.enq.bits.toBits }
io.deq.valid := Mux(empty, io.enq.valid, ram_out_valid) io.deq.valid := Mux(empty, io.enq.valid, ram_out_valid)
io.enq.ready := !full io.enq.ready := !full
io.deq.bits := Mux(empty, io.enq.bits, ram_out) io.deq.bits := Mux(empty, io.enq.bits, data.fromBits(ram_out))
} }
class HellaQueue[T <: Data](val entries: Int)(data: => T) extends Component class HellaQueue[T <: Data](val entries: Int)(data: => T) extends Component