From ed8cc4a1cf1bfc5bc8c746726672df8330c8eb2f Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@eecs.berkeley.edu>
Date: Thu, 4 Oct 2012 09:05:14 -0700
Subject: [PATCH] eliminate D$ probe->WB critical path

---
 rocket/src/main/scala/nbdcache.scala | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/rocket/src/main/scala/nbdcache.scala b/rocket/src/main/scala/nbdcache.scala
index 951d6adc..a3402dcb 100644
--- a/rocket/src/main/scala/nbdcache.scala
+++ b/rocket/src/main/scala/nbdcache.scala
@@ -238,7 +238,7 @@ class MSHR(id: Int, co: CoherencePolicy) extends Component {
     when (abort) { state := s_wb_req }
   }
   when (state === s_wb_req) {
-    when (io.probe_writeback.valid && idx_match) { state := s_refill_req }
+    when (io.probe_writeback.valid && io.probe_writeback.bits && idx_match) { state := s_refill_req }
     .elsewhen (io.wb_req.ready) { state := s_wb_resp }
   }
 
@@ -366,7 +366,8 @@ class MSHRFile(co: CoherencePolicy) extends Component {
     mshr.io.wb_req <> wb_req_arb.io.in(i)
     mshr.io.replay <> replay_arb.io.in(i)
     mshr.io.probe_refill.valid := io.probe.valid && tag_match
-    mshr.io.probe_writeback.valid := io.probe.valid && wb_probe_match
+    mshr.io.probe_writeback.valid := io.probe.valid
+    mshr.io.probe_writeback.bits := wb_probe_match
 
     mshr.io.mem_abort <> io.mem_abort
     mshr.io.mem_rep <> io.mem_rep