O3: Handle loads when the destination is the PC.

For loads that PC is the destination, check if the load
was mispredicted again when the value being loaded returns from memory

1 files changed, 42 insertions, 0 deletions

diff --git a/src/cpu/o3/iew_impl.hh b/src/cpu/o3/iew_impl.hh
index 751a26afd..b53b03fe0 100644
--- a/src/cpu/o3/iew_impl.hh
+++ b/src/cpu/o3/iew_impl.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2010 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2004-2006 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -1585,3 +1597,33 @@ DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst)
         }
     }
 }
+
+template <class Impl>
+void
+DefaultIEW<Impl>::checkMisprediction(DynInstPtr &inst)
+{
+    ThreadID tid = inst->threadNumber;
+
+    if (!fetchRedirect[tid] ||
+        toCommit->squashedSeqNum[tid] > inst->seqNum) {
+
+        if (inst->mispredicted()) {
+            fetchRedirect[tid] = true;
+
+            DPRINTF(IEW, "Execute: Branch mispredict detected.\n");
+            DPRINTF(IEW, "Predicted target was PC:%#x, NPC:%#x.\n",
+                    inst->readPredPC(), inst->readPredNPC());
+            DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x,"
+                    " NPC: %#x.\n", inst->readNextPC(),
+                    inst->readNextNPC());
+            // If incorrect, then signal the ROB that it must be squashed.
+            squashDueToBranch(inst, tid);
+
+            if (inst->readPredTaken()) {
+                predictedTakenIncorrect++;
+            } else {
+                predictedNotTakenIncorrect++;
+            }
+        }
+    }
+}