From 37b9966eb466b1655f0d4e604bafa729a3aaea6a Mon Sep 17 00:00:00 2001
From: Gabe Black <gblack@eecs.umich.edu>
Date: Sat, 16 Dec 2006 07:32:06 -0500
Subject: Made branch delay slots get squashed, and passed back an NPC and NNPC
 to start fetching from.

--HG--
extra : convert_revision : a2e4845fedf113b5a2fd92d3d28ce5b006278103
---
 src/cpu/o3/iew_impl.hh | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

(limited to 'src/cpu/o3/iew_impl.hh')

diff --git a/src/cpu/o3/iew_impl.hh b/src/cpu/o3/iew_impl.hh
index 85db68576..24c8484b4 100644
--- a/src/cpu/o3/iew_impl.hh
+++ b/src/cpu/o3/iew_impl.hh
@@ -481,25 +481,28 @@ DefaultIEW<Impl>::squashDueToBranch(DynInstPtr &inst, unsigned tid)
     toCommit->branchMispredict[tid] = true;
 
 #if ISA_HAS_DELAY_SLOT
+    int instSize = sizeof(TheISA::MachInst);
     bool branch_taken =
-        (inst->readNextNPC() != (inst->readPC() + 2 * sizeof(TheISA::MachInst)) &&
-         inst->readNextNPC() != (inst->readPC() + 3 * sizeof(TheISA::MachInst)));
+        !(inst->readNextPC() + instSize == inst->readNextNPC() &&
+          (inst->readNextPC() == inst->readPC() + instSize ||
+           inst->readNextPC() == inst->readPC() + 2 * instSize));
     DPRINTF(Sparc, "Branch taken = %s [sn:%i]\n",
             branch_taken ? "true": "false", inst->seqNum);
 
     toCommit->branchTaken[tid] = branch_taken;
 
-    bool squashDelaySlot =
-        (inst->readNextPC() != inst->readPC() + sizeof(TheISA::MachInst));
+    bool squashDelaySlot = true;
+//	(inst->readNextPC() != inst->readPC() + sizeof(TheISA::MachInst));
     DPRINTF(Sparc, "Squash delay slot = %s [sn:%i]\n",
             squashDelaySlot ? "true": "false", inst->seqNum);
     toCommit->squashDelaySlot[tid] = squashDelaySlot;
     //If we're squashing the delay slot, we need to pick back up at NextPC.
     //Otherwise, NextPC isn't being squashed, so we should pick back up at
     //NextNPC.
-    if (squashDelaySlot)
+    if (squashDelaySlot) {
         toCommit->nextPC[tid] = inst->readNextPC();
-    else
+        toCommit->nextNPC[tid] = inst->readNextNPC();
+    } else
         toCommit->nextPC[tid] = inst->readNextNPC();
 #else
     toCommit->branchTaken[tid] = inst->readNextPC() !=
@@ -522,6 +525,9 @@ DefaultIEW<Impl>::squashDueToMemOrder(DynInstPtr &inst, unsigned tid)
     toCommit->squash[tid] = true;
     toCommit->squashedSeqNum[tid] = inst->seqNum;
     toCommit->nextPC[tid] = inst->readNextPC();
+#if ISA_HAS_DELAY_SLOT
+    toCommit->nextNPC[tid] = inst->readNextNPC();
+#endif
 
     toCommit->includeSquashInst[tid] = false;
 
@@ -538,6 +544,9 @@ DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid)
     toCommit->squash[tid] = true;
     toCommit->squashedSeqNum[tid] = inst->seqNum;
     toCommit->nextPC[tid] = inst->readPC();
+#if ISA_HAS_DELAY_SLOT
+    toCommit->nextNPC[tid] = inst->readNextNPC();
+#endif
 
     // Must include the broadcasted SN in the squash.
     toCommit->includeSquashInst[tid] = true;
@@ -1342,6 +1351,7 @@ DefaultIEW<Impl>::executeInsts()
                 fetchRedirect[tid] = true;
 
                 DPRINTF(IEW, "Execute: Branch mispredict detected.\n");
+                DPRINTF(IEW, "Predicted target was %#x.\n", inst->predPC);
 #if ISA_HAS_DELAY_SLOT
                 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n",
                         inst->nextNPC);
@@ -1352,7 +1362,7 @@ DefaultIEW<Impl>::executeInsts()
                 // If incorrect, then signal the ROB that it must be squashed.
                 squashDueToBranch(inst, tid);
 
-                if (inst->predTaken()) {
+                if (inst->readPredTaken()) {
                     predictedTakenIncorrect++;
                 } else {
                     predictedNotTakenIncorrect++;
-- 
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