From c6944e320cfa86d3f2ce628457aff4bc431e7189 Mon Sep 17 00:00:00 2001
From: Gabe Black <gblack@eecs.umich.edu>
Date: Sat, 16 Dec 2006 07:35:56 -0500
Subject: Add in capability to return to unblocking after a squash. This is
 needed because if you don't squash -all- the instructions, you need to keep
 clearing out whatever is left in the skid buffer.

--HG--
extra : convert_revision : 7308eda27f4366348cf5fce71ddfa4b217bc172d
---
 src/cpu/o3/rename.hh      |  4 ++++
 src/cpu/o3/rename_impl.hh | 44 ++++++++++++++++++++++++++++++++++++--------
 2 files changed, 40 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/cpu/o3/rename.hh b/src/cpu/o3/rename.hh
index 1ede6f355..6b4628f92 100644
--- a/src/cpu/o3/rename.hh
+++ b/src/cpu/o3/rename.hh
@@ -415,6 +415,10 @@ class DefaultRename
      * after squashing. */
     bool resumeSerialize;
 
+    /** Whether or not rename needs to resume clearing out the skidbuffer
+     * after squashing. */
+    bool resumeUnblocking;
+
     /** The number of threads active in rename. */
     unsigned numThreads;
 
diff --git a/src/cpu/o3/rename_impl.hh b/src/cpu/o3/rename_impl.hh
index 0c211b183..7a7234965 100644
--- a/src/cpu/o3/rename_impl.hh
+++ b/src/cpu/o3/rename_impl.hh
@@ -44,6 +44,7 @@ DefaultRename<Impl>::DefaultRename(Params *params)
       renameWidth(params->renameWidth),
       commitWidth(params->commitWidth),
       resumeSerialize(false),
+      resumeUnblocking(false),
       numThreads(params->numberOfThreads),
       maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs)
 {
@@ -405,6 +406,9 @@ DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, unsigned tid)
         }
         slist_it++;
     }
+    resumeUnblocking = (skidBuffer[tid].size() != 0);
+    DPRINTF(Rename, "Resume unblocking set to %s\n",
+            resumeUnblocking ? "true" : "false");
 #else
     skidBuffer[tid].clear();
 #endif
@@ -496,6 +500,12 @@ DefaultRename<Impl>::rename(bool &status_change, unsigned tid)
             block(tid);
             toDecode->renameUnblock[tid] = false;
         }
+    } else if (renameStatus[tid] == Unblocking) {
+        if (resumeUnblocking) {
+            block(tid);
+            resumeUnblocking = false;
+            toDecode->renameUnblock[tid] = false;
+        }
     }
 
     if (renameStatus[tid] == Running ||
@@ -761,7 +771,17 @@ DefaultRename<Impl>::skidInsert(unsigned tid)
     }
 
     if (skidBuffer[tid].size() > skidBufferMax)
+    {
+        typename InstQueue::iterator it;
+        warn("Skidbuffer contents:\n");
+        for(it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++)
+        {
+            warn("[tid:%u]: %s [sn:%i].\n", tid,
+                    (*it)->staticInst->disassemble(inst->readPC()),
+                    (*it)->seqNum);
+        }
         panic("Skidbuffer Exceeded Max Size");
+    }
 }
 
 template <class Impl>
@@ -848,7 +868,10 @@ DefaultRename<Impl>::block(unsigned tid)
     // Only signal backwards to block if the previous stages do not think
     // rename is already blocked.
     if (renameStatus[tid] != Blocked) {
-        if (renameStatus[tid] != Unblocking) {
+        // If resumeUnblocking is set, we unblocked during the squash,
+        // but now we're have unblocking status. We need to tell earlier
+        // stages to block.
+        if (resumeUnblocking || renameStatus[tid] != Unblocking) {
             toDecode->renameBlock[tid] = true;
             toDecode->renameUnblock[tid] = false;
             wroteToTimeBuffer = true;
@@ -1264,18 +1287,23 @@ DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid)
     if (renameStatus[tid] == Squashing) {
         // Switch status to running if rename isn't being told to block or
         // squash this cycle.
-        if (!resumeSerialize) {
-            DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
-                    tid);
-
-            renameStatus[tid] = Running;
-            return false;
-        } else {
+        if (resumeSerialize) {
             DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n",
                     tid);
 
             renameStatus[tid] = SerializeStall;
             return true;
+        } else if (resumeUnblocking) {
+            DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n",
+                    tid);
+            renameStatus[tid] = Unblocking;
+            return true;
+        } else {
+            DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
+                    tid);
+
+            renameStatus[tid] = Running;
+            return false;
         }
     }
 
-- 
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