From 30c516d51cad44f62a7269a59f067ae5a1be81df Mon Sep 17 00:00:00 2001
From: Kevin Lim <ktlim@umich.edu>
Date: Thu, 6 Jul 2006 13:59:02 -0400
Subject: Support for draining, and the new method of switching out.  Now
 switching out happens after the pipeline has been drained, deferring the
 three way handshake to the normal drain mechanism.  The calls of switchOut()
 and takeOverFrom() both take action immediately.

src/cpu/o3/commit.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/rename.hh:
src/cpu/o3/rename_impl.hh:
    Support for draining, new method of switching out.

--HG--
extra : convert_revision : 05bf8b271ec85b3e2c675c3bed6c42aeba21f465
---
 src/cpu/o3/fetch_impl.hh | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

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

diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh
index 60eb76d17..500b5304e 100644
--- a/src/cpu/o3/fetch_impl.hh
+++ b/src/cpu/o3/fetch_impl.hh
@@ -109,6 +109,7 @@ DefaultFetch<Impl>::DefaultFetch(Params *params)
       numThreads(params->numberOfThreads),
       numFetchingThreads(params->smtNumFetchingThreads),
       interruptPending(false),
+      drainPending(false),
       switchedOut(false)
 {
     if (numThreads > Impl::MaxThreads)
@@ -353,7 +354,8 @@ DefaultFetch<Impl>::processCacheCompletion(PacketPtr pkt)
     // to return.
     if (fetchStatus[tid] != IcacheWaitResponse ||
         pkt->req != memReq[tid] ||
-        isSwitchedOut()) {
+        isSwitchedOut() ||
+        drainPending) {
         ++fetchIcacheSquashes;
         delete pkt->req;
         delete pkt;
@@ -384,17 +386,25 @@ DefaultFetch<Impl>::processCacheCompletion(PacketPtr pkt)
 
 template <class Impl>
 void
-DefaultFetch<Impl>::switchOut()
+DefaultFetch<Impl>::drain()
 {
-    // Fetch is ready to switch out at any time.
-    switchedOut = true;
-    cpu->signalSwitched();
+    // Fetch is ready to drain at any time.
+    cpu->signalDrained();
+    drainPending = true;
 }
 
 template <class Impl>
 void
-DefaultFetch<Impl>::doSwitchOut()
+DefaultFetch<Impl>::resume()
 {
+    drainPending = false;
+}
+
+template <class Impl>
+void
+DefaultFetch<Impl>::switchOut()
+{
+    switchedOut = true;
     // Branch predictor needs to have its state cleared.
     branchPred.switchOut();
 }
@@ -498,7 +508,7 @@ DefaultFetch<Impl>::fetchCacheLine(Addr fetch_PC, Fault &ret_fault, unsigned tid
     unsigned flags = 0;
 #endif // FULL_SYSTEM
 
-    if (cacheBlocked || (interruptPending && flags == 0) || switchedOut) {
+    if (cacheBlocked || (interruptPending && flags == 0) || drainPending) {
         // Hold off fetch from getting new instructions when:
         // Cache is blocked, or
         // while an interrupt is pending and we're not in PAL mode, or
-- 
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