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

1 files changed, 19 insertions, 6 deletions

diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh
index bd0451601..cf3747601 100644
--- a/src/cpu/o3/cpu.hh
+++ b/src/cpu/o3/cpu.hh
@@ -57,6 +57,8 @@ class Checker;
 class ThreadContext;
 template <class>
 class O3ThreadContext;
+
+class Checkpoint;
 class MemObject;
 class Process;
 
@@ -109,6 +111,7 @@ class FullO3CPU : public BaseO3CPU
         Idle,
         Halted,
         Blocked,
+        Drained,
         SwitchedOut
     };
 
@@ -270,14 +273,21 @@ class FullO3CPU : public BaseO3CPU
      */
     virtual void syscall(int tid) { panic("Unimplemented!"); }
 
-    /** Switches out this CPU. */
-    void switchOut();
+    /** Starts draining the CPU's pipeline of all instructions in
+     * order to stop all memory accesses. */
+    virtual bool drain(Event *drain_event);
+
+    /** Resumes execution after a drain. */
+    virtual void resume();
 
     /** Signals to this CPU that a stage has completed switching out. */
-    void signalSwitched();
+    void signalDrained();
+
+    /** Switches out this CPU. */
+    virtual void switchOut();
 
     /** Takes over from another CPU. */
-    void takeOverFrom(BaseCPU *oldCPU);
+    virtual void takeOverFrom(BaseCPU *oldCPU);
 
     /** Get the current instruction sequence number, and increment it. */
     InstSeqNum getAndIncrementInstSeq()
@@ -550,8 +560,11 @@ class FullO3CPU : public BaseO3CPU
     /** Pointer to memory. */
     MemObject *mem;
 
-    /** Counter of how many stages have completed switching out. */
-    int switchCount;
+    /** Event to call process() on once draining has completed. */
+    Event *drainEvent;
+
+    /** Counter of how many stages have completed draining. */
+    int drainCount;
 
     /** Pointers to all of the threads in the CPU. */
     std::vector<Thread *> thread;