4 files changed, 40 insertions, 29 deletions

diff --git a/src/sim/sim_object.cc b/src/sim/sim_object.cc
index a0278dba0..d12b06b7a 100644
--- a/src/sim/sim_object.cc
+++ b/src/sim/sim_object.cc
@@ -72,7 +72,7 @@ SimObject::SimObject(Params *p)
 
     doRecordEvent = !Stats::event_ignore.match(name());
     simObjectList.push_back(this);
-    state = Atomic;
+    state = Running;
 }
 
 //
@@ -88,7 +88,7 @@ SimObject::SimObject(const string &_name)
 
     doRecordEvent = !Stats::event_ignore.match(name());
     simObjectList.push_back(this);
-    state = Atomic;
+    state = Running;
 }
 
 void
@@ -269,38 +269,23 @@ SimObject::recordEvent(const std::string &stat)
         Stats::recordEvent(stat);
 }
 
-bool
+unsigned int
 SimObject::drain(Event *drain_event)
 {
-    if (state != DrainedAtomic && state != Atomic) {
-        panic("Must implement your own drain function if it is to be used "
-              "in timing mode!");
-    }
-    state = DrainedAtomic;
-    return true;
+    state = Drained;
+    return 0;
 }
 
 void
 SimObject::resume()
 {
-    if (state == DrainedAtomic) {
-        state = Atomic;
-    } else if (state == DrainedTiming) {
-        state = Timing;
-    }
+    state = Running;
 }
 
 void
 SimObject::setMemoryMode(State new_mode)
 {
-    assert(new_mode == Timing || new_mode == Atomic);
-    if (state == DrainedAtomic && new_mode == Timing) {
-        state = DrainedTiming;
-    } else if (state == DrainedTiming && new_mode == Atomic) {
-        state = DrainedAtomic;
-    } else {
-        state = new_mode;
-    }
+    panic("setMemoryMode() should only be called on systems");
 }
 
 void
diff --git a/src/sim/sim_object.hh b/src/sim/sim_object.hh
index 7ecc00958..38f2bdd23 100644
--- a/src/sim/sim_object.hh
+++ b/src/sim/sim_object.hh
@@ -60,16 +60,15 @@ class SimObject : public Serializable, protected StartupCallback
     };
 
     enum State {
-        Atomic,
-        Timing,
+        Running,
         Draining,
-        DrainedAtomic,
-        DrainedTiming
+        Drained
     };
+  private:
+    State state;
 
   protected:
     Params *_params;
-    State state;
 
     void changeState(State new_state) { state = new_state; }
 
@@ -116,8 +115,10 @@ class SimObject : public Serializable, protected StartupCallback
 
     // Methods to drain objects in order to take checkpoints
     // Or switch from timing -> atomic memory model
-    // Drain returns false if the SimObject cannot drain immediately.
-    virtual bool drain(Event *drain_event);
+    // Drain returns 0 if the simobject can drain immediately or
+    // the number of times the drain_event's process function will be called
+    // before the object will be done draining. Normally this should be 1
+    virtual unsigned int drain(Event *drain_event);
     virtual void resume();
     virtual void setMemoryMode(State new_mode);
     virtual void switchOut();
diff --git a/src/sim/system.cc b/src/sim/system.cc
index 89e7b8542..2780d0fda 100644
--- a/src/sim/system.cc
+++ b/src/sim/system.cc
@@ -143,6 +143,14 @@ int rgdb_wait = -1;
 
 #endif // FULL_SYSTEM
 
+
+void
+System::setMemoryMode(MemoryMode mode)
+{
+    assert(getState() == Drained);
+    memoryMode = mode;
+}
+
 int
 System::registerThreadContext(ThreadContext *tc, int id)
 {
diff --git a/src/sim/system.hh b/src/sim/system.hh
index 059dc92dc..77777aed4 100644
--- a/src/sim/system.hh
+++ b/src/sim/system.hh
@@ -61,6 +61,21 @@ class RemoteGDB;
 class System : public SimObject
 {
   public:
+    enum MemoryMode {
+        Invalid=0,
+        Atomic,
+        Timing
+    };
+
+
+    MemoryMode getMemoryMode() { assert(memoryMode); return memoryMode; }
+
+    /** Change the memory mode of the system. This should only be called by the
+     * python!!
+     * @param mode Mode to change to (atomic/timing)
+     */
+    void setMemoryMode(MemoryMode mode);
+
     PhysicalMemory *physmem;
     PCEventQueue pcEventQueue;
 
@@ -108,6 +123,8 @@ class System : public SimObject
 
   protected:
 
+    MemoryMode memoryMode;
+
 #if FULL_SYSTEM
     /**
      * Fix up an address used to match PCs for hooking simulator