systemc: Handle suspended processes and handle sensitivity overload.

This change keeps track of whether a process would have become ready
but was suspended so that it can become ready when the process is
resumed.

Also, this makes a process ignore its static sensitivity while a
dynamic sensitivity is in place.

Change-Id: If3f6c62f370051e574f81bf227746db8c43527e2
Reviewed-on: https://gem5-review.googlesource.com/11715
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/process.cc

@@ -36,14 +36,6 @@
 namespace sc_gem5
 {
 
-void
-Sensitivity::satisfy()
-{
-    warn_once("Ignoring suspended status for now.\n");
-    process->setDynamic(nullptr);
-    scheduler.ready(process);
-}
-
 SensitivityTimeout::SensitivityTimeout(Process *p, ::sc_core::sc_time t) :
     Sensitivity(p), timeoutEvent(this), timeout(t)
 {
@@ -88,7 +80,7 @@ SensitivityEventAndList::notifyWork(Event *e)
     e->delSensitivity(this);
     count++;
     if (count == list->events.size())
-        satisfy();
+        process->satisfySensitivity(this);
 }
 
 SensitivityEventOrList::SensitivityEventOrList(
@@ -150,7 +142,7 @@ Process::suspend(bool inc_kids)
 
     if (!_suspended) {
         _suspended = true;
-        //TODO Suspend this process.
+        _suspendedReady = false;
     }
 
     if (procKind() != ::sc_core::SC_METHOD_PROC_ &&
@@ -167,7 +159,9 @@ Process::resume(bool inc_kids)
 
     if (_suspended) {
         _suspended = false;
-        //TODO Resume this process.
+        if (_suspendedReady)
+            ready();
+        _suspendedReady = false;
     }
 }
 
@@ -309,6 +303,26 @@ Process::setDynamic(Sensitivity *s)
     dynamicSensitivity = s;
 }
 
+void
+Process::satisfySensitivity(Sensitivity *s)
+{
+    // If there's a dynamic sensitivity and this wasn't it, ignore.
+    if (dynamicSensitivity && dynamicSensitivity != s)
+        return;
+
+    setDynamic(nullptr);
+    ready();
+}
+
+void
+Process::ready()
+{
+    if (suspended())
+        _suspendedReady = true;
+    else
+        scheduler.ready(this);
+}
+
 Process::Process(const char *name, ProcessFuncWrapper *func, bool _dynamic) :
     ::sc_core::sc_object(name), excWrapper(nullptr), func(func),
     _running(false), _dynamic(_dynamic), _isUnwinding(false),