systemc: Rework the init phase for the new way delta notes are handled.

The initialization phase had been done in a somewhat adhoc way,
partially because delta notifications were being handled as top level
gem5 events which were ordered based on their priorities. This change
makes the initialization phase happen more explicitly, and more in the
order in the spec.

Change-Id: I91d56b63fefcb81c845c52c97826a976a7559fad
Reviewed-on: https://gem5-review.googlesource.com/12217
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/kernel.cc

@@ -163,14 +163,7 @@ Kernel::stopWork()
 void
 Kernel::t0Handler()
 {
-    // Now that the event queue has started, mark all the processes that
-    // need to be initialized as ready to run.
-    //
-    // This event has greater priority than delta notifications and so will
-    // happen before them, honoring the ordering for the initialization phase
-    // in the spec. The delta phase will happen at normal priority, and then
-    // the event which runs the processes which is at a lower priority.
-    ::sc_gem5::scheduler.prepareForInit();
+    ::sc_gem5::scheduler.initPhase();
 
     status(::sc_core::SC_RUNNING);
 }

src/systemc/core/scheduler.cc

@@ -46,12 +46,12 @@ Scheduler::Scheduler() :
     starvationEvent(this, false, StarvationPriority),
     _started(false), _paused(false), _stopped(false),
     maxTickEvent(this, false, MaxTickPriority),
-    _numCycles(0), _current(nullptr), initReady(false),
+    _numCycles(0), _current(nullptr), initDone(false),
     runOnce(false)
 {}
 
 void
-Scheduler::prepareForInit()
+Scheduler::initPhase()
 {
     for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) {
         p->finalize();
@@ -64,6 +64,12 @@ Scheduler::prepareForInit()
         p->ready();
     }
 
+    update();
+
+    for (auto &e: deltas)
+        e->run();
+    deltas.clear();
+
     for (auto ets: eventsToSchedule)
         eq->schedule(ets.first, ets.second);
     eventsToSchedule.clear();
@@ -71,13 +77,13 @@ Scheduler::prepareForInit()
     if (_started)
         eq->schedule(&maxTickEvent, maxTick);
 
-    initReady = true;
+    initDone = true;
 }
 
 void
 Scheduler::reg(Process *p)
 {
-    if (initReady) {
+    if (initDone) {
         // If we're past initialization, finalize static sensitivity.
         p->finalize();
         // Mark the process as ready.
@@ -92,7 +98,7 @@ Scheduler::reg(Process *p)
 void
 Scheduler::dontInitialize(Process *p)
 {
-    if (initReady) {
+    if (initDone) {
         // Pop this process off of the ready list.
         p->popListNode();
     } else {
@@ -246,7 +252,7 @@ Scheduler::start(Tick max_tick, bool run_to_time)
     if (starved() && !runToTime)
         return;
 
-    if (initReady) {
+    if (initDone) {
         kernel->status(::sc_core::SC_RUNNING);
         eq->schedule(&maxTickEvent, maxTick);
     }

src/systemc/core/scheduler.hh

@@ -165,8 +165,7 @@ class Scheduler
     uint64_t numCycles() { return _numCycles; }
     Process *current() { return _current; }
 
-    // Prepare for initialization.
-    void prepareForInit();
+    void initPhase();
 
     // Register a process with the scheduler.
     void reg(Process *p);
@@ -226,7 +225,7 @@ class Scheduler
         TimeSlot *&ts = timeSlots[tick];
         if (!ts) {
             ts = new TimeSlot;
-            if (initReady)
+            if (initDone)
                 eq->schedule(ts, tick);
             else
                 eventsToSchedule[ts] = tick;
@@ -256,7 +255,7 @@ class Scheduler
 
         // If no more events are happening at this time slot, get rid of it.
         if (events.empty()) {
-            if (initReady)
+            if (initDone)
                 eq->deschedule(ts);
             else
                 eventsToSchedule.erase(ts);
@@ -363,7 +362,7 @@ class Scheduler
 
     Process *_current;
 
-    bool initReady;
+    bool initDone;
     bool runToTime;
     bool runOnce;