From 7662c12482b45ce34efa16a018978df2a02e916e Mon Sep 17 00:00:00 2001
From: James Cherry <cherry@parallaxsw.com>
Date: Tue, 17 Nov 2020 10:59:19 -0700
Subject: [PATCH] gated clock power

---
 search/Power.cc | 14 +++++------
 search/Sim.cc   | 67 ++++++++++++++++++++++++++++++++++++++++---------
 search/Sim.hh   |  1 +
 3 files changed, 62 insertions(+), 20 deletions(-)

diff --git a/search/Power.cc b/search/Power.cc
index a9e7edec..f20c3b9e 100644
--- a/search/Power.cc
+++ b/search/Power.cc
@@ -340,7 +340,7 @@ PropActivityVisitor::foundRegWithoutActivity() const
 void
 PropActivityVisitor::visit(Vertex *vertex)
 {
-  auto pin = vertex->pin();
+  Pin *pin = vertex->pin();
   debugPrint1(debug_, "power_activity", 3, "visit %s\n",
 	      vertex->name(network_));
   if (power_->hasUserActivity(pin))
@@ -1012,22 +1012,18 @@ PwrActivity
 Power::findClkedActivity(const Pin *pin,
 			 const Clock *inst_clk)
 {
+  PwrActivity activity = findActivity(pin);
   const Clock *clk = findClk(pin);
   if (clk == nullptr)
     clk = inst_clk;
   if (clk) {
     float period = clk->period();
-    if (period > 0.0) {
-      PwrActivity activity = findActivity(pin);
+    if (period > 0.0)
       return PwrActivity(activity.activity() / period,
 			 activity.duty(),
 			 activity.origin());
-    }
   }
-  // gotta find a clock someplace...
-  return PwrActivity(input_activity_.activity(),
-		     input_activity_.duty(),
-		     PwrActivityOrigin::defaulted);
+  return activity;
 }
 
 PwrActivity
@@ -1038,6 +1034,8 @@ Power::findActivity(const Pin *pin)
     return PwrActivity(2.0, 0.5, PwrActivityOrigin::clock);
   else if (global_activity_.isSet())
     return global_activity_;
+  else if (vertex && vertex->isConstant())
+    return PwrActivity(0.0, 0.0, PwrActivityOrigin::constant);
   else if (activity_map_.hasKey(pin)) {
     PwrActivity &activity = activity_map_[pin];
     if (activity.origin() != PwrActivityOrigin::unknown)
diff --git a/search/Sim.cc b/search/Sim.cc
index 21fe0bf1..60cca76d 100644
--- a/search/Sim.cc
+++ b/search/Sim.cc
@@ -913,26 +913,69 @@ Sim::evalInstance(const Instance *inst)
     if (dir->isAnyOutput()) {
       LibertyPort *port = network_->libertyPort(pin);
       if (port) {
+        LogicValue value = LogicValue::unknown;
 	FuncExpr *expr = port->function();
 	if (expr) {
-	  LogicValue value = evalExpr(expr, inst);
-	  FuncExpr *tri_en_expr = port->tristateEnable();
-	  if (tri_en_expr == nullptr
-	      || evalExpr(tri_en_expr, inst) == LogicValue::one) {
-	    debugPrint3(debug_, "sim", 2, " %s %s = %c\n",
-			port->name(),
-			expr->asString(),
-			logicValueString(value));
-	    if (value != logicValue(pin))
-	      setPinValue(pin, value, true);
-	  }
-	}
+          FuncExpr *tri_en_expr = port->tristateEnable();
+          if (tri_en_expr) {
+            if (evalExpr(tri_en_expr, inst) == LogicValue::one) {
+              value = evalExpr(expr, inst);
+              debugPrint3(debug_, "sim", 2, " %s tri_en=1 %s = %c\n",
+                          port->name(),
+                          expr->asString(),
+                          logicValueString(value));
+            }
+          }
+          else {
+            value = evalExpr(expr, inst);
+            debugPrint3(debug_, "sim", 2, " %s %s = %c\n",
+                        port->name(),
+                        expr->asString(),
+                        logicValueString(value));
+          }
+        }
+        else if (port->isClockGateOutPin()) {
+          value = clockGateOutValue(inst);
+          debugPrint2(debug_, "sim", 2, " %s gated_clk = %c\n",
+                      port->name(),
+                      logicValueString(value));
+        }
+        FuncExpr *tri_en_expr = port->tristateEnable();
+        if (tri_en_expr == nullptr
+            || evalExpr(tri_en_expr, inst) == LogicValue::one) {
+          debugPrint3(debug_, "sim", 2, " %s %s = %c\n",
+                      port->name(),
+                      expr ? expr->asString() : "gated_clk",
+                      logicValueString(value));
+          if (value != logicValue(pin))
+            setPinValue(pin, value, true);
+        }
       }
     }
   }
   delete pin_iter;
 }
 
+LogicValue
+Sim::clockGateOutValue(const Instance *inst)
+{
+  LibertyCell *cell = network_->libertyCell(inst);
+  LibertyCellPortIterator port_iter(cell);
+  while (port_iter.hasNext()) {
+    LibertyPort *port = port_iter.next();
+    if (port->isClockGateClockPin()
+        || port->isClockGateEnablePin()) {
+      Pin *gclk_pin = network_->findPin(inst, port);
+      if (gclk_pin) {
+        Vertex *gclk_vertex = graph_->pinLoadVertex(gclk_pin);
+        if (gclk_vertex->simValue() == LogicValue::zero)
+          return LogicValue::zero;
+      }
+    }
+  }
+  return LogicValue::unknown;
+}
+
 void
 Sim::setSimValue(Vertex *vertex,
 		 LogicValue value)
diff --git a/search/Sim.hh b/search/Sim.hh
index aeda7f45..584224f2 100644
--- a/search/Sim.hh
+++ b/search/Sim.hh
@@ -84,6 +84,7 @@ protected:
 			   bool propagate);
   void enqueue(const Instance *inst);
   void evalInstance(const Instance *inst);
+  LogicValue clockGateOutValue(const Instance *inst);
   TimingSense functionSense(const FuncExpr *expr,
 			    const Pin *input_pin,
 			    const Instance *inst);