From 72b5233112a41cb879ca63866f9f0ecf8638dbfb Mon Sep 17 00:00:00 2001
From: Korey Sewell <ksewell@umich.edu>
Date: Fri, 18 Feb 2011 14:29:02 -0500
Subject: [PATCH] inorder: remove events for zero-cycle resources if a resource
 has a zero cycle latency (e.g. RegFile write), then dont allocate an event
 for it to use

---
 src/cpu/inorder/resource.cc          | 20 ++++++++++++++++----
 src/cpu/inorder/resources/use_def.cc |  6 +++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/cpu/inorder/resource.cc b/src/cpu/inorder/resource.cc
index 076084d16..c371f8244 100644
--- a/src/cpu/inorder/resource.cc
+++ b/src/cpu/inorder/resource.cc
@@ -49,7 +49,10 @@ Resource::Resource(string res_name, int res_id, int res_width,
 
 Resource::~Resource()
 {
-    delete [] resourceEvent;
+    if (resourceEvent) {
+        delete [] resourceEvent;
+    }
+
     delete deniedReq;    
 }
 
@@ -57,8 +60,14 @@ Resource::~Resource()
 void
 Resource::init()
 {
-    // Set Up Resource Events to Appropriate Resource BandWidth
-    resourceEvent = new ResourceEvent[width];
+    // If the resource has a zero-cycle (no latency)
+    // function, then no reason to have events
+    // that will process them for the right tick
+    if (latency > 0) {
+        resourceEvent = new ResourceEvent[width];
+    } else {
+        resourceEvent = NULL;
+    }
 
     for (int i = 0; i < width; i++) {
         reqs[i] = new ResourceRequest(this);
@@ -73,7 +82,10 @@ Resource::initSlots()
     // Add available slot numbers for resource
     for (int slot_idx = 0; slot_idx < width; slot_idx++) {
         availSlots.push_back(slot_idx);
-        resourceEvent[slot_idx].init(this, slot_idx);
+
+        if (resourceEvent) {
+            resourceEvent[slot_idx].init(this, slot_idx);
+        }
     }
 }
 
diff --git a/src/cpu/inorder/resources/use_def.cc b/src/cpu/inorder/resources/use_def.cc
index 85bf14500..19246a30b 100644
--- a/src/cpu/inorder/resources/use_def.cc
+++ b/src/cpu/inorder/resources/use_def.cc
@@ -92,7 +92,11 @@ void
 UseDefUnit::init()
 {
     // Set Up Resource Events to Appropriate Resource BandWidth
-    resourceEvent = new ResourceEvent[width];
+    if (latency > 0) {
+        resourceEvent = new ResourceEvent[width];
+    } else {
+        resourceEvent = NULL;
+    }
 
     for (int i = 0; i < width; i++) {
         reqs[i] = new UseDefRequest(this);