From 360ccd92698f39160f639524083e442b9ef34778 Mon Sep 17 00:00:00 2001
From: Sindre Stephansen <sindre@sindrestephansen.com>
Date: Fri, 22 Nov 2019 16:00:05 +0100
Subject: [PATCH] Implement profiling tests

---
 src/test/scala/RISCV/testRunner.scala | 100 +++++++++++++++++++++++++-
 1 file changed, 99 insertions(+), 1 deletion(-)

diff --git a/src/test/scala/RISCV/testRunner.scala b/src/test/scala/RISCV/testRunner.scala
index 3d9d60c..33b0bbb 100644
--- a/src/test/scala/RISCV/testRunner.scala
+++ b/src/test/scala/RISCV/testRunner.scala
@@ -165,7 +165,48 @@ object TestRunner {
         helper(events, initState)
       }
 
+      /**
+        * This is profiler for a 2-bit 8-slot branch predictor.
+        */
+      def TwoBitEightSlots(events: List[BranchEvent]): Int = {
+        // Uncomment to take a look at the event log
+        // say(events.mkString("\n","\n","\n"))
+
+        // Helper inspects the next element of the event list. If the event is a mispredict the prediction table is updated
+        // to reflect this.
+        // As long as there are remaining events the helper calls itself recursively on the remainder
+        def helper(events: List[BranchEvent], predictionTable: Map[Int, Int]): Int = {
+          events match {
+            case Taken(from, to) :: t if(predictionTable(hash(from)) == 0) => 1 + helper(t, predictionTable.updated(hash(from), 1))
+            case Taken(from, to) :: t if(predictionTable(hash(from)) == 1) => 1 + helper(t, predictionTable.updated(hash(from), 2))
+            case Taken(from, to) :: t if(predictionTable(hash(from)) == 2) => helper(t, predictionTable.updated(hash(from), 3))
+            case Taken(from, to) :: t if(predictionTable(hash(from)) == 3) => helper(t, predictionTable)
+            case NotTaken(addr)  :: t if(predictionTable(hash(addr)) == 0) => helper(t, predictionTable)
+            case NotTaken(addr)  :: t if(predictionTable(hash(addr)) == 1) => helper(t, predictionTable.updated(hash(addr), 0))
+            case NotTaken(addr)  :: t if(predictionTable(hash(addr)) == 2) => 1 + helper(t, predictionTable.updated(hash(addr), 1))
+            case NotTaken(addr)  :: t if(predictionTable(hash(addr)) == 3) => 1 + helper(t, predictionTable.updated(hash(addr), 2))
+            case Nil => 0
+          }
+        }
+
+        def hash(addr: Int): Int = addr.getTag(8)
+
+        def initState = Map(
+          0 -> 0,
+          1 -> 0,
+          2 -> 0,
+          3 -> 0,
+          4 -> 0,
+          5 -> 0,
+          6 -> 0,
+          7 -> 0,
+        )
+
+        helper(events, initState)
+      }
+
       say(OneBitInfiniteSlots(events))
+      say(TwoBitEightSlots(events))
     }
 
 
@@ -190,9 +231,66 @@ object TestRunner {
         case MemRead(x,_) => Read(x.value)
       }
 
-      // Your cache here
+      case class CacheEntry(var tag: Int, var lru: Boolean)
+      type Cache = Map[Int, List[CacheEntry]]
+
+      /**
+        * This is profiler for a 2-way associative 4 word cache
+        */
+      def TwoWayFourWord(events: List[MemoryEvent]): Int = {
+        def helper(events: List[MemoryEvent], cache: Cache): Int = {
+          events match {
+            case Write(addr) :: t => helper(t, cache)
+            case Read(addr)  :: t if( inCache(addr, cache)) => 1+helper(t, useCache(addr, cache))
+            case Read(addr)  :: t if(!inCache(addr, cache)) => helper(t, addToCache(addr, cache))
+            case Nil => say(cache); 0
+          }
+        }
+
+        def getIndex(addr: Int): Int = addr.getTag(2)
+        def getTag(addr: Int): Int = addr >>> 3
+
+        def inCache(addr: Int, cache: Cache): Boolean = {
+          cache(getIndex(addr))(0).tag == getTag(addr) || cache(getIndex(addr))(1).tag == getTag(addr)
+        }
+
+        def useCache(addr: Int, cache: Cache): Cache = {
+          if (cache(getIndex(addr))(0).tag == getTag(addr)) {
+            cache(getIndex(addr))(0).lru = false
+            cache(getIndex(addr))(1).lru = true
+          } else {
+            cache(getIndex(addr))(1).lru = false
+            cache(getIndex(addr))(0).lru = true
+          }
+
+          cache
+        }
+
+        def addToCache(addr: Int, cache: Cache): Cache = {
+          if (cache(getIndex(addr))(0).lru) {
+            cache(getIndex(addr))(0).tag = getTag(addr)
+            cache(getIndex(addr))(0).lru = false
+            cache(getIndex(addr))(1).lru = true
+          } else {
+            cache(getIndex(addr))(1).tag = getTag(addr)
+            cache(getIndex(addr))(1).lru = false
+            cache(getIndex(addr))(0).lru = true
+          }
+
+          cache
+        }
 
+        def initState = Map(
+          0 -> List(CacheEntry(-1, true), CacheEntry(-1, true)),
+          1 -> List(CacheEntry(-1, true), CacheEntry(-1, true)),
+        )
+
+        helper(events, initState)
+      }
+
+      say(TwoWayFourWord(events))
     }
+
     true
   }
 }