Step 3 - TLB（全相联 + LRU）

Assets/Scripts/Simulation/TlbCache.cs

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+using System;
+using System.Collections.Generic;
+
+namespace VMdemo.Simulation
+{
+    public class TlbCache
+    {
+        private readonly Dictionary<ulong, LinkedListNode<TlbEntry>> _index;
+        private readonly LinkedList<TlbEntry> _lruList;
+
+        public TlbCache(int capacity)
+        {
+            if (capacity <= 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(capacity), "TLB 容量必须是正整数。");
+            }
+
+            Capacity = capacity;
+            _index = new Dictionary<ulong, LinkedListNode<TlbEntry>>(capacity);
+            _lruList = new LinkedList<TlbEntry>();
+        }
+
+        public int Capacity { get; }
+        public int Count => _index.Count;
+        public int HitCount { get; private set; }
+        public int MissCount { get; private set; }
+
+        public bool Lookup(ulong vpn, out ulong pfn)
+        {
+            return TryLookup(vpn, out pfn);
+        }
+
+        public bool TryLookup(ulong vpn, out ulong pfn)
+        {
+            if (_index.TryGetValue(vpn, out var node) && node.Value.IsValid)
+            {
+                MoveToMostRecent(node);
+                pfn = node.Value.Pfn;
+                HitCount++;
+                return true;
+            }
+
+            pfn = 0UL;
+            MissCount++;
+            return false;
+        }
+
+        public void InsertOrUpdate(ulong vpn, ulong pfn)
+        {
+            if (_index.TryGetValue(vpn, out var existingNode))
+            {
+                existingNode.Value = existingNode.Value.WithPfn(pfn);
+                MoveToMostRecent(existingNode);
+                return;
+            }
+
+            var newNode = new LinkedListNode<TlbEntry>(new TlbEntry(vpn, pfn));
+            _lruList.AddFirst(newNode);
+            _index[vpn] = newNode;
+
+            if (_index.Count > Capacity)
+            {
+                EvictLeastRecent();
+            }
+        }
+
+        public bool Remove(ulong vpn)
+        {
+            if (!_index.TryGetValue(vpn, out var node))
+            {
+                return false;
+            }
+
+            _lruList.Remove(node);
+            _index.Remove(vpn);
+            return true;
+        }
+
+        public void Clear()
+        {
+            _lruList.Clear();
+            _index.Clear();
+            HitCount = 0;
+            MissCount = 0;
+        }
+
+        public IReadOnlyList<TlbEntry> GetEntriesMostRecentFirst()
+        {
+            var snapshot = new List<TlbEntry>(_index.Count);
+            for (var node = _lruList.First; node != null; node = node.Next)
+            {
+                snapshot.Add(node.Value);
+            }
+
+            return snapshot;
+        }
+
+        private void MoveToMostRecent(LinkedListNode<TlbEntry> node)
+        {
+            if (node.List != _lruList || _lruList.First == node)
+            {
+                return;
+            }
+
+            _lruList.Remove(node);
+            _lruList.AddFirst(node);
+        }
+
+        private void EvictLeastRecent()
+        {
+            var leastRecentNode = _lruList.Last;
+            if (leastRecentNode == null)
+            {
+                return;
+            }
+
+            _lruList.RemoveLast();
+            _index.Remove(leastRecentNode.Value.Vpn);
+        }
+    }
+}

Assets/Scripts/Simulation/TlbCache.cs.meta

@@ -0,0 +1,11 @@
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+  externalObjects: {}
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+  defaultReferences: []
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Assets/Scripts/Simulation/TlbEntry.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace VMdemo.Simulation
+{
+    [Serializable]
+    public readonly struct TlbEntry
+    {
+        public TlbEntry(ulong vpn, ulong pfn, bool isValid = true)
+        {
+            Vpn = vpn;
+            Pfn = pfn;
+            IsValid = isValid;
+        }
+
+        public ulong Vpn { get; }
+        public ulong Pfn { get; }
+        public bool IsValid { get; }
+
+        public TlbEntry WithPfn(ulong pfn)
+        {
+            return new TlbEntry(Vpn, pfn, true);
+        }
+
+        public override string ToString()
+        {
+            return $"VPN={Vpn}, PFN={Pfn}, Valid={IsValid}";
+        }
+    }
+}

Assets/Scripts/Simulation/TlbEntry.cs.meta

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