Step 5 - 翻译引擎（单步状态机）

Assets/Tests/EditMode/Step1CoreModelTests.cs

@@ -123,11 +123,15 @@ namespace VMdemo.Tests.EditMode
             state.Reset();
 
             Assert.That(state.CurrentRound, Is.EqualTo(0));
+            Assert.That(state.CurrentStep, Is.EqualTo(TranslationStep.GenerateVA));
             Assert.That(state.CurrentVirtualAddress, Is.EqualTo(0UL));
             Assert.That(state.CurrentAddressParts.Vpn, Is.EqualTo(0UL));
             Assert.That(state.CurrentAddressParts.Offset, Is.EqualTo(0UL));
             Assert.That(state.CurrentAddressParts.L1Index, Is.EqualTo(0UL));
             Assert.That(state.CurrentAddressParts.L2Index, Is.EqualTo(0UL));
+            Assert.That(state.CurrentPhysicalAddress, Is.EqualTo(0UL));
+            Assert.That(state.CurrentPfn, Is.EqualTo(0UL));
+            Assert.IsFalse(state.HasCurrentPfn);
             Assert.IsFalse(state.IsPageFault);
             Assert.IsFalse(state.IsTlbHit);
             Assert.IsFalse(state.IsPageTableHit);

Assets/Tests/EditMode/Step5TranslatorEngineTests.cs

@@ -0,0 +1,192 @@
+using System.Collections.Generic;
+using NUnit.Framework;
+using VMdemo.Core;
+using VMdemo.Simulation;
+
+namespace VMdemo.Tests.EditMode
+{
+    public class Step5TranslatorEngineTests
+    {
+        [Test]
+        public void StepOnce_FirstAccess_VisitsAllStagesInOrder()
+        {
+            var engine = CreateEngine(frameCountMb: 1, tlbEntries: 4, seed: 77);
+            engine.SetNextVirtualAddress(0x0000_1234UL);
+
+            var visited = new List<TranslationStep>();
+            bool completed;
+            do
+            {
+                visited.Add(engine.CurrentStep);
+                completed = engine.StepOnce();
+            } while (!completed);
+
+            var expected = new[]
+            {
+                TranslationStep.GenerateVA,
+                TranslationStep.SplitVA,
+                TranslationStep.LookupTLB,
+                TranslationStep.LookupPageTable,
+                TranslationStep.HandlePageFault,
+                TranslationStep.ComposePA,
+                TranslationStep.Finalize
+            };
+
+            CollectionAssert.AreEqual(expected, visited);
+            Assert.That(engine.State.CurrentRound, Is.EqualTo(1));
+            Assert.That(engine.CurrentStep, Is.EqualTo(TranslationStep.GenerateVA));
+        }
+
+        [Test]
+        public void StepOnce_TlbHitPath_SkipsPageTableAndFaultStages()
+        {
+            var engine = CreateEngine(frameCountMb: 1, tlbEntries: 4, seed: 88);
+            const ulong va = 0x0000_4567UL;
+
+            engine.RunOneAccess(va); // warmup: make resident + populate tlb
+
+            engine.SetNextVirtualAddress(va);
+            var visited = new List<TranslationStep>();
+            bool completed;
+            do
+            {
+                visited.Add(engine.CurrentStep);
+                completed = engine.StepOnce();
+            } while (!completed);
+
+            var expected = new[]
+            {
+                TranslationStep.GenerateVA,
+                TranslationStep.SplitVA,
+                TranslationStep.LookupTLB,
+                TranslationStep.ComposePA,
+                TranslationStep.Finalize
+            };
+
+            CollectionAssert.AreEqual(expected, visited);
+            Assert.IsTrue(engine.State.IsTlbHit);
+            Assert.IsFalse(engine.State.IsPageFault);
+        }
+
+        [Test]
+        public void StepOnce_PageTableHitPath_WritesBackToTlb()
+        {
+            var engine = CreateEngine(frameCountMb: 1, tlbEntries: 2, seed: 99);
+            const ulong va = 0x0000_89ABUL;
+            var parts = AddressTranslatorUtils.SplitVirtualAddress(va, 32, engine.OffsetBits);
+
+            engine.PageTable.SetPresent(parts.L1Index, parts.L2Index, pfn: 3UL);
+            engine.SetNextVirtualAddress(va);
+
+            var visited = new List<TranslationStep>();
+            bool completed;
+            do
+            {
+                visited.Add(engine.CurrentStep);
+                completed = engine.StepOnce();
+            } while (!completed);
+
+            var expected = new[]
+            {
+                TranslationStep.GenerateVA,
+                TranslationStep.SplitVA,
+                TranslationStep.LookupTLB,
+                TranslationStep.LookupPageTable,
+                TranslationStep.ComposePA,
+                TranslationStep.Finalize
+            };
+
+            CollectionAssert.AreEqual(expected, visited);
+            Assert.IsFalse(engine.State.IsTlbHit);
+            Assert.IsTrue(engine.State.IsPageTableHit);
+            Assert.IsFalse(engine.State.IsPageFault);
+            Assert.IsTrue(engine.TlbCache.TryLookup(parts.Vpn, out var cachedPfn));
+            Assert.That(cachedPfn, Is.EqualTo(3UL));
+        }
+
+        [Test]
+        public void RunOneAccess_WhenMemoryFull_ProducesEvictionInfoAndSyncsState()
+        {
+            var config = new SimulationConfig
+            {
+                vaBits = 32,
+                pageSizeKB = 1024, // 1MB per page
+                physicalMemoryMB = 1, // 1 frame total
+                tlbEntries = 4,
+                accessCount = 10,
+                pageFaultPenalty = 100
+            };
+            var engine = new TranslatorEngine(config, seed: 11);
+
+            var first = engine.RunOneAccess(0x0000_0123UL);
+            var second = engine.RunOneAccess(0x0010_0123UL); // different VPN
+
+            Assert.IsTrue(first.PageFault);
+            Assert.IsTrue(second.PageFault);
+            Assert.IsTrue(second.Eviction.HasEvicted);
+            Assert.That(second.Eviction.EvictedVpn, Is.EqualTo(first.AddressParts.Vpn));
+            Assert.IsFalse(engine.TlbCache.TryLookup(first.AddressParts.Vpn, out _));
+            Assert.That(engine.LastEviction.EvictedVpn, Is.EqualTo(first.AddressParts.Vpn));
+        }
+
+        [Test]
+        public void RunOneAccess_ForcedVa_MatchesStepByStepOutcome()
+        {
+            const ulong va = 0x00AB_CDEFUL;
+
+            var engineA = CreateEngine(frameCountMb: 1, tlbEntries: 4, seed: 123);
+            var result = engineA.RunOneAccess(va);
+
+            var engineB = CreateEngine(frameCountMb: 1, tlbEntries: 4, seed: 123);
+            engineB.SetNextVirtualAddress(va);
+            while (!engineB.StepOnce())
+            {
+            }
+
+            Assert.That(engineB.State.CurrentVirtualAddress, Is.EqualTo(result.VirtualAddress));
+            Assert.That(engineB.State.CurrentAddressParts.Vpn, Is.EqualTo(result.AddressParts.Vpn));
+            Assert.That(engineB.State.CurrentPfn, Is.EqualTo(result.Pfn));
+            Assert.That(engineB.State.CurrentPhysicalAddress, Is.EqualTo(result.PhysicalAddress));
+            Assert.That(engineB.State.IsPageFault, Is.EqualTo(result.PageFault));
+            Assert.That(engineB.State.IsPageTableHit, Is.EqualTo(result.PageTableHit));
+            Assert.That(engineB.State.IsTlbHit, Is.EqualTo(result.TlbHit));
+            Assert.That(engineB.State.CurrentRound, Is.EqualTo(result.Round));
+        }
+
+        [Test]
+        public void Reset_ClearsStateAndRuntimeCaches()
+        {
+            var engine = CreateEngine(frameCountMb: 1, tlbEntries: 4, seed: 222);
+            engine.RunOneAccess(0x0000_1000UL);
+
+            Assert.That(engine.State.CurrentRound, Is.EqualTo(1));
+            Assert.That(engine.TlbCache.Count, Is.GreaterThan(0));
+            Assert.That(engine.PhysicalMemoryManager.ResidentCount, Is.GreaterThan(0));
+
+            engine.Reset();
+
+            Assert.That(engine.State.CurrentRound, Is.EqualTo(0));
+            Assert.That(engine.State.CurrentStep, Is.EqualTo(TranslationStep.GenerateVA));
+            Assert.That(engine.State.CurrentVirtualAddress, Is.EqualTo(0UL));
+            Assert.That(engine.State.HasCurrentPfn, Is.False);
+            Assert.That(engine.TlbCache.Count, Is.EqualTo(0));
+            Assert.That(engine.PhysicalMemoryManager.ResidentCount, Is.EqualTo(0));
+            Assert.That(engine.LastEviction.HasEvicted, Is.False);
+        }
+
+        private static TranslatorEngine CreateEngine(int frameCountMb, int tlbEntries, int seed)
+        {
+            var config = new SimulationConfig
+            {
+                vaBits = 32,
+                pageSizeKB = 4,
+                physicalMemoryMB = frameCountMb,
+                tlbEntries = tlbEntries,
+                accessCount = 10,
+                pageFaultPenalty = 100
+            };
+
+            return new TranslatorEngine(config, seed);
+        }
+    }
+}

Assets/Tests/EditMode/Step5TranslatorEngineTests.cs.meta

@@ -0,0 +1,11 @@
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