349 lines
13 KiB
C#
349 lines
13 KiB
C#
using System;
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using VMdemo.Core;
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namespace VMdemo.Simulation
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{
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public enum TranslationStep
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{
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GenerateVA = 0,
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SplitVA = 1,
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LookupTLB = 2,
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LookupPageTable = 3,
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HandlePageFault = 4,
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ComposePA = 5,
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Finalize = 6
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}
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public readonly struct AccessExecutionResult
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{
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public AccessExecutionResult(
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int round,
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ulong virtualAddress,
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AddressParts addressParts,
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ulong pfn,
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ulong physicalAddress,
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bool tlbHit,
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bool pageTableHit,
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bool pageFault,
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EvictionInfo eviction)
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{
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Round = round;
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VirtualAddress = virtualAddress;
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AddressParts = addressParts;
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Pfn = pfn;
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PhysicalAddress = physicalAddress;
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TlbHit = tlbHit;
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PageTableHit = pageTableHit;
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PageFault = pageFault;
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Eviction = eviction;
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}
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public int Round { get; }
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public ulong VirtualAddress { get; }
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public AddressParts AddressParts { get; }
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public ulong Pfn { get; }
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public ulong PhysicalAddress { get; }
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public bool TlbHit { get; }
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public bool PageTableHit { get; }
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public bool PageFault { get; }
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public EvictionInfo Eviction { get; }
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}
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public class TranslatorEngine
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{
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private readonly SimulationConfig _config;
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private readonly ConfigValidator.DerivedConfig _derivedConfig;
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private readonly int? _seed;
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private AddressGenerator _addressGenerator;
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private TlbCache _tlbCache;
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private TwoLevelPageTable _pageTable;
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private PhysicalMemoryManager _physicalMemoryManager;
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private bool _hasPendingForcedVirtualAddress;
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private ulong _pendingForcedVirtualAddress;
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private EvictionInfo _lastEviction;
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public TranslatorEngine(SimulationConfig config, int? seed = null)
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{
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if (!ConfigValidator.TryValidateAndBuildDerived(config, out var derived, out var errorMessage))
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{
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throw new ArgumentException(errorMessage, nameof(config));
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}
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_config = config;
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_derivedConfig = derived;
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_seed = seed;
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State = new SimulationState();
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Stats = new StatsCollector();
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AddressTranslatorUtils.GetPageTableBitLayout(derived.VpnBits, out var l1Bits, out var l2Bits);
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L1Bits = l1Bits;
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L2Bits = l2Bits;
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_addressGenerator = CreateAddressGenerator();
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_tlbCache = new TlbCache(_config.tlbEntries);
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_pageTable = new TwoLevelPageTable(L1Bits, L2Bits);
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_physicalMemoryManager = new PhysicalMemoryManager(_derivedConfig.FrameCount);
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Reset();
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}
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public SimulationState State { get; }
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public TranslationStep CurrentStep => State.CurrentStep;
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public int MachineBits => _config.machineBits;
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public int VaBits => _config.vaBits;
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public int PageSizeKB => _config.pageSizeKB;
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public int PhysicalMemoryMB => _config.physicalMemoryMB;
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public int OffsetBits => _derivedConfig.OffsetBits;
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public int L1Bits { get; }
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public int L2Bits { get; }
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public ulong MaxVirtualAddress => _addressGenerator.MaxVirtualAddress;
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public TlbCache TlbCache => _tlbCache;
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public TwoLevelPageTable PageTable => _pageTable;
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public PhysicalMemoryManager PhysicalMemoryManager => _physicalMemoryManager;
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public StatsCollector Stats { get; }
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public EvictionInfo LastEviction => _lastEviction;
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public void Reset()
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{
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State.Reset();
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_lastEviction = EvictionInfo.None;
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_hasPendingForcedVirtualAddress = false;
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_pendingForcedVirtualAddress = 0UL;
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Stats.Reset();
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_addressGenerator = CreateAddressGenerator();
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_tlbCache = new TlbCache(_config.tlbEntries);
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_pageTable = new TwoLevelPageTable(L1Bits, L2Bits);
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_physicalMemoryManager = new PhysicalMemoryManager(_derivedConfig.FrameCount);
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}
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public void SetNextVirtualAddress(ulong virtualAddress)
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{
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EnsureVirtualAddressInRange(virtualAddress);
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_pendingForcedVirtualAddress = virtualAddress;
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_hasPendingForcedVirtualAddress = true;
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}
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public bool StepOnce()
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{
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switch (State.CurrentStep)
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{
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case TranslationStep.GenerateVA:
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ExecuteGenerateVa();
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return false;
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case TranslationStep.SplitVA:
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ExecuteSplitVa();
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return false;
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case TranslationStep.LookupTLB:
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ExecuteLookupTlb();
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return false;
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case TranslationStep.LookupPageTable:
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ExecuteLookupPageTable();
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return false;
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case TranslationStep.HandlePageFault:
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ExecuteHandlePageFault();
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return false;
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case TranslationStep.ComposePA:
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ExecuteComposePa();
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return false;
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case TranslationStep.Finalize:
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ExecuteFinalize();
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return true;
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default:
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throw new InvalidOperationException($"未知翻译步骤：{State.CurrentStep}");
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}
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}
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public AccessExecutionResult RunOneAccess(ulong? forcedVirtualAddress = null)
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{
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if (State.CurrentStep != TranslationStep.GenerateVA)
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{
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throw new InvalidOperationException("RunOneAccess 只能在 GenerateVA 起始步骤调用。");
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}
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if (forcedVirtualAddress.HasValue)
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{
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SetNextVirtualAddress(forcedVirtualAddress.Value);
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}
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while (!StepOnce())
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{
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}
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return new AccessExecutionResult(
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State.CurrentRound,
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State.CurrentVirtualAddress,
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State.CurrentAddressParts,
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State.CurrentPfn,
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State.CurrentPhysicalAddress,
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State.IsTlbHit,
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State.IsPageTableHit,
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State.IsPageFault,
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_lastEviction);
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}
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private void ExecuteGenerateVa()
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{
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State.IsTlbHit = false;
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State.IsPageTableHit = false;
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State.IsPageFault = false;
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State.CurrentCost = 0;
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State.CurrentAddressParts = AddressParts.Empty;
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State.CurrentPhysicalAddress = 0UL;
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State.CurrentPfn = 0UL;
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State.HasCurrentPfn = false;
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State.LastDecisionReason = "已生成本轮虚拟地址，准备进行地址拆分。";
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_lastEviction = EvictionInfo.None;
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if (_hasPendingForcedVirtualAddress)
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{
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State.CurrentVirtualAddress = _pendingForcedVirtualAddress;
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_hasPendingForcedVirtualAddress = false;
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_pendingForcedVirtualAddress = 0UL;
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}
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else
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{
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State.CurrentVirtualAddress = _addressGenerator.NextVirtualAddress();
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}
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State.CurrentStep = TranslationStep.SplitVA;
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}
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private void ExecuteSplitVa()
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{
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State.CurrentAddressParts = AddressTranslatorUtils.SplitVirtualAddress(
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State.CurrentVirtualAddress,
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_config.vaBits,
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_derivedConfig.OffsetBits);
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State.LastDecisionReason = "已拆分 VA 为 VPN/Offset，并从 VPN 拆分出 L1/L2 索引。";
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State.CurrentStep = TranslationStep.LookupTLB;
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}
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private void ExecuteLookupTlb()
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{
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if (_tlbCache.TryLookup(State.CurrentAddressParts.Vpn, out var pfn))
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{
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State.IsTlbHit = true;
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State.CurrentPfn = pfn;
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State.HasCurrentPfn = true;
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State.LastDecisionReason =
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$"TLB 命中：VPN={State.CurrentAddressParts.Vpn} 命中 PFN={pfn}，跳过页表，直接合成物理地址。";
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State.CurrentStep = TranslationStep.ComposePA;
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return;
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}
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State.LastDecisionReason =
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$"TLB 未命中：VPN={State.CurrentAddressParts.Vpn} 未找到映射，转入页表查询。";
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State.CurrentStep = TranslationStep.LookupPageTable;
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}
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private void ExecuteLookupPageTable()
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{
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var probe = _pageTable.Probe(State.CurrentAddressParts.L1Index, State.CurrentAddressParts.L2Index);
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if (probe.Status == PageTableProbeStatus.PresentEntry)
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{
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State.IsPageTableHit = true;
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State.CurrentPfn = probe.Entry.Pfn;
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State.HasCurrentPfn = true;
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_tlbCache.InsertOrUpdate(State.CurrentAddressParts.Vpn, probe.Entry.Pfn);
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State.LastDecisionReason =
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$"页表命中：L1={State.CurrentAddressParts.L1Index}, L2={State.CurrentAddressParts.L2Index}, PFN={probe.Entry.Pfn}，并写回 TLB。";
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State.CurrentStep = TranslationStep.ComposePA;
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return;
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}
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State.LastDecisionReason = probe.Status switch
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{
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PageTableProbeStatus.MissingL1Table =>
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$"页表未命中：L1={State.CurrentAddressParts.L1Index} 对应二级页表不存在，触发缺页处理。",
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PageTableProbeStatus.MissingL2Entry =>
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$"页表未命中：L2={State.CurrentAddressParts.L2Index} 页表项不存在，触发缺页处理。",
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PageTableProbeStatus.NotPresentEntry =>
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$"页表项无效：L2={State.CurrentAddressParts.L2Index} present=false，触发缺页处理。",
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_ => "页表未命中，触发缺页处理。"
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};
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State.CurrentStep = TranslationStep.HandlePageFault;
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}
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private void ExecuteHandlePageFault()
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{
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var result = MemoryAccessResolver.Resolve(
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State.CurrentAddressParts.Vpn,
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State.CurrentAddressParts.L1Index,
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State.CurrentAddressParts.L2Index,
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_pageTable,
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_physicalMemoryManager,
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_tlbCache);
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State.IsPageTableHit = result.PageTableHit;
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State.IsPageFault = result.PageFault;
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State.CurrentPfn = result.Pfn;
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State.HasCurrentPfn = true;
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_lastEviction = result.Eviction;
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State.LastDecisionReason = result.Eviction.HasEvicted
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? $"缺页处理完成：装入 PFN={result.Pfn}，并按 FIFO 淘汰 VPN={result.Eviction.EvictedVpn}。"
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: $"缺页处理完成：装入 PFN={result.Pfn}，当前仍有空闲物理帧。";
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State.CurrentStep = TranslationStep.ComposePA;
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}
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private void ExecuteComposePa()
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{
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if (!State.HasCurrentPfn)
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{
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throw new InvalidOperationException("ComposePA 阶段缺少 PFN，无法合成物理地址。");
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}
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State.CurrentPhysicalAddress =
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(State.CurrentPfn << _derivedConfig.OffsetBits) | State.CurrentAddressParts.Offset;
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State.LastDecisionReason =
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$"物理地址合成：PA = (PFN << offsetBits) | offset = ({State.CurrentPfn} << {_derivedConfig.OffsetBits}) | {State.CurrentAddressParts.Offset}。";
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State.CurrentStep = TranslationStep.Finalize;
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}
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private void ExecuteFinalize()
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{
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State.CurrentCost = Stats.CalculateCost(
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State.IsTlbHit,
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State.IsPageTableHit,
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State.IsPageFault,
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_config.pageFaultPenalty);
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Stats.RecordAccess(
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State.IsTlbHit,
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State.IsPageTableHit,
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State.IsPageFault,
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State.CurrentCost);
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State.LastDecisionReason = State.IsPageFault
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? $"本轮完成：TLB 未命中 + 页表未命中，发生缺页，开销={State.CurrentCost}。"
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: State.IsTlbHit
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? $"本轮完成：TLB 命中，开销={State.CurrentCost}。"
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: $"本轮完成：TLB 未命中 + 页表命中，开销={State.CurrentCost}。";
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State.CurrentRound += 1;
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State.CurrentStep = TranslationStep.GenerateVA;
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}
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private void EnsureVirtualAddressInRange(ulong virtualAddress)
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{
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if (virtualAddress > _addressGenerator.MaxVirtualAddress)
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{
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throw new ArgumentOutOfRangeException(nameof(virtualAddress), "virtualAddress 超出 vaBits 可表示范围。");
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}
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}
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private AddressGenerator CreateAddressGenerator()
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{
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return new AddressGenerator(
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_config.vaBits,
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_seed,
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_config.addressGenerationMode,
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_config.arrayLengthBytes,
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_config.arrayElementBytes,
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_config.arrayBaseAddress);
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}
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}
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}
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