Step 2 - 地址生成与拆分

Assets/Tests/EditMode/Step2AddressSplitTests.cs

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+using NUnit.Framework;
+using VMdemo.Core;
+using VMdemo.Simulation;
+
+namespace VMdemo.Tests.EditMode
+{
+    public class Step2AddressSplitTests
+    {
+        [TestCase(32)]
+        [TestCase(48)]
+        [TestCase(64)]
+        public void AddressGenerator_NextVirtualAddress_StaysWithinRange(int vaBits)
+        {
+            var generator = new AddressGenerator(vaBits, seed: 7);
+
+            for (var i = 0; i < 1000; i++)
+            {
+                var va = generator.NextVirtualAddress();
+                Assert.That(va, Is.LessThanOrEqualTo(generator.MaxVirtualAddress));
+            }
+        }
+
+        [Test]
+        public void AddressGenerator_SameSeed_GeneratesDeterministicSequence()
+        {
+            var a = new AddressGenerator(48, seed: 99);
+            var b = new AddressGenerator(48, seed: 99);
+
+            for (var i = 0; i < 20; i++)
+            {
+                Assert.That(a.NextVirtualAddress(), Is.EqualTo(b.NextVirtualAddress()));
+            }
+        }
+
+        [Test]
+        public void AddressGenerator_DifferentSeed_GeneratesDifferentSequence()
+        {
+            var a = new AddressGenerator(48, seed: 99);
+            var b = new AddressGenerator(48, seed: 100);
+            var hasDifference = false;
+
+            for (var i = 0; i < 20; i++)
+            {
+                if (a.NextVirtualAddress() != b.NextVirtualAddress())
+                {
+                    hasDifference = true;
+                    break;
+                }
+            }
+
+            Assert.IsTrue(hasDifference);
+        }
+
+        [TestCase(0x12345ABCUL, 32, 12, 0x12345UL, 0xABCUL, 0x48UL, 0x345UL)]
+        [TestCase(0x0000ABCDEF123456UL, 48, 12, 0xABCDEF123UL, 0x456UL, 0x2AF37UL, 0x2F123UL)]
+        [TestCase(0xFEDCBA9876543210UL, 64, 16, 0xFEDCBA987654UL, 0x3210UL, 0xFEDCBAUL, 0x987654UL)]
+        public void SplitVirtualAddress_SupportedVaBits_ReturnsExpectedParts(
+            ulong va,
+            int vaBits,
+            int offsetBits,
+            ulong expectedVpn,
+            ulong expectedOffset,
+            ulong expectedL1,
+            ulong expectedL2)
+        {
+            var parts = AddressTranslatorUtils.SplitVirtualAddress(va, vaBits, offsetBits);
+            TestContext.WriteLine(AddressTranslatorUtils.FormatSplitResult(va, vaBits, offsetBits, parts));
+
+            Assert.That(parts.Vpn, Is.EqualTo(expectedVpn));
+            Assert.That(parts.Offset, Is.EqualTo(expectedOffset));
+            Assert.That(parts.L1Index, Is.EqualTo(expectedL1));
+            Assert.That(parts.L2Index, Is.EqualTo(expectedL2));
+        }
+
+        [Test]
+        public void SplitVirtualAddress_OddVpnBits_UsesCeilFloorBitSplit()
+        {
+            const int vaBits = 32;
+            const int offsetBits = 13;
+            const ulong va = 0xDEADBEEFUL;
+
+            var parts = AddressTranslatorUtils.SplitVirtualAddress(va, vaBits, offsetBits);
+            AddressTranslatorUtils.GetPageTableBitLayout(vaBits - offsetBits, out var l1Bits, out var l2Bits);
+
+            Assert.That(l1Bits, Is.EqualTo(10));
+            Assert.That(l2Bits, Is.EqualTo(9));
+            Assert.That(parts.Vpn, Is.EqualTo(0x6F56DUL));
+            Assert.That(parts.Offset, Is.EqualTo(0x1EEFUL));
+            Assert.That(parts.L1Index, Is.EqualTo(0x37AUL));
+            Assert.That(parts.L2Index, Is.EqualTo(0x16DUL));
+        }
+
+        [Test]
+        public void GetPageTableBitLayout_AlwaysSumsToVpnBits()
+        {
+            for (var vpnBits = 1; vpnBits <= 63; vpnBits++)
+            {
+                AddressTranslatorUtils.GetPageTableBitLayout(vpnBits, out var l1Bits, out var l2Bits);
+
+                Assert.That(l1Bits + l2Bits, Is.EqualTo(vpnBits));
+                Assert.That(l1Bits, Is.GreaterThanOrEqualTo(l2Bits));
+                Assert.That(l1Bits - l2Bits, Is.LessThanOrEqualTo(1));
+            }
+        }
+
+        [Test]
+        public void SplitVirtualAddress_AddressOutOfRange_Throws()
+        {
+            Assert.Throws<System.ArgumentOutOfRangeException>(() =>
+                AddressTranslatorUtils.SplitVirtualAddress(0x1_0000_0000UL, 32, 12));
+        }
+    }
+}

Assets/Tests/EditMode/Step2AddressSplitTests.cs.meta

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