Start adding some LDx tests, mainly to mop up any missing indexed addressing modes.

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>

MC6809/MC6809.UnitTest/LdTests.cs

@@ -0,0 +1,67 @@
+// <copyright file="LdTests.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class LdTests
+    {
+        private readonly Board board = new Board();
+        private readonly MC6809 cpu;
+
+        public LdTests() => this.cpu = this.board.CPU;
+
+        [TestInitialize]
+        public void Initialise()
+        {
+            this.board.RaisePOWER();
+            this.cpu.Step(); // Step over the reset
+        }
+
+        [TestCleanup]
+        public void Cleanup() => this.board.LowerPOWER();
+
+        [TestMethod]
+        public void TestIndexedAccumulatorOffset_A()
+        {
+            this.board.Poke(0, 0xe6);
+            this.board.Poke(1, 0x86);
+            this.cpu.A = 0x2b;
+            this.cpu.B = 0x00;
+            this.cpu.X.Word = 0xc300;
+            this.board.Poke(0xc32b, 0x4e);
+            this.cpu.Step();
+            Assert.AreEqual(0x4e, this.cpu.B);
+        }
+
+        [TestMethod]
+        public void TestIndexedAccumulatorOffset_B()
+        {
+            this.board.Poke(0, 0xa6);
+            this.board.Poke(1, 0x85);
+            this.cpu.A = 0x00;
+            this.cpu.B = 0x2b;
+            this.cpu.X.Word = 0xc300;
+            this.board.Poke(0xc32b, 0x4e);
+            this.cpu.Step();
+            Assert.AreEqual(0x4e, this.cpu.A);
+        }
+
+        [TestMethod]
+        public void TestIndirectIndexedAccumulatorOffset()
+        {
+            this.board.Poke(0, 0xa6);
+            this.board.Poke(1, 0x95);
+            this.cpu.A = 0x00;
+            this.cpu.B = 0x2b;
+            this.cpu.X.Word = 0xc300;
+            this.cpu.PokeWord(0xc32b, 0x1234);
+            this.board.Poke(0x1234, 0x56);
+            this.cpu.Step();
+            Assert.AreEqual(0x56, this.cpu.A);
+        }
+    }
+}

MC6809/MC6809.UnitTest/MC6809.UnitTest.csproj

@@ -87,6 +87,7 @@
     <Compile Include="LeaTests.cs" />
     <Compile Include="MulTests.cs" />
     <Compile Include="DaaTests.cs" />
+    <Compile Include="LdTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\EightBit\EightBit.csproj">