Add Z80 processor (untested, but complete)

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

EightBit.sln

@@ -11,6 +11,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EightBit.UnitTest", "EightB
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "M6502.Test", "M6502\M6502.Test\M6502.Test.csproj", "{854EDE2F-B54D-425C-8F68-EDA68BDC797E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Z80", "Z80\Z80.csproj", "{C00648C1-BAC1-4EFB-816F-E87C091619D7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -69,6 +71,18 @@ Global
 		{854EDE2F-B54D-425C-8F68-EDA68BDC797E}.Release|x64.Build.0 = Release|Any CPU
 		{854EDE2F-B54D-425C-8F68-EDA68BDC797E}.Release|x86.ActiveCfg = Release|Any CPU
 		{854EDE2F-B54D-425C-8F68-EDA68BDC797E}.Release|x86.Build.0 = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|x64.Build.0 = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Debug|x86.Build.0 = Debug|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|x64.ActiveCfg = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|x64.Build.0 = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|x86.ActiveCfg = Release|Any CPU
+		{C00648C1-BAC1-4EFB-816F-E87C091619D7}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

EightBit/Chip.cs

@@ -51,5 +51,23 @@ namespace EightBit
         public static int PromoteNibble(byte value) => LowByte(value << 4);
 
         public static int DemoteNibble(byte value) => HighNibble(value);
+
+        public static int CountBits(int value)
+        {
+            int count = 0;
+            while (value != 0)
+            {
+                ++count;
+                value &= value - 1;
+            }
+
+            return count;
+        }
+
+        public static int CountBits(byte value) => CountBits((int)value);
+
+        public static bool EvenParity(int value) => CountBits(value) % 2 == 0;
+
+        public static bool EvenParity(byte value) => EvenParity((int)value);
     }
 }

EightBit/IntelOpCodeDecoded.cs

@@ -6,23 +6,27 @@ namespace EightBit
 {
     public class IntelOpCodeDecoded
     {
-        private readonly int x;
-        private readonly int y;
-        private readonly int z;
-        private readonly int p;
-        private readonly int q;
-
         public IntelOpCodeDecoded()
         {
         }
 
         public IntelOpCodeDecoded(byte opCode)
         {
-            this.x = (opCode & 0b11000000) >> 6;    // 0 - 3
+            this.X = (opCode & 0b11000000) >> 6;    // 0 - 3
-            this.y = (opCode & 0b00111000) >> 3;    // 0 - 7
+            this.Y = (opCode & 0b00111000) >> 3;    // 0 - 7
-            this.z = opCode & 0b00000111;           // 0 - 7
+            this.Z = opCode & 0b00000111;           // 0 - 7
-            this.p = (this.y & 0b110) >> 1;         // 0 - 3
+            this.P = (this.Y & 0b110) >> 1;         // 0 - 3
-            this.q = this.y & 1;                    // 0 - 1
+            this.Q = this.Y & 1;                    // 0 - 1
         }
+
+        public int X { get; }
+
+        public int Y { get; }
+
+        public int Z { get; }
+
+        public int P { get; }
+
+        public int Q { get; }
     }
 }

EightBit/IntelProcessor.cs

@@ -8,6 +8,9 @@ namespace EightBit
 
     public abstract class IntelProcessor : LittleEndianProcessor
     {
+        private static readonly int[] HalfCarryTableAdd = new int[8] { 0, 0, 1, 0, 1, 0, 1, 1 };
+        private static readonly int[] HalfCarryTableSub = new int[8] { 0, 1, 1, 1, 0, 0, 0, 1 };
+
         private readonly IntelOpCodeDecoded[] decodedOpCodes = new IntelOpCodeDecoded[0x100];
 
         private Register16 sp = new Register16((ushort)Mask.Mask16);
@@ -86,6 +89,23 @@ namespace EightBit
             this.OnLoweredHALT();
         }
 
+        protected static int BuildHalfCarryIndex(byte before, byte value, int calculation)
+        {
+            return ((before & 0x88) >> 1) | ((value & 0x88) >> 2) | ((calculation & 0x88) >> 3);
+        }
+
+        protected static int CalculateHalfCarryAdd(byte before, byte value, int calculation)
+        {
+            var index = BuildHalfCarryIndex(before, value, calculation);
+            return HalfCarryTableAdd[index & (int)Mask.Mask3];
+        }
+
+        protected static int CalculateHalfCarrySub(byte before, byte value, int calculation)
+        {
+            var index = BuildHalfCarryIndex(before, value, calculation);
+            return HalfCarryTableSub[index & (int)Mask.Mask3];
+        }
+
         protected virtual void OnRaisingHALT() => this.RaisingHALT?.Invoke(this, EventArgs.Empty);
 
         protected virtual void OnRaisedHALT() => this.RaisedHALT?.Invoke(this, EventArgs.Empty);
@@ -192,5 +212,7 @@ namespace EightBit
             ++this.PC();
             this.RaiseHALT();
         }
+
+        protected IntelOpCodeDecoded GetDecodedOpCode(byte opCode) => this.decodedOpCodes[opCode];
     }
 }

EightBit/Mask.cs

@@ -4,8 +4,6 @@
 
 namespace EightBit
 {
-    using System;
-
     public enum Mask
     {
         None = 0,

EightBit/Register16.cs

@@ -76,7 +76,7 @@ namespace EightBit
                 return false;
             }
 
-            Register16 rhs = (Register16)obj;
+            var rhs = (Register16)obj;
             return rhs.Word == this.Word;
         }
 

Z80/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("Z80")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Z80")]
+[assembly: AssemblyCopyright("Copyright ©  2019")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components.  If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("c00648c1-bac1-4efb-816f-e87c091619d7")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

Z80/RefreshRegister.cs

@@ -0,0 +1,59 @@
+namespace EightBit
+{
+    public struct RefreshRegister
+    {
+        private readonly byte high;
+        private byte variable;
+
+        public RefreshRegister(byte value)
+        {
+            this.high = (byte)(value & (byte)Bits.Bit7);
+            this.variable = (byte)(value & (byte)Mask.Mask7);
+        }
+
+        public static implicit operator byte(RefreshRegister input)
+        {
+            return ToByte(input);
+        }
+
+        public static implicit operator RefreshRegister(byte input)
+        {
+            return FromByte(input);
+        }
+
+        public static byte ToByte(RefreshRegister input)
+        {
+            return (byte)((input.high << 7) | input.variable);
+        }
+
+        public static RefreshRegister FromByte(byte input)
+        {
+            return new RefreshRegister(input);
+        }
+
+        public static RefreshRegister operator ++(RefreshRegister value) => Increment(value);
+
+        public static bool operator ==(RefreshRegister left, RefreshRegister right) => left.Equals(right);
+
+        public static bool operator !=(RefreshRegister left, RefreshRegister right) => !(left == right);
+
+        public static RefreshRegister Increment(RefreshRegister value)
+        {
+            ++value.variable;
+            return value;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (!(obj is RefreshRegister))
+            {
+                return false;
+            }
+
+            var rhs = (RefreshRegister)obj;
+            return rhs.high == this.high && rhs.variable == this.variable;
+        }
+
+        public override int GetHashCode() => this.high + this.variable;
+    }
+}

Z80/StatusBits.cs

@@ -0,0 +1,39 @@
+// <copyright file="StatusBits.cs" company="Adrian Conlon">
+// Copyright (c) Adrian Conlon. All rights reserved.
+// </copyright>
+
+namespace EightBit
+{
+    using System;
+
+    [Flags]
+    public enum StatusBits
+    {
+        // Negative
+        SF = Bits.Bit7,
+
+        // Zero
+        ZF = Bits.Bit6,
+
+        // Undocumented Y flag
+        YF = Bits.Bit5,
+
+        // Half carry
+        HC = Bits.Bit4,
+
+        // Undocumented X flag
+        XF = Bits.Bit3,
+
+        // Parity
+        PF = Bits.Bit2,
+
+        // Zero
+        VF = Bits.Bit2,
+
+        // Negative?
+        NF = Bits.Bit1,
+
+        // Carry
+        CF = Bits.Bit0,
+    }
+}

Z80/Z80.csproj

@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{C00648C1-BAC1-4EFB-816F-E87C091619D7}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>Z80</RootNamespace>
+    <AssemblyName>Z80</AssemblyName>
+    <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <LangVersion>latest</LangVersion>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="RefreshRegister.cs" />
+    <Compile Include="StatusBits.cs" />
+    <Compile Include="Z80.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\EightBit\EightBit.csproj">
+      <Project>{6ebf8857-62a3-4ef4-af21-c1844031d7e4}</Project>
+      <Name>EightBit</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>