From 489b7b21e6e009157d59a836d99f34fff3bae25f Mon Sep 17 00:00:00 2001
From: Adrian Conlon <98398945+AdrianConlon@users.noreply.github.com>
Date: Wed, 18 Sep 2024 11:23:18 +0100
Subject: [PATCH] Clarifications of EightBit library

---
 EightBit/Bus.cs                | 3 +--
 EightBit/Chip.cs               | 4 ----
 EightBit/Device.cs             | 4 ----
 EightBit/InputOutput.cs        | 4 ----
 EightBit/IntelOpCodeDecoded.cs | 6 +-----
 EightBit/MemoryMapping.cs      | 2 +-
 EightBit/Register16.cs         | 2 +-
 EightBit/Rom.cs                | 7 +------
 8 files changed, 5 insertions(+), 27 deletions(-)

diff --git a/EightBit/Bus.cs b/EightBit/Bus.cs
index 95e3d07..1f7aa06 100644
--- a/EightBit/Bus.cs
+++ b/EightBit/Bus.cs
@@ -61,8 +61,7 @@ namespace EightBit
         public void Write()
         {
             this.OnWritingByte();
-            var value = this.Data;       // N.B. Don't join these two lines together: the
-            this.Reference() = value;    // data bus integrity is lost, due to evaluation order!
+            this.Reference() = this.Data;
             this.OnWrittenByte();
         }
 
diff --git a/EightBit/Chip.cs b/EightBit/Chip.cs
index 35b4310..73abd90 100644
--- a/EightBit/Chip.cs
+++ b/EightBit/Chip.cs
@@ -6,10 +6,6 @@ namespace EightBit
 {
     public class Chip : Device
     {
-        protected Chip()
-        {
-        }
-
         public static byte Bit(int which) => (byte)(1 << which);
 
         public static byte Bit(byte which) => Bit((int)which);
diff --git a/EightBit/Device.cs b/EightBit/Device.cs
index 44eb97a..6e83291 100644
--- a/EightBit/Device.cs
+++ b/EightBit/Device.cs
@@ -10,10 +10,6 @@ namespace EightBit
     {
         private PinLevel powerLine;
 
-        protected Device()
-        {
-        }
-
         public event EventHandler<EventArgs>? RaisingPOWER;
 
         public event EventHandler<EventArgs>? RaisedPOWER;
diff --git a/EightBit/InputOutput.cs b/EightBit/InputOutput.cs
index efe5e4c..89bd935 100644
--- a/EightBit/InputOutput.cs
+++ b/EightBit/InputOutput.cs
@@ -11,10 +11,6 @@ namespace EightBit
         private readonly byte[] input = new byte[0x100];
         private readonly byte[] output = new byte[0x100];
 
-        public InputOutput()
-        {
-        }
-
         public event EventHandler<PortEventArgs>? ReadingPort;
 
         public event EventHandler<PortEventArgs>? ReadPort;
diff --git a/EightBit/IntelOpCodeDecoded.cs b/EightBit/IntelOpCodeDecoded.cs
index 41d6476..955ec81 100644
--- a/EightBit/IntelOpCodeDecoded.cs
+++ b/EightBit/IntelOpCodeDecoded.cs
@@ -4,12 +4,8 @@
 
 namespace EightBit
 {
-    public class IntelOpCodeDecoded
+    public sealed class IntelOpCodeDecoded
     {
-        public IntelOpCodeDecoded()
-        {
-        }
-
         public IntelOpCodeDecoded(byte opCode)
         {
             this.X = (opCode & 0b11000000) >> 6;    // 0 - 3
diff --git a/EightBit/MemoryMapping.cs b/EightBit/MemoryMapping.cs
index e3291f1..0dba224 100644
--- a/EightBit/MemoryMapping.cs
+++ b/EightBit/MemoryMapping.cs
@@ -4,7 +4,7 @@
 
 namespace EightBit
 {
-    public class MemoryMapping(Memory memory, ushort begin, ushort mask, AccessLevel access)
+    public sealed class MemoryMapping(Memory memory, ushort begin, ushort mask, AccessLevel access)
     {
         public MemoryMapping(Memory memory, ushort begin, Mask mask, AccessLevel access)
         : this(memory, begin, (ushort)mask, access)
diff --git a/EightBit/Register16.cs b/EightBit/Register16.cs
index 4f43143..48e2467 100644
--- a/EightBit/Register16.cs
+++ b/EightBit/Register16.cs
@@ -7,7 +7,7 @@ namespace EightBit
     using System.Diagnostics;
 
     [DebuggerDisplay("Word = {Word}")]
-    public class Register16
+    public sealed class Register16
     {
         private byte low;
         private byte high;
diff --git a/EightBit/Rom.cs b/EightBit/Rom.cs
index 5a8f202..5a8e36e 100644
--- a/EightBit/Rom.cs
+++ b/EightBit/Rom.cs
@@ -7,15 +7,10 @@ namespace EightBit
     using System;
     using System.IO;
 
-    public class Rom(int size) : Memory
+    public class Rom(int size = 0) : Memory
     {
         private byte[] bytes = new byte[size];
 
-        public Rom()
-        : this(0)
-        {
-        }
-
         public override int Size => this.bytes.Length;
 
         public static int Load(Stream file, ref byte[] output, int writeOffset = 0, int readOffset = 0, int limit = -1, int maximumSize = -1)