From 726c3fe4cc7860ce9e480f873251989fce4ee7b2 Mon Sep 17 00:00:00 2001
From: Adrian Conlon <Adrian.conlon@gmail.com>
Date: Thu, 21 Feb 2019 22:52:46 +0000
Subject: [PATCH] More work on minimising the effect of creating garbage
 collected objects.

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
---
 EightBit/BigEndianProcessor.cs    | 32 ++++++++++++++++---------------
 EightBit/LittleEndianProcessor.cs | 32 ++++++++++++++++---------------
 2 files changed, 34 insertions(+), 30 deletions(-)

diff --git a/EightBit/BigEndianProcessor.cs b/EightBit/BigEndianProcessor.cs
index de3be89..0fd5766 100644
--- a/EightBit/BigEndianProcessor.cs
+++ b/EightBit/BigEndianProcessor.cs
@@ -5,6 +5,8 @@ namespace EightBit
 {
     public abstract class BigEndianProcessor : Processor
     {
+        private readonly Register16 intermediate = new Register16();
+
         protected BigEndianProcessor(Bus memory)
         : base(memory)
         {
@@ -12,9 +14,9 @@ namespace EightBit
 
         public override Register16 PeekWord(ushort address)
         {
-            var high = this.Bus.Peek(address);
-            var low = this.Bus.Peek(++address);
-            return new Register16(low, high);
+            this.intermediate.High = this.Bus.Peek(address);
+            this.intermediate.Low = this.Bus.Peek(++address);
+            return this.intermediate;
         }
 
         public override void PokeWord(ushort address, Register16 value)
@@ -25,31 +27,31 @@ namespace EightBit
 
         protected override Register16 FetchWord()
         {
-            var high = this.FetchByte();
-            var low = this.FetchByte();
-            return new Register16(low, high);
+            this.intermediate.High = this.FetchByte();
+            this.intermediate.Low = this.FetchByte();
+            return this.intermediate;
         }
 
         protected override Register16 GetWord()
         {
-            var high = this.BusRead();
+            this.intermediate.High = this.BusRead();
             ++this.Bus.Address.Word;
-            var low = this.BusRead();
-            return new Register16(low, high);
+            this.intermediate.Low = this.BusRead();
+            return this.intermediate;
         }
 
         protected override Register16 GetWordPaged(byte page, byte offset)
         {
-            var high = this.BusRead(offset, page);
-            var low = this.BusRead(++offset, page);
-            return new Register16(low, high);
+            this.intermediate.High = this.BusRead(offset, page);
+            this.intermediate.Low = this.BusRead(++offset, page);
+            return this.intermediate;
         }
 
         protected override Register16 PopWord()
         {
-            var high = this.Pop();
-            var low = this.Pop();
-            return new Register16(low, high);
+            this.intermediate.High = this.Pop();
+            this.intermediate.Low = this.Pop();
+            return this.intermediate;
         }
 
         protected override void PushWord(Register16 value)
diff --git a/EightBit/LittleEndianProcessor.cs b/EightBit/LittleEndianProcessor.cs
index f8e9f38..c8a68ce 100644
--- a/EightBit/LittleEndianProcessor.cs
+++ b/EightBit/LittleEndianProcessor.cs
@@ -6,6 +6,8 @@ namespace EightBit
 {
     public abstract class LittleEndianProcessor : Processor
     {
+        private readonly Register16 intermediate = new Register16();
+
         protected LittleEndianProcessor(Bus memory)
         : base(memory)
         {
@@ -13,9 +15,9 @@ namespace EightBit
 
         public override Register16 PeekWord(ushort address)
         {
-            var low = this.Bus.Peek(address);
-            var high = this.Bus.Peek(++address);
-            return new Register16(low, high);
+            this.intermediate.Low = this.Bus.Peek(address);
+            this.intermediate.High = this.Bus.Peek(++address);
+            return this.intermediate;
         }
 
         public override void PokeWord(ushort address, Register16 value)
@@ -26,31 +28,31 @@ namespace EightBit
 
         protected override Register16 FetchWord()
         {
-            var low = this.FetchByte();
-            var high = this.FetchByte();
-            return new Register16(low, high);
+            this.intermediate.Low = this.FetchByte();
+            this.intermediate.High = this.FetchByte();
+            return this.intermediate;
         }
 
         protected override Register16 GetWord()
         {
-            var low = this.BusRead();
+            this.intermediate.Low = this.BusRead();
             ++this.Bus.Address.Word;
-            var high = this.BusRead();
-            return new Register16(low, high);
+            this.intermediate.High = this.BusRead();
+            return this.intermediate;
         }
 
         protected override Register16 GetWordPaged(byte page, byte offset)
         {
-            var low = this.BusRead(offset, page);
-            var high = this.BusRead(++offset, page);
-            return new Register16(low, high);
+            this.intermediate.Low = this.BusRead(offset, page);
+            this.intermediate.High = this.BusRead(++offset, page);
+            return this.intermediate;
         }
 
         protected override Register16 PopWord()
         {
-            var low = this.Pop();
-            var high = this.Pop();
-            return new Register16(low, high);
+            this.intermediate.Low = this.Pop();
+            this.intermediate.High = this.Pop();
+            return this.intermediate;
         }
 
         protected override void PushWord(Register16 value)