Tidy register increment/decrement a little.

EightBit/BigEndianProcessor.cs

@@ -28,7 +28,7 @@ namespace EightBit
         protected override Register16 GetWord()
         {
             this.Intermediate.High = this.MemoryRead();
-            this.Bus.Address.Increment();
+            _ = this.Bus.Address.Increment();
             this.Intermediate.Low = this.MemoryRead();
             return this.Intermediate;
         }
@@ -57,7 +57,7 @@ namespace EightBit
         protected override void SetWord(Register16 value)
         {
             this.MemoryWrite(value.High);
-            this.Bus.Address.Increment();
+            _ = this.Bus.Address.Increment();
             this.MemoryWrite(value.Low);
         }
 

EightBit/IntelProcessor.cs

@@ -100,12 +100,13 @@ namespace EightBit
 
         protected abstract void EnableInterrupts();
 
-        protected override void IncrementPC()
+        protected override Register16 IncrementPC()
         {
             if (this.HALT.Raised())
             {
-                base.IncrementPC();
+                return base.IncrementPC();
             }
+            return this.PC;
         }
 
         protected override byte FetchInstruction()
@@ -149,14 +150,13 @@ namespace EightBit
 
         protected sealed override void Push(byte value)
         {
-            this.SP.Decrement();
-            this.MemoryWrite(this.SP, value);
+            this.MemoryWrite(this.SP.Decrement(), value);
         }
 
         protected sealed override byte Pop()
         {
             var returned = this.MemoryRead(this.SP);
-            this.SP.Increment();
+            _ = this.SP.Increment();
             return returned;
         }
 

EightBit/LittleEndianProcessor.cs

@@ -29,7 +29,7 @@ namespace EightBit
         protected override Register16 GetWord()
         {
             this.Intermediate.Low = this.MemoryRead();
-            this.Bus.Address.Increment();
+            _ = this.Bus.Address.Increment();
             this.Intermediate.High = this.MemoryRead();
             return this.Intermediate;
         }
@@ -58,7 +58,7 @@ namespace EightBit
         protected override void SetWord(Register16 value)
         {
             this.MemoryWrite(value.Low);
-            this.Bus.Address.Increment();
+            _ = this.Bus.Address.Increment();
             this.MemoryWrite(value.High);
         }
 

EightBit/Processor.cs

@@ -261,14 +261,14 @@ namespace EightBit
 
         protected virtual byte BusRead() => this.Bus.Read();   // N.B. Should be the only real call into the "Bus.Read" code.
 
-        protected virtual void IncrementPC() => this.PC.Increment();
+        protected virtual Register16 IncrementPC() => this.PC.Increment();
 
-        protected virtual void DecrementPC() => this.PC.Decrement();
+        protected virtual Register16 DecrementPC() => this.PC.Decrement();
 
         protected virtual void ImmediateAddress()
         {
             this.Bus.Address.Assign(this.PC);
-            this.IncrementPC();
+            _ = this.IncrementPC();
         }
 
         protected virtual byte FetchByte()

EightBit/Register16.cs

@@ -95,14 +95,14 @@ namespace EightBit
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public Register16 Increment()
         {
-            this.Word++;
+            ++this.Word;
             return this;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public Register16 Decrement()
         {
-            this.Word--;
+            --this.Word;
             return this;
         }
     }