Make "Pop" more like "Read". i.e. don't return a result, just use the value placed on the "bus"

EightBit/BigEndianProcessor.cs

@@ -51,8 +51,10 @@ namespace EightBit
         protected override void PopInto(Register16 into)
         {
             //ArgumentNullException.ThrowIfNull(into);
-            into.High = this.Pop();
-            into.Low = this.Pop();
+            this.Pop();
+            into.High = this.Bus.Data;
+            this.Pop();
+            into.Low = this.Bus.Data;
         }
 
         protected override void PushShort(Register16 value)

EightBit/IntelProcessor.cs

@@ -148,11 +148,10 @@ namespace EightBit
             this.MemoryWrite(this.SP, value);
         }
 
-        protected sealed override byte Pop()
+        protected sealed override void Pop()
         {
             this.MemoryRead(this.SP);
             this.SP.Increment();
-            return this.Bus.Data;
         }
 
         protected sealed override void GetShort()

EightBit/LittleEndianProcessor.cs

@@ -52,8 +52,10 @@ namespace EightBit
         protected override void PopInto(Register16 into)
         {
             //ArgumentNullException.ThrowIfNull(into);
-            into.Low = this.Pop();
-            into.High = this.Pop();
+            this.Pop();
+            into.Low = this.Bus.Data;
+            this.Pop();
+            into.High = this.Bus.Data;
         }
 
         protected override void PushShort(Register16 value)

EightBit/Processor.cs

@@ -267,7 +267,7 @@ namespace EightBit
 
         protected abstract void Push(byte value);
 
-        protected abstract byte Pop();
+        protected abstract void Pop();
 
         protected abstract void PushShort(Register16 value);