implemented Retlw instruction

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#4

de/darkress/pic16f84sim/commands/Retlw.java

@@ -0,0 +1,24 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+import de.darkress.pic16f84sim.microcontroller.Stack;
+
+public class Retlw extends CommandUtils implements Command
+{
+    private final int literal;
+
+    public Retlw(int input)
+    {
+        literal = input & 0x00FF;
+    }
+
+    @Override
+    public void execute()
+    {
+        Memory.workingRegister = literal;
+        ProgramCounter.setPcFrom11BitLiteral(Stack.pop());
+        //TODO: This may need some rework since it does not really load all 13 Bit into the PC. Only 8 Bit are
+        // effectively set
+    }
+}

de/darkress/pic16f84sim/commands/Return.java

@@ -9,5 +9,7 @@ public class Return extends CommandUtils implements Command
     public void execute()
     {
         ProgramCounter.setPcFrom11BitLiteral(Stack.pop());
+        //TODO: This may need some rework since it does not really load all 13 Bit into the PC. Only 8 Bit are
+        // effectively set
     }
 }

de/darkress/pic16f84sim/decoder/CommandDecoder.java

@@ -110,8 +110,7 @@ public class CommandDecoder
             case 0x3000:
                 return new Movlw(input);
             case 0x3400:
-                //retlw();
-                break;
+                return new Retlw(input);
         }
 
         if ((input | 0x0060) == 0x0060)