Added swapf Instruction

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#22

de/darkress/pic16f84sim/Main.java

@@ -13,8 +13,8 @@ class Main
 
         ArrayList<Command> program = new ArrayList<>();
         Memory.workingRegister = 0x01;
-        Memory.setRegister(0x14, 0x01); //240 << 224
+        Memory.setRegister(0x14, 0xA5); //240 << 224
-        program.add(CommandDecoder.decode(0x0294));
+        program.add(CommandDecoder.decode(0x0E94));
         for(int i = 0; i < program.size(); i++)
         {
             program.get(ProgramCounter.getPc()).execute();

de/darkress/pic16f84sim/commands/Decfsz.java

@@ -26,7 +26,7 @@ public class Decfsz extends FileRegisterCommandUtils implements Command
         if((result % 256) == 0)
         {
             Nop nop = new Nop();
-            nop.execute();
+            nop.execute(); // TODO: What happens if an interrupt gets triggered during the nop execution?
         }
         ProgramCounter.incPC();
     }

de/darkress/pic16f84sim/commands/Incfsz.java

@@ -26,7 +26,7 @@ public class Incfsz extends FileRegisterCommandUtils implements Command
         if((result % 256) == 0)
         {
             Nop nop = new Nop();
-            nop.execute();
+            nop.execute(); // TODO: What happens if an interrupt gets triggered during the nop execution?
         }
         ProgramCounter.incPC();
     }

de/darkress/pic16f84sim/commands/Swapf.java

@@ -0,0 +1,27 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+
+public class Swapf extends FileRegisterCommandUtils implements Command
+{
+    private final int address;
+    private final boolean destinationBit;
+
+    public Swapf(int input)
+    {
+        address = input & 0x007F;
+        destinationBit = checkDestinationBit(input);
+    }
+
+    @Override
+    public void execute()
+    {
+        int result = (Memory.getRegister(address) <<4) & 0xF0;
+        int tmp = Memory.getRegister(address) >>4;
+        result += tmp;
+
+        writeToDestination(destinationBit, address, result);
+        ProgramCounter.incPC();
+    }
+}

de/darkress/pic16f84sim/decoder/CommandDecoder.java

@@ -33,8 +33,7 @@ public class CommandDecoder
             case 0x200:
                 return new Subwf(input);
             case 0xE00:
-                //swapf();
+                return new Swapf(input);
-                break;
             case 0x600:
                 //xorwf();
                 break;