implemented btfsc Instruction (#27)

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#27

de/darkress/pic16f84sim/Main.java

@@ -14,7 +14,7 @@ class Main
         ArrayList<Command> program = new ArrayList<>();
         Memory.workingRegister = 0x01;
         Memory.setRegister(0x14, 0xA5); //240 << 224
-        program.add(CommandDecoder.decode(0x1594));
+        program.add(CommandDecoder.decode(0x1894));
         for(int i = 0; i < program.size(); i++)
         {
             program.get(ProgramCounter.getPc()).execute();

de/darkress/pic16f84sim/commands/Btfsc.java

@@ -0,0 +1,29 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+
+public class Btfsc extends BitOrientedCommandUtils implements Command
+{
+    private final int address;
+    private int bitPlacement;
+
+    public Btfsc(int input)
+    {
+        address = input & 0x007F;
+        bitPlacement = checkBitPlacement(input);
+    }
+
+    @Override
+    public void execute()
+    {
+        int result = Memory.getRegister(address);
+
+        if((result & (1 << bitPlacement)) == 0) //Test if bit is clear
+        {
+            ProgramCounter.incPC();
+        }
+
+        ProgramCounter.incPC();
+    }
+}

de/darkress/pic16f84sim/decoder/CommandDecoder.java

@@ -61,8 +61,7 @@ public class CommandDecoder
             case 0x1400:
                 return new Bsf(input);
             case 0x1800:
-                //btfsc();
+                return new Btfsc(input);
-                break;
             case 0x1C00:
                 //btfss();
                 break;