implemented bcfInstruction

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#24

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(0x0694));
+        program.add(CommandDecoder.decode(0x1114));
         for(int i = 0; i < program.size(); i++)
         {
             program.get(ProgramCounter.getPc()).execute();

de/darkress/pic16f84sim/commands/Bcf.java

@@ -0,0 +1,26 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+import de.darkress.pic16f84sim.microcontroller.ProgramCounter;
+
+public class Bcf extends BitOrientedCommandUtils implements Command
+{
+    private final int address;
+    private int bitPlacement;
+
+    public Bcf(int input)
+    {
+        address = input & 0x007F;
+        bitPlacement = checkBitPlacement(input);
+    }
+
+    @Override
+    public void execute()
+    {
+        int result = Memory.getRegister(address);
+        result &= ~(1 << bitPlacement); //Mask n-th bit with 0
+
+        Memory.setRegister(address, result);
+        ProgramCounter.incPC();
+    }
+}

de/darkress/pic16f84sim/commands/BitOrientedCommandUtils.java

@@ -0,0 +1,11 @@
+package de.darkress.pic16f84sim.commands;
+
+import de.darkress.pic16f84sim.microcontroller.Memory;
+
+public class BitOrientedCommandUtils
+{
+    protected int checkBitPlacement(int input)
+    {
+        return ((input & 0x0380) >>7);
+    }
+}

de/darkress/pic16f84sim/decoder/CommandDecoder.java

@@ -57,8 +57,7 @@ public class CommandDecoder
         switch(input & 0x3C00)
         {
             case 0x1000:
-                //bcf();
-                break;
+                return new Bcf(input);
             case 0x1400:
                 //bsf();
                 break;