diff --git a/src/main/java/fabrik/simulator/pic16f84/Commands.java b/src/main/java/fabrik/simulator/pic16f84/Commands.java
index b0e9c66..a0ef629 100644
--- a/src/main/java/fabrik/simulator/pic16f84/Commands.java
+++ b/src/main/java/fabrik/simulator/pic16f84/Commands.java
@@ -8,11 +8,11 @@ public class Commands {
     }
 
     public static void decode(int instruction){
-        int jumpaddr = 0x7FF;
-        int fileregaddr = 0x7F;
-        int constant = 0xFF;
-        int bitaddr = 0x380;
-        int destinationbit = 0x80;
+        final int jumpaddr = 0x7FF;
+        final int fileregaddr = 0x7F;
+        final int constant = 0xFF;
+        final int bitaddr = 0x380;
+        final int destinationbit = 0x80;
 
         int d = (instruction & destinationbit) >> 7;
         int f = instruction & fileregaddr;
@@ -116,6 +116,10 @@ public class Commands {
                 System.out.println("RLF: " + f + " " + d);
                 RLF (f, d);
                 return;
+            case 0b00110000000000:
+                System.out.println("RRF: " + f + " " + d);
+                RRF (f, d);
+                return;
             case 0b00001000000000:
                 System.out.println("SUBWF: " + f + " " + d);
                 SUBWF (f, d);
@@ -168,11 +172,11 @@ public class Commands {
                 return;
             case 0b1001:
                 System.out.println("RETFIE");
-                //TODO
+                RETFIE();
                 return;
             case 0b1000:
                 System.out.println("RETURN");
-                //TODO
+                DataRegister.setPC(ProgramStack.pop());
                 return;
             case 0b01100011:
                 System.out.println("SLEEP");
@@ -192,12 +196,17 @@ public class Commands {
 
     }
 
+    public static void RETFIE() {
+        DataRegister.setPC(ProgramStack.pop());
+    }
+
     public static void GOTO(int jump) {
         DataRegister.setPC(jump-1);
     }
 
     public static void CALL(int jump) {
-        //TODO
+        ProgramStack.push(DataRegister.getPC()+1);
+        DataRegister.setPC(jump-1);
     }
 
     public static void MOVWF(int file) {
@@ -206,27 +215,27 @@ public class Commands {
 
     public static void CLRW() {
         wRegister = 0;
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(wRegister);
     }
 
     public static void CLRF(int file) {
         DataRegister.setRegister(file, 0);
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(DataRegister.getRegister(file));
     }
 
     public static void IORLW(int literal) {
         wRegister |= literal;
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(wRegister);
     }
 
     public static void XORLW(int literal) {
         wRegister ^= literal;
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(wRegister);
     }
 
     public static void ANDLW(int literal) {
         wRegister &= literal;
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(wRegister);
     }
 
     public static void XORWF(int file, int destination) {
@@ -237,7 +246,7 @@ public class Commands {
         else {
             DataRegister.setRegister(file, result);
         }
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void SWAPF(int file, int destination) {
@@ -252,18 +261,49 @@ public class Commands {
     }
 
     public static void SUBWF(int file, int destination) {
-        int result = (DataRegister.getRegister(file) - wRegister) & 0xFF;
-        if (destination == 0){
-            wRegister = result;
+        int result = (DataRegister.getRegister(file) - wRegister) ;
+        if (wRegister == 0 || result >= 0){
+            DataRegister.setCarryFlag(1);
+            DataRegister.setDigitCarryFlag(1);
         }
         else {
-            DataRegister.setRegister(file, result);
+            DataRegister.setCarryFlag(0);
+            DataRegister.setDigitCarryFlag(0);
         }
-        // TODO Zeroflag, Carry, DigitCarry
+        if (destination == 0){
+            wRegister = result & 0xFF;
+        }
+        else {
+            DataRegister.setRegister(file, result & 0xFF);
+        }
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void RLF(int file, int destination) {
-        // TODO
+        int fcontent = DataRegister.getRegister(file);
+        int carry = DataRegister.getCarryFlag();
+        int result = (fcontent << 1) | carry;
+        DataRegister.determineCarryFlag(result);
+        if (destination == 0){
+            wRegister = result & 0xFF;
+        }
+        else {
+            DataRegister.setRegister(file, result & 0xFF);
+        }
+    }
+
+    public static void RRF(int file, int destination) {
+        int fcontent = DataRegister.getRegister(file);
+        int carry = DataRegister.getCarryFlag() << 7;
+        int contentlow = fcontent & 0b1;
+        int result = fcontent >> 1 | carry;
+        DataRegister.setCarryFlag(contentlow);
+        if (destination == 0){
+            wRegister = result & 0xFF;
+        }
+        else {
+            DataRegister.setRegister(file, result & 0xFF);
+        }
     }
 
     public static void MOVF(int file, int destination) {
@@ -274,7 +314,7 @@ public class Commands {
         else {
             DataRegister.setRegister(file, content);
         }
-        // TODO: Zeroflag
+        DataRegister.determineZeroFlag(content);
     }
 
     public static void IORWF(int file, int destination) {
@@ -285,7 +325,7 @@ public class Commands {
         else {
             DataRegister.setRegister(file, result);
         }
-        // TODO: Zeroflag
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void INCFSZ(int file, int destination) {
@@ -309,7 +349,7 @@ public class Commands {
         else {
             DataRegister.setRegister(file, result);
         }
-        //TODO: Zeroflag
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void DECFSZ(int file, int destination) {
@@ -333,7 +373,7 @@ public class Commands {
         else {
             DataRegister.setRegister(file, result);
         }
-        // TODO: Zeroflag
+        DataRegister.determineZeroFlag(result);
     }
 
     private static void COMF(int file, int destination) {
@@ -344,44 +384,67 @@ public class Commands {
         else {
             DataRegister.setRegister(file, result);
         }
-        // TODO: Zeroflag
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void ANDWF(int file, int destination) {
         int result = wRegister & DataRegister.getRegister(file);
         if (destination == 0){
-            wRegister = result;
+            wRegister = result & 0xFF;
         }
         else {
-            DataRegister.setRegister(file, result);
+            DataRegister.setRegister(file, result & 0xFF);
         }
-        // TODO: Zeroflag, Carry, DigitCarry
+        DataRegister.determineZeroFlag(result);
+        DataRegister.determineCarryFlag(result);
+        DataRegister.determineDigitCarryFlag(result);
     }
 
     public static void ADDWF(int file, int destination) {
         int result = wRegister + DataRegister.getRegister(file);
-        if (destination == 0) {
-            wRegister = result;
+        if (wRegister == 0 || DataRegister.getRegister(file) == 0){
+            DataRegister.setCarryFlag(0);
+            DataRegister.setDigitCarryFlag(0);
         }
         else {
-            DataRegister.setRegister(file, result);
+            DataRegister.determineCarryFlag(result);
+            DataRegister.determineDigitCarryFlag(result);
         }
-        // TODO: Zeroflag, Carry, DigitCarry
+        if (destination == 0) {
+            wRegister = result & 0xFF;
+        }
+        else {
+            DataRegister.setRegister(file, result & 0xFF);
+        }
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void SUBLW(int literal) {
-        wRegister = literal - wRegister;
-        // TODO: Zeroflag, Carry, DigitCarry
+        int result = literal - wRegister;
+        if (wRegister == 0 || result >= 0){
+            DataRegister.setCarryFlag(1);
+            DataRegister.setDigitCarryFlag(1);
+        }
+        else {
+
+            DataRegister.setCarryFlag(0);
+            DataRegister.setDigitCarryFlag(0);
+        }
+        wRegister = result & 0xFF;
+        DataRegister.determineZeroFlag(result);
     }
 
     public static void ADDLW(int literal) {
-        wRegister += literal;
-        // TODO: Zeroflag, Carry, DigitCarry
+        int result = wRegister + literal;
+        wRegister = result & 0xFF;
+        DataRegister.determineZeroFlag(result);
+        DataRegister.determineCarryFlag(result);
+        DataRegister.determineDigitCarryFlag(result);
     }
 
     public static void RETLW(int literal) {
         wRegister = literal;
-        //TODO: PC vom Stack holen und laden
+        DataRegister.setPC(ProgramStack.pop());
     }
 
     public static void MOVLW(int literal) {
diff --git a/src/main/java/fabrik/simulator/pic16f84/Controller_FileSelect.java b/src/main/java/fabrik/simulator/pic16f84/Controller_FileSelect.java
index eb9724f..6981b54 100644
--- a/src/main/java/fabrik/simulator/pic16f84/Controller_FileSelect.java
+++ b/src/main/java/fabrik/simulator/pic16f84/Controller_FileSelect.java
@@ -42,6 +42,9 @@ public class Controller_FileSelect {
                     Commands.decode(prog[DataRegister.getPC()]);
                     System.out.println("\nPC: " + DataRegister.getPC());
                     System.out.println("W: " + Commands.get_wRegister());
+                    System.out.println("C: " + DataRegister.getCarryFlag());
+                    System.out.println("DC: " + DataRegister.getDigitCarryFlag());
+                    System.out.println(ProgramStack.getStack());
                     System.out.printf(Arrays.toString(DataRegister.getDataRegister()));
                     DataRegister.increasePC();
                 }
diff --git a/src/main/java/fabrik/simulator/pic16f84/DataRegister.java b/src/main/java/fabrik/simulator/pic16f84/DataRegister.java
index 619a638..c01fbc9 100644
--- a/src/main/java/fabrik/simulator/pic16f84/DataRegister.java
+++ b/src/main/java/fabrik/simulator/pic16f84/DataRegister.java
@@ -3,30 +3,49 @@ package fabrik.simulator.pic16f84;
 import java.util.Arrays;
 
 public class DataRegister {
-    public static final int STATUS = 0x3;
-    public static final int TRISA = 0x85;
-    public static final int TRISB = 0x86;
-    public static final int PCL = 0x2;
-    public static final int RP0 = 0x5;
+    private static final int PCL = 0x2;
+    private static final int STATUS = 0x3;
+    private static final int FSR = 0x4;
+    private static final int PCLATH = 0xA;
+    private static final int INTCON = 0xB;
+
+    private static final int TRISA = 0x85;
+    private static final int TRISB = 0x86;
+
+    private static final int C = 0x0;
+    private static final int DC = 0x1;
+    private static final int Z = 0x2;
+    private static final int RP0 = 0x5;
+
 
     private static final int [] dataRegister =  new int[0xFF];
+    private static final int [] syncedRegisters = {PCL, STATUS, FSR, PCLATH, INTCON};
 
     public static void initDataRegister() {
         dataRegister[PCL] = 0b0;
         dataRegister[STATUS] = 0b00011000;
-        dataRegister[0xA] = 0b0;
-        dataRegister[0xB] = 0b0;
+        dataRegister[PCLATH] = 0b0;
+        dataRegister[INTCON] = 0b0;
 
         dataRegister[0x81] = 0b11111111;
-        dataRegister[0x82] = dataRegister[PCL];
-        dataRegister[0x83] = dataRegister[STATUS];
+        dataRegister[0x80 + PCL] = dataRegister[PCL];
+        dataRegister[0x80 + STATUS] = dataRegister[STATUS];
         dataRegister[TRISA] = 0b11111000;
         dataRegister[TRISB] = 0b11111111;
-        dataRegister[0x8A] = dataRegister[0xA];
-        dataRegister[0x8B] = dataRegister[0xB];
+        dataRegister[0x80 + PCLATH] = dataRegister[PCLATH];
+        dataRegister[0x80 + INTCON] = dataRegister[INTCON];
         System.out.println(Arrays.toString(dataRegister));
     }
 
+    private static boolean isSyncedRegister (int address){
+        for (int register : syncedRegisters){
+            if (address == register || address == 0x80 + register){
+                return true;
+            }
+        }
+        return false;
+    }
+
     public static int[] getDataRegister() {
         return dataRegister;
     }
@@ -40,22 +59,47 @@ public class DataRegister {
     }
 
     public static void setRegister(int fileAddress, int content){
-        dataRegister[bank() + fileAddress] = content;
+        if (!isSyncedRegister(fileAddress))
+            dataRegister[bank() + fileAddress] = content;
+        else {
+            dataRegister[fileAddress] = content;
+            dataRegister[0x80 + fileAddress] = content;
+        }
     }
 
     public static int getBit(int address, int bit) {
         return (dataRegister[bank() + address] >> bit) & 1;
     }
 
+    private static int getDirectBit(int address, int bit){
+        return (dataRegister[address] >> bit) & 1;
+    }
+
     public static void clearBit(int address, int bit) {
-        if (getBit(address, bit) == 1) {
-            dataRegister[bank() + address] -= (int) Math.pow(2, bit);
+        if (!isSyncedRegister(address)) {
+            if (getBit(address, bit) == 1) {
+                dataRegister[bank() + address] -= (int) Math.pow(2, bit);
+            }
+        }
+        else {
+            if (getBit(address, bit) == 1) {
+                dataRegister[address] -= (int) Math.pow(2, bit);
+                dataRegister[0x80 + address] = dataRegister[address];
+            }
         }
     }
 
     public static void setBit(int address, int bit) {
-        if (getBit(address, bit) == 0) {
-            dataRegister[bank() + address] += (int) Math.pow(2, bit);
+        if (!isSyncedRegister(address)) {
+            if (getBit(address, bit) == 0) {
+                dataRegister[bank() + address] += (int) Math.pow(2, bit);
+            }
+        }
+        else {
+            if (getBit(address, bit) == 0) {
+                dataRegister[address] += (int) Math.pow(2, bit);
+                dataRegister[0x80 + address] = dataRegister[address];
+            }
         }
     }
 
@@ -85,4 +129,86 @@ public class DataRegister {
     public static int getPC(){
         return programCounter;
     }
+
+    private static int zeroFlag = 0;
+
+    public static void determineZeroFlag(int result){
+        if (result == 0){
+            zeroFlag = 1;
+            if (getBit(STATUS, Z) == 0){
+                dataRegister[STATUS] += 0b100;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+        else {
+            zeroFlag = 0;
+            if (getBit(STATUS, Z) == 1){
+                dataRegister[STATUS] -= 0b100;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+    }
+
+    private static int carryFlag = 0;
+
+    public static void setCarryFlag(int value){
+        carryFlag = value;
+        if (value == 1){
+            if (getBit(STATUS, C) == 0){
+                dataRegister[STATUS] += 0b1;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+        else {
+            if (getBit(STATUS, C) == 1){
+                dataRegister[STATUS] -= 0b1;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+    }
+
+    public static void determineCarryFlag (int result){
+        if (result > 0xFF){
+            setCarryFlag(1);
+        }
+        else {
+            setCarryFlag(0);
+        }
+    }
+
+    public static int getCarryFlag (){
+        return carryFlag;
+    }
+
+    private static int digitCarryFlag = 0;
+
+    public static void setDigitCarryFlag(int value){
+        digitCarryFlag = value;
+        if (value == 1){
+            if (getBit(STATUS, DC) == 0){
+                dataRegister[STATUS] += 0b10;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+        else {
+            if (getBit(STATUS, DC) == 1){
+                dataRegister[STATUS] -= 0b10;
+                dataRegister[0x80 + STATUS] = dataRegister[STATUS];
+            }
+        }
+    }
+
+    public static void determineDigitCarryFlag(int result){
+        if (result > 0xF){
+            setDigitCarryFlag(1);
+        }
+        else {
+            setDigitCarryFlag(0);
+        }
+    }
+
+    public static int getDigitCarryFlag(){
+        return digitCarryFlag;
+    }
+
 }
diff --git a/src/main/java/fabrik/simulator/pic16f84/ProgramStack.java b/src/main/java/fabrik/simulator/pic16f84/ProgramStack.java
new file mode 100644
index 0000000..2797ffa
--- /dev/null
+++ b/src/main/java/fabrik/simulator/pic16f84/ProgramStack.java
@@ -0,0 +1,25 @@
+package fabrik.simulator.pic16f84;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+public class ProgramStack {
+    private static Deque<Integer> returnStack = new ArrayDeque<>();
+
+    public static void push(int value) {
+        if (returnStack.size() != 7)
+            returnStack.push(value);
+        else {
+            System.out.println("Stack overflow");
+        }
+
+    }
+
+    public static int pop() {
+        return returnStack.pop();
+    }
+
+    public static Deque<Integer> getStack() {
+        return returnStack;
+    }
+}