diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..62c8935
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.idea/
\ No newline at end of file
diff --git a/cmd/root.go b/cmd/root.go
index ec01c6d..8167a53 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -24,8 +24,10 @@ var rootCommand = &cobra.Command{
 	RunE: runRootCommand,
 }
 
+var debug bool
+
 func init() {
-	rootCommand.Flags().BoolP("debug", "d", false, "Enable debug mode")
+	rootCommand.Flags().BoolVarP(&debug, "debug", "d", false, "Enable debug mode")
 }
 
 func runRootCommand(cmd *cobra.Command, args []string) error {
@@ -50,7 +52,7 @@ func runRootCommand(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
-	module, err := hal.NewHALModule(program, 256, 2)
+	module, err := hal.NewHALModule(program, 256, 2, debug)
 	if err != nil {
 		return err
 	}
diff --git a/hal/instructions.go b/hal/instructions.go
index 4aa198e..c637348 100644
--- a/hal/instructions.go
+++ b/hal/instructions.go
@@ -12,6 +12,7 @@ type ProgrammedInstruction struct {
 
 func (pi *ProgrammedInstruction) Execute(module *Module) error {
 	if pi.Instruction.ExecuteWithOperand != nil {
+		module.debug("Operand: %d", pi.Operand)
 		return pi.Instruction.ExecuteWithOperand(module, pi.Operand)
 	} else if pi.Instruction.Execute != nil {
 		return pi.Instruction.Execute(module)
@@ -40,6 +41,7 @@ var instructions = []*Instruction{
 	InstructionStop,
 	InstructionIn,
 	InstructionOut,
+	InstructionAddnum,
 }
 
 var InstructionStart = &Instruction{
@@ -128,3 +130,10 @@ var InstructionJumpNeg = &Instruction{
 		return nil
 	},
 }
+
+var InstructionAddnum = &Instruction{
+	Name: "ADDNUM",
+	ExecuteWithOperand: func(module *Module, operand float64) {
+		module.accumulator = module.accumulator + operand
+	},
+}
diff --git a/hal/module.go b/hal/module.go
index f8597d4..fbf4532 100644
--- a/hal/module.go
+++ b/hal/module.go
@@ -11,7 +11,9 @@ type Module struct {
 	programStorage Program
 	register       []float64
 	IO             []float64
-	isStopped      bool
+
+	isStopped    bool
+	debugEnabled bool
 }
 
 func (h *Module) programCounter() int64 {
@@ -29,13 +31,23 @@ func (h *Module) increaseProgramCounter() {
 	h.register[0]++
 }
 
+func (h *Module) debug(format string, args ...interface{}) {
+	if !h.debugEnabled {
+		return
+	}
+	fmt.Printf("[DEBUG] "+format+"\n", args...)
+}
+
 func (h *Module) Step() {
 	instruction := h.programStorage[h.programCounter()]
 	h.increaseProgramCounter()
 	if instruction == nil {
 		return
 	}
+	h.debug("Instruction: %s", instruction.Instruction.Name)
+	h.debug("Accumulator before: %f", h.accumulator)
 	instruction.Execute(h)
+	h.debug("Accumulator after: %f", h.accumulator)
 }
 
 func (h *Module) Run() error {
@@ -48,7 +60,7 @@ func (h *Module) Run() error {
 	return nil
 }
 
-func NewHALModule(program Program, registerSize uint64, ioSize uint64) (*Module, error) {
+func NewHALModule(program Program, registerSize uint64, ioSize uint64, debug bool) (*Module, error) {
 	if registerSize <= 10 {
 		return nil, fmt.Errorf("register size must be greater then 10 [ registerSize = %d ]", registerSize)
 	}
@@ -56,5 +68,6 @@ func NewHALModule(program Program, registerSize uint64, ioSize uint64) (*Module,
 		programStorage: program,
 		register:       make([]float64, registerSize),
 		IO:             make([]float64, ioSize),
+		debugEnabled:   debug,
 	}, nil
 }