diff --git a/cmd/root.go b/cmd/root.go
index b732288..846886c 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 {
@@ -50,6 +52,6 @@ func runRootCommand(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
-	hal.NewHALModule(program, 256)
+	hal.NewHALModule(program, 256, debug)
 	return nil
 }
diff --git a/hal/instructions.go b/hal/instructions.go
index ceed661..043c272 100644
--- a/hal/instructions.go
+++ b/hal/instructions.go
@@ -11,6 +11,7 @@ type ProgrammedInstruction struct {
 
 func (pi *ProgrammedInstruction) Execute(module *Module) {
 	if pi.Instruction.ExecuteWithOperand != nil {
+		module.debug("Operand: %d", pi.Operand)
 		pi.Instruction.ExecuteWithOperand(module, pi.Operand)
 	} else if pi.Instruction.Execute != nil {
 		pi.Instruction.Execute(module)
diff --git a/hal/module.go b/hal/module.go
index 09ded49..d4b4779 100644
--- a/hal/module.go
+++ b/hal/module.go
@@ -10,7 +10,9 @@ type Module struct {
 	Accumulator    float64
 	ProgramStorage Program
 	Register       []float64
-	isStopped      bool
+
+	isStopped    bool
+	debugEnabled bool
 }
 
 func (h *Module) ProgramCounter() int64 {
@@ -21,13 +23,23 @@ func (h *Module) increaseProgramCounter() {
 	h.Register[0]++
 }
 
+func (h *Module) debug(format string, args ...interface{}) {
+	if !h.debugEnabled {
+		return
+	}
+	fmt.Printf("[DEBUG] "+format, 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: %d", h.Accumulator)
 	instruction.Execute(h)
+	h.debug("Accumulator after: %d", h.Accumulator)
 }
 
 func (h *Module) Run() error {
@@ -40,12 +52,13 @@ func (h *Module) Run() error {
 	return nil
 }
 
-func NewHALModule(program Program, registerSize uint64) (*Module, error) {
+func NewHALModule(program Program, registerSize uint64, debug bool) (*Module, error) {
 	if registerSize <= 10 {
 		return nil, fmt.Errorf("register size must be greater then 10 [ registerSize = %d ]", registerSize)
 	}
 	return &Module{
 		ProgramStorage: program,
 		Register:       make([]float64, registerSize),
+		debugEnabled:   debug,
 	}, nil
 }