diff --git a/sim/atomsim.cpp b/sim/atomsim.cpp
index 0aa114a..2445c37 100755
--- a/sim/atomsim.cpp
+++ b/sim/atomsim.cpp
@@ -39,6 +39,8 @@ void Atomsim::step()
 
 int Atomsim::run()
 {   
+    int exitcode=EXIT_SUCCESS;
+
     // tick backend and update backend status, until ctrl+c is.
     try
     {
@@ -49,9 +51,10 @@ int Atomsim::run()
         in_debug_mode_ = sim_config_.debug_flag;
 
         pending_steps = 0;
+
+        init_interactive_mode();
         
         // *** Simulation Loop ***
-        Rcode rval = RC_NONE;
         while (bkend_running_)
         {
             // Refresh state
@@ -94,18 +97,21 @@ int Atomsim::run()
                     pending_steps = 0;
                 } else {
                     printf("Exiting..\n");
-                    return 0;
+                    exitcode = EXIT_SUCCESS;
+                    break;
                 }
             }
 
             // check sim iterations
             if(simstate_.state_.tickcount_total > sim_config_.maxitr) {
                 throwError("SIM0", "Simulation iterations exceeded maxitr("+std::to_string(sim_config_.maxitr)+")\n");
-                return 1;
+                exitcode = EXIT_FAILURE;
+                break;
             }
             
             // Enter interactive mode if we aren's stepping and we are already in debug mode or run mode
             // was interrupted by user (CTRL_C)
+            Rcode rval;
             if((pending_steps == 0) && (in_debug_mode_ || CTRL_C_PRESSED)) {
                 // explictly set: since we can also enter if CTRL_C_PRESSED
                 in_debug_mode_ = true;
@@ -125,6 +131,7 @@ int Atomsim::run()
                     CTRL_C_PRESSED = false;
                 } else if (rval == RC_EXIT) {
                     // Exit sim
+                    exitcode = EXIT_SUCCESS;
                     break;
                 }
             }
@@ -143,5 +150,9 @@ int Atomsim::run()
         std::cerr << "Runtime exception: " << e.what() << std::endl;
         return 1;
     }
-    return 0;
+
+    // Exiting sim
+    deinit_interactive_mode();
+
+    return exitcode;
 }
diff --git a/sim/atomsim.hpp b/sim/atomsim.hpp
index 7e4ce3c..9640d73 100755
--- a/sim/atomsim.hpp
+++ b/sim/atomsim.hpp
@@ -60,10 +60,6 @@ class Atomsim
      */
     Atomsim(Atomsim_config sim_config, Backend_config bk_config);
 
-    /**
-     * @brief step simulation by a cycle
-     */
-    void step();
 
     /**
      * @brief run simulation until finished
@@ -71,14 +67,6 @@ class Atomsim
      */
     int run();
 
-    /**
-     * @brief enter interactive mode
-     * 
-     * @returns int return code [if 2: exit sim]
-     */
-    Rcode run_interactive_mode();
-        
-
 private:
     /**
      * @brief config struct object for sim
@@ -130,6 +118,27 @@ class Atomsim
     // used to provide cycles for step command
     long long pending_steps = 0;
 
+    /**
+     * @brief step simulation by a cycle
+     */
+    void step();
+
+    /**
+     * @brief initialize interactive mode
+    */
+    void init_interactive_mode();
+
+    /**
+     * @brief Deinitialize interactive mode
+    */
+    void deinit_interactive_mode();
+
+    /**
+     * @brief enter interactive mode
+     */
+    Rcode run_interactive_mode();
+
+
     // display debug screen
     void display_dbg_screen();
 
diff --git a/sim/interactive.cpp b/sim/interactive.cpp
index 03bb7e5..cf1550b 100755
--- a/sim/interactive.cpp
+++ b/sim/interactive.cpp
@@ -18,6 +18,7 @@
 #define DEFAULT_TRACEFILE_PATH "trace.vcd"
 #define ATOMSIM_PROMPT "atomsim> "
 #define ATOMSIM_HISTORY_FILE ".atomsim_history"
+#define ATOMSIM_HISTORY_LENGTH 1000
 
 
 void Atomsim::display_dbg_screen()
@@ -157,6 +158,24 @@ void _hexdump(const unsigned char *buf, size_t bufsz, uint32_t base_addr, bool e
     }
 }
 
+void Atomsim::init_interactive_mode(){
+    // init
+    using_history();
+
+    // Set history list length
+    stifle_history(ATOMSIM_HISTORY_LENGTH);
+
+    // read history file
+    read_history(ATOMSIM_HISTORY_FILE);
+}
+
+
+void Atomsim::deinit_interactive_mode(){
+    // write history file
+    write_history(ATOMSIM_HISTORY_FILE);
+}
+
+
 Rcode Atomsim::run_interactive_mode()
 {
     typedef Rcode (Atomsim::*interactive_func)(const std::vector<std::string>&);
@@ -188,18 +207,6 @@ Rcode Atomsim::run_interactive_mode()
     static std::string prev_cmd;
     static std::vector<std::string> prev_args;
 
-    // create history file if it doen't exist
-    FILE *history_file = fopen(ATOMSIM_HISTORY_FILE, "a");
-    if (history_file != NULL) {
-        fclose(history_file);
-    } else {
-        std::cerr << "Error creating history file.\n";
-        return RC_EXIT;
-    }
-
-    // read history file
-    read_history(ATOMSIM_HISTORY_FILE);
-
     while(!backend_.done())
     {
         // get input
@@ -231,8 +238,6 @@ Rcode Atomsim::run_interactive_mode()
         // Add input to history if it's != previous input
         if(cmd != prev_cmd){
             add_history(input.c_str());
-            // save to history file
-            write_history(ATOMSIM_HISTORY_FILE);
         }
 
         // prev <= current