diff --git a/npc/csrc/Flow/main.cpp b/npc/csrc/Flow/main.cpp
index f2933b4..ea71189 100644
--- a/npc/csrc/Flow/main.cpp
+++ b/npc/csrc/Flow/main.cpp
@@ -49,8 +49,10 @@ vpiHandle pc = nullptr;
 namespace NPC {
 void npc_memcpy(paddr_t addr, void *buf, size_t sz, bool direction) {
   if (direction == TRM_FROM_MACHINE) {
-    memcpy(buf, static_cast<Memory<int, 128 * 1024> *>(pmem_get())->mem.data(),
-           sz);
+    memcpy(
+        buf,
+        static_cast<Memory<int, 128 * 1024> *>(pmem_get())->guest_to_host(addr),
+        sz);
   }
 };
 
diff --git a/npc/include/components.hpp b/npc/include/components.hpp
index 9b5f546..4f8c592 100644
--- a/npc/include/components.hpp
+++ b/npc/include/components.hpp
@@ -79,5 +79,8 @@ public:
     // printf("waddr: 0x%x\n", waddr);
     mem[addr_to_index((uint32_t)waddr)] = expand_bits(wmask) & wdata;
   }
+  void *guest_to_host(std::size_t addr) {
+    return mem.data() + addr_to_index(addr);
+  }
 };
 #endif
diff --git a/npc/include/trm_difftest.hpp b/npc/include/trm_difftest.hpp
index dc75c4d..dd2a93d 100644
--- a/npc/include/trm_difftest.hpp
+++ b/npc/include/trm_difftest.hpp
@@ -34,19 +34,29 @@ struct DifftestTrmInterface : public TrmInterface {
       fetch_state();
     };
     exec = [this](uint64_t n) {
-      while (n--) {
+      bool enable_disasm = true;
+      if (n > 30) {
+        enable_disasm = false;
+      }
 
+      while (n--) {
         word_t pc = this->ref.at("pc");
         word_t inst = this->ref.at(pc);
-        std::cout << d.disassemble(pc, (uint8_t *)&inst, WORD_BYTES)
-                  << std::endl;
+        if (enable_disasm)
+          std::cout << d.disassemble(pc, (uint8_t *)&inst, WORD_BYTES)
+                    << std::endl;
+        if (inst == 1048691) {
+          // ebreak
+          throw TrmRuntimeException(TrmRuntimeException::EBREAK, "ebreak");
+        }
         this->ref.exec(1);
         this->dut.exec(1);
         this->ref.fetch_state();
         this->dut.fetch_state();
         if (*(CPUState *)this->ref.cpu_state !=
             *(CPUState *)this->dut.cpu_state) {
-          throw std::runtime_error("Difftest failed");
+          throw TrmRuntimeException(TrmRuntimeException::DIFFTEST_FAILED,
+                                    "Difftest failed");
         }
       }
     };
diff --git a/npc/include/trm_interface.hpp b/npc/include/trm_interface.hpp
index 22a37cf..716745d 100644
--- a/npc/include/trm_interface.hpp
+++ b/npc/include/trm_interface.hpp
@@ -96,6 +96,21 @@ public:
   virtual void print(std::ostream &os) const = 0;
 };
 
+class TrmRuntimeException : public std::exception {
+private:
+  const char *msg_;
+  int code_;
+
+public:
+  enum { EBREAK, DIFFTEST_FAILED };
+  TrmRuntimeException(int code, const char *message)
+      : code_(code), msg_(message) {}
+
+  virtual const char *what() const throw() { return msg_; }
+
+  int error_code() const { return code_; }
+};
+
 struct RefTrmInterface : TrmInterface {
   RefTrmInterface(std::filesystem::path lib_file) {
     void *handle = dlopen(lib_file.c_str(), RTLD_LAZY);
diff --git a/npc/utils/sdb/console.cpp b/npc/utils/sdb/console.cpp
index 485e192..61c9452 100644
--- a/npc/utils/sdb/console.cpp
+++ b/npc/utils/sdb/console.cpp
@@ -83,6 +83,12 @@ void Console::registerCommand(const std::string &s, CommandFunction f) {
   pimpl_->commands_[s] = f;
 }
 
+void Console::removeCommands(const std::vector<std::string> sv) {
+  for (auto const &s : sv) {
+    pimpl_->commands_.erase(s);
+  }
+}
+
 std::vector<std::string> Console::getRegisteredCommands() const {
   std::vector<std::string> allCommands;
   for (auto &pair : pimpl_->commands_)
diff --git a/npc/utils/sdb/include/console.hpp b/npc/utils/sdb/include/console.hpp
index 538ce2f..69c4099 100644
--- a/npc/utils/sdb/include/console.hpp
+++ b/npc/utils/sdb/include/console.hpp
@@ -64,6 +64,13 @@ public:
     */
   void registerCommand(const std::string &s, CommandFunction f);
 
+  /**
+    * @brief This function removes a list of registered commands.
+    *
+    * @param sv The vector of command names to be removed.
+    */
+  void removeCommands(const std::vector<std::string> sv);
+
   /**
     * @brief This function returns a list with the currently available commands.
     *
diff --git a/npc/utils/sdb/include/sdb.hpp b/npc/utils/sdb/include/sdb.hpp
index 54ec69b..f3e1ab0 100644
--- a/npc/utils/sdb/include/sdb.hpp
+++ b/npc/utils/sdb/include/sdb.hpp
@@ -5,6 +5,7 @@
 #include <console.hpp>
 #include <memory>
 #include <stdexcept>
+#include <string>
 #include <trm_interface.hpp>
 #include <types.h>
 
@@ -13,7 +14,12 @@ using ret = cr::Console::ReturnCode;
 
 namespace SDB {
 
-enum SDBStatus { SDB_SUCCESS, SDB_WRONG_ARGUMENT, SDB_DIFFTEST_FAILED };
+enum SDBStatus {
+  SDB_SUCCESS,
+  SDB_EBREAK = 2,
+  SDB_WRONG_ARGUMENT,
+  SDB_DIFFTEST_FAILED
+};
 
 class SDBHandlers;
 
@@ -36,10 +42,11 @@ private:
   int cmd_step(const std::vector<std::string> &input);
   int cmd_info_registers(const std::vector<std::string> &input);
   int cmd_print(const std::vector<std::string> &input);
+  int exec_catch(uint64_t);
 
 public:
   SDBHandlers(const TrmInterface &funcs) : funcs(funcs){};
-  void registerHandlers(cr::Console *c);
+  void register_handlers(cr::Console *c);
 };
 
 class SDB {
@@ -54,24 +61,34 @@ public:
       : handlers(SDBHandlers{funcs}), funcs(funcs) {
     c = std::make_unique<CppReadline::Console>(greeting);
 
-    handlers.registerHandlers(c.get());
+    handlers.register_handlers(c.get());
   };
 
   int main_loop() {
-    int retCode;
+    int ret_code;
     funcs.init(0);
+    std::vector<std::string> step_commands{"c", "continue", "si",
+                                           "step-instruction"};
     do {
-      retCode = c->readLine();
+      ret_code = c->readLine();
       // We can also change the prompt based on last return value:
-      if (retCode == ret::Ok)
+      if (ret_code == SDB_SUCCESS || ret_code == SDB_EBREAK)
         c->setGreeting("\033[1;34m(npc)\033[0m ");
       else
         c->setGreeting("\033[1;31m(npc)\033[0m ");
 
-      if (retCode == SDB_WRONG_ARGUMENT) {
-        std::cout << "Wrong argument give to command\n";
+      switch (ret_code) {
+      case SDB_EBREAK: {
+        std::cout << "\033[1;31m=== ebreak ===\033[0m" << std::endl;
+        c->removeCommands(step_commands);
+        break;
       }
-    } while (retCode != ret::Quit);
+      case SDB_WRONG_ARGUMENT: {
+        std::cout << "Wrong argument(s) is given to command handler\n";
+        break;
+      }
+      }
+    } while (ret_code != ret::Quit);
     return 0;
   }
 };
diff --git a/npc/utils/sdb/sdb.cpp b/npc/utils/sdb/sdb.cpp
index 61c8853..d38ea02 100644
--- a/npc/utils/sdb/sdb.cpp
+++ b/npc/utils/sdb/sdb.cpp
@@ -20,11 +20,28 @@ std::ostream &operator<<(std::ostream &os, const TrmInterface &d) {
 
 namespace SDB {
 
+int SDBHandlers::exec_catch(uint64_t n) {
+  try {
+    this->funcs.exec(n);
+  } catch (TrmRuntimeException &e) {
+    switch (e.error_code()) {
+    case TrmRuntimeException::EBREAK:
+      return SDB_EBREAK;
+    case TrmRuntimeException::DIFFTEST_FAILED:
+      std::cout << "Difftest Failed" << std::endl << funcs << std::endl;
+      return SDB_DIFFTEST_FAILED;
+    default:
+      std::cerr << "Unknown error code" << std::endl;
+      exit(1);
+    }
+  }
+  return SDB_SUCCESS;
+}
+
 int SDBHandlers::cmd_continue(const cr::Console::Arguments &input) {
   if (input.size() > 1)
     return SDB_WRONG_ARGUMENT;
-  this->funcs.exec(-1);
-  return SDB_SUCCESS;
+  return exec_catch(-1);
 }
 
 int SDBHandlers::cmd_step(const std::vector<std::string> &input) {
@@ -32,14 +49,8 @@ int SDBHandlers::cmd_step(const std::vector<std::string> &input) {
     return SDB_WRONG_ARGUMENT;
   }
   uint64_t step_count = input.size() == 2 ? std::stoull(input[1]) : 1;
-  try {
-    this->funcs.exec(step_count);
-  } catch (std::runtime_error) {
-    std::cout << "Difftest Failed" << std::endl << funcs << std::endl;
-    return SDB_DIFFTEST_FAILED;
-  }
+  return exec_catch(step_count);
   // std::cout << funcs << std::endl;
-  return SDB_SUCCESS;
 }
 
 int SDBHandlers::cmd_info_registers(const std::vector<std::string> &input) {
@@ -72,7 +83,7 @@ int SDBHandlers::cmd_print(const std::vector<std::string> &input) {
   return SDB_SUCCESS;
 }
 
-void SDBHandlers::registerHandlers(cr::Console *c) {
+void SDBHandlers::register_handlers(cr::Console *c) {
   for (auto &h : this->all_handlers) {
     for (auto &name : h.names) {
       std::function<int(std::vector<std::string>)> f{
@@ -81,4 +92,5 @@ void SDBHandlers::registerHandlers(cr::Console *c) {
     }
   }
 }
+
 } // namespace SDB