diff --git a/openfpga/src/base/openfpga_bitstream_command.cpp b/openfpga/src/base/openfpga_bitstream_command.cpp
new file mode 100644
index 000000000..827dd1eca
--- /dev/null
+++ b/openfpga/src/base/openfpga_bitstream_command.cpp
@@ -0,0 +1,38 @@
+/********************************************************************
+ * Add commands to the OpenFPGA shell interface, 
+ * in purpose of generate Verilog netlists modeling the full FPGA fabric
+ * This is one of the core engine of openfpga, including:
+ * - repack : create physical pbs and redo packing 
+ *******************************************************************/
+#include "openfpga_repack.h"
+#include "openfpga_bitstream_command.h"
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+void add_openfpga_bitstream_commands(openfpga::Shell<OpenfpgaContext>& shell) {
+  /* Get the unique id of 'build_fabric' command which is to be used in creating the dependency graph */
+  const ShellCommandId& shell_cmd_build_fabric_id = shell.command(std::string("build_fabric"));
+
+  /* Add a new class of commands */
+  ShellCommandClassId openfpga_bitstream_cmd_class = shell.add_command_class("FPGA-Bitstream");
+
+  /******************************** 
+   * Command 'repack' 
+   */
+  Command shell_cmd_repack("repack");
+  /* Add an option '--verbose' */
+  shell_cmd_repack.add_option("verbose", false, "Enable verbose output");
+  
+  /* Add command 'repack' to the Shell */
+  ShellCommandId shell_cmd_repack_id = shell.add_command(shell_cmd_repack, "Pack physical programmable logic blocks");
+  shell.set_command_class(shell_cmd_repack_id, openfpga_bitstream_cmd_class);
+  shell.set_command_execute_function(shell_cmd_repack_id, repack);
+
+  /* The 'repack' command should NOT be executed before 'build_fabric' */
+  std::vector<ShellCommandId> cmd_dependency_repack;
+  cmd_dependency_repack.push_back(shell_cmd_build_fabric_id);
+  shell.set_command_dependency(shell_cmd_repack_id, cmd_dependency_repack);
+} 
+
+} /* end namespace openfpga */
diff --git a/openfpga/src/base/openfpga_bitstream_command.h b/openfpga/src/base/openfpga_bitstream_command.h
new file mode 100644
index 000000000..d58555dd8
--- /dev/null
+++ b/openfpga/src/base/openfpga_bitstream_command.h
@@ -0,0 +1,21 @@
+#ifndef OPENFPGA_BITSTREAM_COMMAND_H
+#define OPENFPGA_BITSTREAM_COMMAND_H
+
+/********************************************************************
+ * Include header files that are required by function declaration
+ *******************************************************************/
+#include "shell.h"
+#include "openfpga_context.h"
+
+/********************************************************************
+ * Function declaration
+ *******************************************************************/
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+void add_openfpga_bitstream_commands(openfpga::Shell<OpenfpgaContext>& shell); 
+
+} /* end namespace openfpga */
+
+#endif
diff --git a/openfpga/src/base/openfpga_repack.cpp b/openfpga/src/base/openfpga_repack.cpp
new file mode 100644
index 000000000..f605233da
--- /dev/null
+++ b/openfpga/src/base/openfpga_repack.cpp
@@ -0,0 +1,33 @@
+/********************************************************************
+ * This file includes functions to compress the hierachy of routing architecture
+ *******************************************************************/
+/* Headers from vtrutil library */
+#include "vtr_time.h"
+#include "vtr_log.h"
+
+#include "verilog_api.h"
+#include "repack.h"
+#include "openfpga_repack.h"
+
+/* Include global variables of VPR */
+#include "globals.h"
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+/********************************************************************
+ * A wrapper function to call the fabric_verilog function of FPGA-Verilog 
+ *******************************************************************/
+void repack(OpenfpgaContext& openfpga_ctx,
+            const Command& cmd, const CommandContext& cmd_context) {
+
+  CommandOptionId opt_verbose = cmd.option("verbose");
+
+  pack_physical_pbs(g_vpr_ctx.device(),
+                    openfpga_ctx.mutable_vpr_device_annotation(),
+                    openfpga_ctx.mutable_vpr_clustering_annotation(),
+                    openfpga_ctx.vpr_routing_annotation(),
+                    cmd_context.option_enable(cmd, opt_verbose));
+} 
+
+} /* end namespace openfpga */
diff --git a/openfpga/src/base/openfpga_repack.h b/openfpga/src/base/openfpga_repack.h
new file mode 100644
index 000000000..0fce62f78
--- /dev/null
+++ b/openfpga/src/base/openfpga_repack.h
@@ -0,0 +1,23 @@
+#ifndef OPENFPGA_REPACK_H
+#define OPENFPGA_REPACK_H
+
+/********************************************************************
+ * Include header files that are required by function declaration
+ *******************************************************************/
+#include "command.h"
+#include "command_context.h"
+#include "openfpga_context.h"
+
+/********************************************************************
+ * Function declaration
+ *******************************************************************/
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+void repack(OpenfpgaContext& openfpga_ctx,
+            const Command& cmd, const CommandContext& cmd_context); 
+
+} /* end namespace openfpga */
+
+#endif
diff --git a/openfpga/src/main.cpp b/openfpga/src/main.cpp
index 792223e3c..c018db4bf 100644
--- a/openfpga/src/main.cpp
+++ b/openfpga/src/main.cpp
@@ -13,6 +13,7 @@
 #include "vpr_command.h"
 #include "openfpga_setup_command.h"
 #include "openfpga_verilog_command.h"
+#include "openfpga_bitstream_command.h"
 #include "basic_command.h"
 
 #include "openfpga_title.h"
@@ -56,6 +57,9 @@ int main(int argc, char** argv) {
   /* Add openfpga verilog commands */
   openfpga::add_openfpga_verilog_commands(shell);
 
+  /* Add openfpga bitstream commands */
+  openfpga::add_openfpga_bitstream_commands(shell);
+
   /* Add basic commands: exit, help, etc. 
    * Note:
    * This MUST be the last command group to be added! 
diff --git a/openfpga/src/repack/repack.cpp b/openfpga/src/repack/repack.cpp
new file mode 100644
index 000000000..2a7dada40
--- /dev/null
+++ b/openfpga/src/repack/repack.cpp
@@ -0,0 +1,32 @@
+/***************************************************************************************
+ * This file includes functions that are used to redo packing for physical pbs
+ ***************************************************************************************/
+
+/* Headers from vtrutil library */
+#include "vtr_log.h"
+#include "vtr_assert.h"
+#include "vtr_time.h"
+
+#include "repack.h"
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+/***************************************************************************************
+ * Top-level function to pack physical pb_graph 
+ * This function will do :
+ *  - create physical lb_rr_graph for each pb_graph considering physical modes only
+ *    the lb_rr_graph willbe added to device annotation
+ *  - annotate nets to be routed for each clustered block from operating modes of pb_graph 
+ *    to physical modes of pb_graph
+ *  - rerun the routing for each clustered block
+ *  - store the packing results to clustering annotation
+ ***************************************************************************************/
+void pack_physical_pbs(const DeviceContext& device_ctx,
+                       VprDeviceAnnotation& device_annotation,
+                       VprClusteringAnnotation& clustering_annotation,
+                       const VprRoutingAnnotation& routing_annotation,
+                       const bool& verbose) {
+}
+
+} /* end namespace openfpga */
diff --git a/openfpga/src/repack/repack.h b/openfpga/src/repack/repack.h
new file mode 100644
index 000000000..733a7d1ac
--- /dev/null
+++ b/openfpga/src/repack/repack.h
@@ -0,0 +1,27 @@
+#ifndef REPACK_H
+#define REPACK_H
+
+/********************************************************************
+ * Include header files that are required by function declaration
+ *******************************************************************/
+#include "vpr_context.h"
+#include "vpr_device_annotation.h"
+#include "vpr_clustering_annotation.h"
+#include "vpr_routing_annotation.h"
+
+/********************************************************************
+ * Function declaration
+ *******************************************************************/
+
+/* begin namespace openfpga */
+namespace openfpga {
+
+void pack_physical_pbs(const DeviceContext& device_ctx,
+                       VprDeviceAnnotation& device_annotation,
+                       VprClusteringAnnotation& clustering_annotation,
+                       const VprRoutingAnnotation& routing_annotation,
+                       const bool& verbose);
+
+} /* end namespace openfpga */
+
+#endif