diff --git a/src/runtime/c/teyjus/simulator/builtins/builtins.h b/src/runtime/c/teyjus/simulator/builtins/builtins.h
new file mode 100644
index 000000000..bac897678
--- /dev/null
+++ b/src/runtime/c/teyjus/simulator/builtins/builtins.h
@@ -0,0 +1,132 @@
+//////////////////////////////////////////////////////////////////////////////
+//Copyright 2008
+//  Andrew Gacek, Steven Holte, Gopalan Nadathur, Xiaochu Qi, Zach Snow
+//////////////////////////////////////////////////////////////////////////////
+// This file is part of Teyjus.                                             //
+//                                                                          //
+// Teyjus is free software: you can redistribute it and/or modify           //
+// it under the terms of the GNU General Public License as published by     //
+// the Free Software Foundation, either version 3 of the License, or        //
+// (at your option) any later version.                                      //
+//                                                                          //
+// Teyjus is distributed in the hope that it will be useful,                //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of           //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            //
+// GNU General Public License for more details.                             //
+//                                                                          //
+// You should have received a copy of the GNU General Public License        //
+// along with Teyjus.  If not, see <http://www.gnu.org/licenses/>.          //
+//////////////////////////////////////////////////////////////////////////////
+
+/*****************************************************************************/
+/*                                                                           */
+/* File builtins.h. This files defines the indexes of the builtin table, and */
+/* provides signature for the function indexing into the builtin table and   */
+/* invokes the appropriate function.                                         */
+/*****************************************************************************/ 
+
+#ifndef BUILTINS_H
+#define BUILTINS_H
+
+#include "../../system/error.h"
+
+/***********************************************************************/
+/*             Builtin Dispatch Table Index                            */
+/***********************************************************************/
+typedef enum
+{
+    BI_SOLVE          = 0,
+    BI_EVAL           = 1,
+    BI_NOT            = 2,
+    BI_UNIFY          = 3,
+    // comparison operations
+    BI_INT_LT         = 4, 
+    BI_INT_GT         = 5,
+    BI_INT_LE         = 6,
+    BI_INT_GE         = 7,
+    BI_FLOAT_LT       = 8,
+    BI_FLOAT_GT       = 9, 
+    BI_FLOAT_LE       = 10,
+    BI_FLOAT_GE       = 11,
+    BI_STR_LT         = 12,
+    BI_STR_GT         = 13,
+    BI_STR_LE         = 14,
+    BI_STR_GE         = 15,
+    //IO
+    BI_IO_OPEN_IN     = 16,
+    BI_IO_OPEN_OUT    = 17,
+    BI_IO_OPEN_APP    = 18,
+    BI_IO_CLOSE_IN    = 19,
+    BI_IO_CLOSE_OUT   = 20,
+    BI_IO_OPEN_STR    = 21,
+    BI_IO_INPUT       = 22,
+    BI_IO_OUTPUT      = 23,
+    BI_IO_INPUT_LINE  = 24,
+    BI_IO_LOOKAHEAD   = 25,
+    BI_IO_EOF         = 26,
+    BI_IO_FLUSH       = 27,
+    BI_IO_PRINT       = 28,
+    BI_IO_READ        = 29,
+    BI_IO_PRINTTERM   = 30,
+    BI_IO_TERM_TO_STR = 31,
+    BI_IO_STR_TO_TERM = 32,
+    BI_IO_READTERM    = 33,
+    BI_IO_GETENV      = 34,
+    BI_IO_OPEN_SOCKET = 35,
+    BI_UNIX_TIME      = 36,
+    BI_SYSTEM         = 37
+} BI_BuiltinTabIndex;
+
+/*****************************************************************************/
+/* Dispatching function for the builtin table                                */
+/*****************************************************************************/ 
+void BI_dispatch(int number);
+
+/* builtin index "register"*/
+extern BI_BuiltinTabIndex BI_number;
+
+/***************************######********************************************
+ *                          ERROR INFORMATION
+ *********************************######**************************************/
+
+#define BI_NUM_ERROR_MESSAGES 28
+enum
+{
+   BI_ERROR = BI_FIRST_ERR_INDEX,
+   BI_ERROR_TERM,
+   BI_ERROR_NOT_IMPLEMENTED,
+   BI_ERROR_FVAR_CAP,
+   BI_ERROR_TYFVAR_CAP,
+   BI_ERROR_DIV_BY_ZERO,
+   BI_ERROR_NEG_SQRT,
+   BI_ERROR_NEG_LOG,
+   BI_ERROR_CONST_IND,
+   BI_ERROR_FLEX_HEAD,		/* takes term */
+   BI_ERROR_ILLEGAL_ARG,	/* takes term */
+   BI_ERROR_EVAL_TYPE,
+   BI_ERROR_ILLEGAL_STREAM,
+   BI_ERROR_FLEX_GOAL,
+   BI_ERROR_NON_VAR_TERM,	/* takes term */
+   BI_ERROR_INDEX_OUT_OF_BOUNDS,
+   BI_ERROR_NEGATIVE_VALUE,
+   BI_ERROR_UNBOUND_VARIABLE,	/* takes string indicating desired arg. */
+   BI_ERROR_NON_STREAM_TERM,	/* takes term */
+   BI_ERROR_STREAM_ALREADY_CLOSED,
+   BI_ERROR_CANNOT_OPEN_STREAM,	/* takes filename */
+   BI_ERROR_STREAM,		/* takes term (stream) */
+   BI_ERROR_READING_STREAM,	/* takes term (stream) */
+   BI_ERROR_WRITING_STREAM,	/* takes term (stream) */
+   BI_ERROR_FLUSHING_STREAM,	/* takes term (stream) */
+   BI_ERROR_OPENING_STRING,	/* takes string */
+   BI_ERROR_INTEGER_EXPECTED,	/* takes term */
+   BI_ERROR_SUBSTRING
+};
+
+
+
+/***************************######********************************************
+ *                            Initialization
+ *********************************######**************************************/
+void BI_init();
+
+#endif //BUILTINS_H