diff --git a/vpi_user.h b/vpi_user.h
index e29184223..3645309fb 100644
--- a/vpi_user.h
+++ b/vpi_user.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vpi_user.h,v 1.15 2002/08/12 01:35:01 steve Exp $"
+#ident "$Id: vpi_user.h,v 1.16 2003/01/09 04:10:17 steve Exp $"
 #endif
 
 
@@ -323,6 +323,13 @@ extern vpiHandle vpi_put_value(vpiHandle obj, p_vpi_value value,
 extern int vpi_free_object(vpiHandle ref);
 extern int vpi_get_vlog_info(p_vpi_vlog_info vlog_info_p);
 
+/*
+ * These functions support attaching user data to an instance of a
+ * system task or function. These functions only apply to
+ * vpiSysTaskCall or vpiSysFuncCall handles.
+ */
+extern int  vpi_put_userdata(vpiHandle obj, void*data);
+extern void*vpi_get_userdata(vpiHandle obj);
 
 /*
  * Support for handling errors.
@@ -359,6 +366,9 @@ EXTERN_C_END
 
 /*
  * $Log: vpi_user.h,v $
+ * Revision 1.16  2003/01/09 04:10:17  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.15  2002/08/12 01:35:01  steve
  *  conditional ident string using autoconfig.
  *
diff --git a/vpithunk.c b/vpithunk.c
index a3b0623d3..9e7eeeb2e 100644
--- a/vpithunk.c
+++ b/vpithunk.c
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vpithunk.c,v 1.7 2002/12/11 23:55:22 steve Exp $"
+#ident "$Id: vpithunk.c,v 1.8 2003/01/09 04:10:17 steve Exp $"
 #endif
 
 #include <stdio.h>
@@ -235,8 +235,21 @@ extern int vpi_chk_error(p_vpi_error_info info)
   VPIT_CALL(vpi_chk_error, 0, (info));
 }
 
+extern void* vpi_get_userdata(vpiHandle obj)
+{
+      VPIT_CALL(vpi_get_userdata, 0, (obj));
+}
+
+extern int vpi_put_userdata(vpiHandle obj, void*data)
+{
+      VPIT_CALL(vpi_put_userdata, 0, (obj, data));
+}
+
 /*
  * $Log: vpithunk.c,v $
+ * Revision 1.8  2003/01/09 04:10:17  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.7  2002/12/11 23:55:22  steve
  *  Add vpi_handle_by_name to the VPI interface,
  *  and bump the vpithunk magic number.
diff --git a/vpithunk.h b/vpithunk.h
index 7e2aa09d4..bcb17fa0c 100644
--- a/vpithunk.h
+++ b/vpithunk.h
@@ -2,7 +2,7 @@
 #define _VPI_THUNK_H_ 1
 
 /*
- * Copyright (c) 2001-2002 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001-2003 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -20,7 +20,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vpithunk.h,v 1.5 2002/12/11 23:55:22 steve Exp $"
+#ident "$Id: vpithunk.h,v 1.6 2003/01/09 04:10:17 steve Exp $"
 #endif
 
 /* These functions are actually defined in lieu of the vpi functions
@@ -70,6 +70,15 @@ typedef struct {
   int (*vpi_get_vlog_info)(p_vpi_vlog_info vlog_info_p);
   int (*vpi_chk_error)(p_vpi_error_info info);
   vpiHandle (*vpi_handle_by_name)(char *name, vpiHandle scope);
+
+  int   (*vpi_put_userdata)(vpiHandle obj, void*data);
+  void* (*vpi_get_userdata)(vpiHandle obj);
+
+      void*pad3;
+      void*pad2;
+      void*pad1;
+      void*pad0;
+
 } vpi_thunk, *p_vpi_thunk;
 
 DLLEXPORT int vpi_register_sim(p_vpi_thunk tp);
@@ -78,6 +87,9 @@ DLLEXPORT int vpi_register_sim(p_vpi_thunk tp);
 
 /*
  * $Log: vpithunk.h,v $
+ * Revision 1.6  2003/01/09 04:10:17  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.5  2002/12/11 23:55:22  steve
  *  Add vpi_handle_by_name to the VPI interface,
  *  and bump the vpithunk magic number.
diff --git a/vvp/vpi_priv.h b/vvp/vpi_priv.h
index d06b1acfc..05c9d2144 100644
--- a/vvp/vpi_priv.h
+++ b/vvp/vpi_priv.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vpi_priv.h,v 1.41 2002/12/21 00:55:58 steve Exp $"
+#ident "$Id: vpi_priv.h,v 1.42 2003/01/09 04:09:44 steve Exp $"
 #endif
 
 # include  "vpi_user.h"
@@ -240,7 +240,8 @@ struct __vpiSysTaskCall {
       struct __vpiUserSystf*defn;
       unsigned nargs;
       vpiHandle*args;
-
+	/* Support for vpi_get_userdata. */
+      void*userdata;
 	/* These represent where in the vthread to put the return value. */
       unsigned short vbit, vwid;
 };
@@ -384,6 +385,9 @@ extern char *need_result_buf(unsigned cnt, vpi_rbuf_t type);
 
 /*
  * $Log: vpi_priv.h,v $
+ * Revision 1.42  2003/01/09 04:09:44  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.41  2002/12/21 00:55:58  steve
  *  The $time system task returns the integer time
  *  scaled to the local units. Change the internal
diff --git a/vvp/vpi_tasks.cc b/vvp/vpi_tasks.cc
index f88652bec..987dcbe33 100644
--- a/vvp/vpi_tasks.cc
+++ b/vvp/vpi_tasks.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vpi_tasks.cc,v 1.17 2002/12/21 00:55:58 steve Exp $"
+#ident "$Id: vpi_tasks.cc,v 1.18 2003/01/09 04:09:44 steve Exp $"
 #endif
 
 /*
@@ -276,6 +276,7 @@ vpiHandle vpip_build_vpi_call(const char*name, unsigned vbit, unsigned vwid,
       obj->args  = argv;
       obj->vbit  = vbit;
       obj->vwid  = vwid;
+      obj->userdata = 0;
 
 	/* If there is a compiletf function, call it here. */
       if (obj->defn->info.compiletf) {
@@ -342,8 +343,31 @@ void vpi_register_systf(const struct t_vpi_systf_data*ss)
       cur->info.tfname = strdup(ss->tfname);
 }
 
+int vpi_put_userdata(vpiHandle ref, void*data)
+{
+      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;
+      assert((ref->vpi_type->type_code == vpiSysTaskCall)
+	     || (ref->vpi_type->type_code == vpiSysFuncCall));
+
+      rfp->userdata = data;
+      return 0;
+}
+
+void* vpi_get_userdata(vpiHandle ref)
+{
+      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;
+      assert((ref->vpi_type->type_code == vpiSysTaskCall)
+	     || (ref->vpi_type->type_code == vpiSysFuncCall));
+
+      return rfp->userdata;
+}
+
+
 /*
  * $Log: vpi_tasks.cc,v $
+ * Revision 1.18  2003/01/09 04:09:44  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.17  2002/12/21 00:55:58  steve
  *  The $time system task returns the integer time
  *  scaled to the local units. Change the internal
diff --git a/vvp/vvp_vpi.cc b/vvp/vvp_vpi.cc
index ad5f9d632..991688551 100644
--- a/vvp/vvp_vpi.cc
+++ b/vvp/vvp_vpi.cc
@@ -1,5 +1,5 @@
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vvp_vpi.cc,v 1.6 2002/12/11 23:55:22 steve Exp $"
+#ident "$Id: vvp_vpi.cc,v 1.7 2003/01/09 04:09:44 steve Exp $"
 #endif
 
 #include <stdarg.h>
@@ -36,10 +36,15 @@ void vvp_vpi_init()
   vvpt.vpi_free_object= vpi_free_object;
   vvpt.vpi_get_vlog_info = vpi_get_vlog_info;
   vvpt.vpi_chk_error = vpi_chk_error;
+  vvpt.vpi_get_userdata = vpi_get_userdata;
+  vvpt.vpi_put_userdata = vpi_put_userdata;
 }
 
 /*
  * $Log: vvp_vpi.cc,v $
+ * Revision 1.7  2003/01/09 04:09:44  steve
+ *  Add vpi_put_userdata
+ *
  * Revision 1.6  2002/12/11 23:55:22  steve
  *  Add vpi_handle_by_name to the VPI interface,
  *  and bump the vpithunk magic number.