diff --git a/vpi/sdf_parse.y b/vpi/sdf_parse.y
index 69d57300d..f4859add1 100644
--- a/vpi/sdf_parse.y
+++ b/vpi/sdf_parse.y
@@ -1,7 +1,7 @@
 
 %{
 /*
- * Copyright (c) 1998-2007 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 1998-2009 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
@@ -38,6 +38,7 @@ char sdf_use_hchar = '.';
       double real_val;
       char*  string_val;
 
+      struct sdf_delay_s delay;
       struct port_with_edge_s port_with_edge;
       struct sdf_delval_list_s delval_list;
 };
@@ -58,8 +59,8 @@ char sdf_use_hchar = '.';
 %type <string_val> hierarchical_identifier
 %type <string_val> port port_instance
 
-%type <real_val> rvalue rtriple signed_real_number
-%type <real_val> delval
+%type <real_val> rtriple signed_real_number
+%type <delay> delval rvalue
 
 %type <int_val> edge_identifier
 %type <port_with_edge> port_edge port_spec
@@ -315,6 +316,7 @@ delval_list
 	$$.count = $1.count;
 	for (idx = 0 ; idx < $$.count ; idx += 1)
 	      $$.val[idx] = $1.val[idx];
+// Is this correct?
 	if ($$.count < 12) {
 	      $$.val[$$.count] = $2;
 	      $$.count += 1;
@@ -343,9 +345,14 @@ delval
 
 rvalue
   : '(' signed_real_number ')'
-      { $$ = $2; }
+      { $$.defined = 1;
+        $$.value = $2; }
   | '(' rtriple ')'
-      { $$ = $2; }
+      { $$.defined = 1;
+        $$.value = $2; }
+  | '(' ')'
+      { $$.defined = 0;
+        $$.value = 0.0; }
   ;
 
 hierarchical_identifier
diff --git a/vpi/sdf_priv.h b/vpi/sdf_priv.h
index a71d76958..e336c9360 100644
--- a/vpi/sdf_priv.h
+++ b/vpi/sdf_priv.h
@@ -1,7 +1,7 @@
 #ifndef _sdf_priv_h
 #define _sdf_priv_h
 /*
- * Copyright (c) 2007 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2007-2009 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
@@ -36,9 +36,14 @@ extern int sdf_flag_inform;
  * it is parsed.
  */
 
+struct sdf_delay_s {
+      int defined;
+      double value;
+};
+
 struct sdf_delval_list_s {
       int count;
-      double val[12];
+      struct sdf_delay_s val[12];
 };
 
 extern void sdf_select_instance(const char*celltype, const char*inst);
diff --git a/vpi/sys_sdf.c b/vpi/sys_sdf.c
index fe2210e28..e89e4943c 100644
--- a/vpi/sys_sdf.c
+++ b/vpi/sys_sdf.c
@@ -139,33 +139,22 @@ static const char*edge_str(int vpi_edge)
 void sdf_iopath_delays(int vpi_edge, const char*src, const char*dst,
 		       const struct sdf_delval_list_s*delval_list)
 {
-      s_vpi_delay delays;
+      vpiHandle iter, path;
+      int match_count = 0;
+
       if (sdf_cur_cell == 0)
 	    return;
 
-      vpiHandle iter = vpi_iterate(vpiModPath, sdf_cur_cell);
-
-      struct t_vpi_time delay_vals[12];
-      int idx;
-      for (idx = 0 ; idx < delval_list->count ; idx += 1) {
-	    delay_vals[idx].type = vpiScaledRealTime;
-	    delay_vals[idx].real = delval_list->val[idx];
-      }
-
-      delays.da = delay_vals;
-      delays.no_of_delays = delval_list->count;
-      delays.time_type = vpiScaledRealTime;
-      delays.mtm_flag = 0;
-      delays.append_flag = 0;
-      delays.plusere_flag = 0;
-
+      iter = vpi_iterate(vpiModPath, sdf_cur_cell);
 
 	/* Search for the modpath that matches the IOPATH by looking
 	   for the modpath that uses the same ports as the ports that
 	   the parser has found. */
-      vpiHandle path;
-      int match_count = 0;
       if (iter) while ( (path = vpi_scan(iter)) ) {
+	    s_vpi_delay delays;
+	    struct t_vpi_time delay_vals[12];
+	    int idx;
+
 	    vpiHandle path_t_in = vpi_handle(vpiModPathIn,path);
 	    vpiHandle path_t_out = vpi_handle(vpiModPathOut,path);
 
@@ -192,6 +181,22 @@ void sdf_iopath_delays(int vpi_edge, const char*src, const char*dst,
 		  continue;
 
 	      /* Ah, this must be a match! */
+	    delays.da = delay_vals;
+	    delays.no_of_delays = delval_list->count;
+	    delays.time_type = vpiScaledRealTime;
+	    delays.mtm_flag = 0;
+	    delays.append_flag = 0;
+	    delays.plusere_flag = 0;
+	    vpi_get_delays(path, &delays);
+
+	    for (idx = 0 ; idx < delval_list->count ; idx += 1) {
+		  delay_vals[idx].type = vpiScaledRealTime;
+		  if (delval_list->val[idx].defined) {
+			delay_vals[idx].real = delval_list->val[idx].value;
+		  }
+ 
+	    }
+
 	    vpi_put_delays(path, &delays);
 	    match_count += 1;
       }
diff --git a/vvp/delay.cc b/vvp/delay.cc
index 31b30367a..ab250c03d 100644
--- a/vvp/delay.cc
+++ b/vvp/delay.cc
@@ -768,23 +768,27 @@ static void modpath_src_get_delays ( vpiHandle ref, p_vpi_delay delays )
       fun->get_delay12(tmp);
 
       switch (delays->no_of_delays) {
+	  case 1:
+	  case 2:
+	  case 3:
+	  case 6:
 	  case 12:
-	    if (delays->time_type == vpiSimTime) {
-		  for (idx = 0; idx < 12; idx += 1) {
-			vpip_time_to_timestruct(delays->da+idx, tmp[idx]);
-		  }
-	    } else {
-		  /* int units = src->dest->scope->time_units; */
-		  for (idx = 0; idx < 12; idx += 1) {
-			delays->da[idx].real = vpip_time_to_scaled_real(tmp[idx], src->dest->scope);
-		  }
-	    }
 	    break;
 
 	  default:
 	    assert(0);
 	    break;
       }
+
+      if (delays->time_type == vpiSimTime) {
+	    for (idx = 0; idx < delays->no_of_delays; idx += 1) {
+		  vpip_time_to_timestruct(delays->da+idx, tmp[idx]);
+	    }
+      } else {
+	    for (idx = 0; idx < delays->no_of_delays; idx += 1) {
+		  delays->da[idx].real = vpip_time_to_scaled_real(tmp[idx], src->dest->scope);
+	    }
+      }
 }
 
 static int pathterm_get(int code, vpiHandle ref)