diff --git a/elab_sig.cc b/elab_sig.cc
index 789748e3d..4b7e10e53 100644
--- a/elab_sig.cc
+++ b/elab_sig.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: elab_sig.cc,v 1.7 2000/12/11 00:31:43 steve Exp $"
+#ident "$Id: elab_sig.cc,v 1.8 2001/01/04 04:47:51 steve Exp $"
 #endif
 
 # include  "Module.h"
@@ -325,8 +325,17 @@ void PWire::elaborate_sig(Design*des, NetScope*scope) const
 	      // If the register has indices, then this is a
 	      // memory. Create the memory object.
 	    verinum*lval = lidx_->eval_const(des, path);
-	    assert(lval);
 	    verinum*rval = ridx_->eval_const(des, path);
+
+	    if ((lval == 0) || (rval == 0)) {
+		  cerr << get_line() << ": internal error: There is "
+		       << "a problem evaluating indices for ``"
+		       << basename << "''." << endl;
+		  des->errors += 1;
+		  return;
+	    }
+
+	    assert(lval);
 	    assert(rval);
 
 	    long lnum = lval->as_long();
@@ -348,6 +357,9 @@ void PWire::elaborate_sig(Design*des, NetScope*scope) const
 
 /*
  * $Log: elab_sig.cc,v $
+ * Revision 1.8  2001/01/04 04:47:51  steve
+ *  Add support for << is signal indices.
+ *
  * Revision 1.7  2000/12/11 00:31:43  steve
  *  Add support for signed reg variables,
  *  simulate in t-vvm signed comparisons.
diff --git a/eval.cc b/eval.cc
index 70cb4a1ae..0c4384af6 100644
--- a/eval.cc
+++ b/eval.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: eval.cc,v 1.16 2000/12/10 22:01:36 steve Exp $"
+#ident "$Id: eval.cc,v 1.17 2001/01/04 04:47:51 steve Exp $"
 #endif
 
 # include  "PExpr.h"
@@ -81,12 +81,26 @@ verinum* PEBinary::eval_const(const Design*des, const string&path) const
 		res = new verinum(lv % rv, l->len());
 		break;
 	  }
+	  case 'l': {
+		assert(r->is_defined());
+		unsigned long rv = r->as_ulong();
+		res = new verinum(verinum::V0, l->len());
+		if (rv < res->len()) {
+		      unsigned cnt = res->len() - rv;
+		      for (unsigned idx = 0 ;  idx < cnt ;  idx += 1)
+			    res->set(idx+rv, l->get(idx));
+		}
+		break;
+	  }
+
 	  default:
 	    delete l;
 	    delete r;
 	    return 0;
       }
 
+      delete l;
+      delete r;
       return res;
 }
 
@@ -169,6 +183,9 @@ verinum* PEUnary::eval_const(const Design*des, const string&path) const
 
 /*
  * $Log: eval.cc,v $
+ * Revision 1.17  2001/01/04 04:47:51  steve
+ *  Add support for << is signal indices.
+ *
  * Revision 1.16  2000/12/10 22:01:36  steve
  *  Support decimal constants in behavioral delays.
  *