diff --git a/PExpr.h b/PExpr.h
index 2a2217d59..a9387ca17 100644
--- a/PExpr.h
+++ b/PExpr.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: PExpr.h,v 1.74 2005/11/27 17:01:56 steve Exp $"
+#ident "$Id: PExpr.h,v 1.75 2005/12/07 04:04:23 steve Exp $"
 #endif
 
 # include  <string>
@@ -122,6 +122,7 @@ class PEConcat : public PExpr {
       PEConcat(const svector<PExpr*>&p, PExpr*r =0);
       ~PEConcat();
 
+      virtual verinum* eval_const(const Design*des, NetScope*sc) const;
       virtual void dump(ostream&) const;
 
       virtual NetNet* elaborate_lnet(Design*des, NetScope*scope,
@@ -545,6 +546,9 @@ class PECallFunction : public PExpr {
 
 /*
  * $Log: PExpr.h,v $
+ * Revision 1.75  2005/12/07 04:04:23  steve
+ *  Allow constant concat expressions.
+ *
  * Revision 1.74  2005/11/27 17:01:56  steve
  *  Fix for stubborn compiler.
  *
diff --git a/eval.cc b/eval.cc
index 902aa6e98..202aec1de 100644
--- a/eval.cc
+++ b/eval.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: eval.cc,v 1.38 2005/11/27 17:01:57 steve Exp $"
+#ident "$Id: eval.cc,v 1.39 2005/12/07 04:04:23 steve Exp $"
 #endif
 
 # include "config.h"
@@ -143,6 +143,22 @@ verinum* PEBinary::eval_const(const Design*des, NetScope*scope) const
       delete r;
       return res;
 }
+verinum* PEConcat::eval_const(const Design*des, NetScope*scope) const
+{
+      verinum*accum = parms_[0]->eval_const(des, scope);
+      if (accum == 0)
+	    return 0;
+
+      for (unsigned idx = 1 ;  idx < parms_.count() ;  idx += 1) {
+	    verinum*tmp = parms_[idx]->eval_const(des, scope);
+	    assert(tmp);
+
+	    *accum = concat(*accum, *tmp);
+	    delete tmp;
+      }
+
+      return accum;
+}
 
 
 /*
@@ -247,6 +263,9 @@ verinum* PEUnary::eval_const(const Design*des, NetScope*scope) const
 
 /*
  * $Log: eval.cc,v $
+ * Revision 1.39  2005/12/07 04:04:23  steve
+ *  Allow constant concat expressions.
+ *
  * Revision 1.38  2005/11/27 17:01:57  steve
  *  Fix for stubborn compiler.
  *
diff --git a/verinum.cc b/verinum.cc
index 04cb4c775..5d554b110 100644
--- a/verinum.cc
+++ b/verinum.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: verinum.cc,v 1.43 2004/05/18 18:43:15 steve Exp $"
+#ident "$Id: verinum.cc,v 1.44 2005/12/07 04:04:24 steve Exp $"
 #endif
 
 # include "config.h"
@@ -902,6 +902,24 @@ verinum operator % (const verinum&left, const verinum&right)
       return result;
 }
 
+verinum concat(const verinum&left, const verinum&right)
+{
+      if (left.is_string() && right.is_string()) {
+	    std::string tmp = left.as_string() + right.as_string();
+	    verinum res (tmp);
+	    return res;
+      }
+
+      verinum res (verinum::V0, left.len() + right.len());
+      for (unsigned idx = 0 ;  idx < right.len() ;  idx += 1)
+	    res.set(idx, right.get(idx));
+
+      for (unsigned idx = 0 ;  idx < left.len() ;  idx += 1)
+	    res.set(idx+right.len(), left.get(idx));
+
+      return res;
+}
+
 verinum::V operator | (verinum::V l, verinum::V r)
 {
       if (l == verinum::V1)
@@ -942,6 +960,9 @@ verinum::V operator ^ (verinum::V l, verinum::V r)
 
 /*
  * $Log: verinum.cc,v $
+ * Revision 1.44  2005/12/07 04:04:24  steve
+ *  Allow constant concat expressions.
+ *
  * Revision 1.43  2004/05/18 18:43:15  steve
  *  Handle null string as a single nul character.
  *
diff --git a/verinum.h b/verinum.h
index 5bc8a29b7..40e84424e 100644
--- a/verinum.h
+++ b/verinum.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: verinum.h,v 1.27 2005/06/14 19:13:43 steve Exp $"
+#ident "$Id: verinum.h,v 1.28 2005/12/07 04:04:24 steve Exp $"
 #endif
 
 # include  <string>
@@ -144,11 +144,16 @@ extern verinum operator % (const verinum&left, const verinum&right);
 extern verinum operator<< (const verinum&left, unsigned shift);
 extern verinum operator>> (const verinum&left, unsigned shift);
 
+extern verinum concat(const verinum&left, const verinum&right);
+
 /* Bitwise not returns the ones complement. */
 extern verinum v_not(const verinum&left);
 
 /*
  * $Log: verinum.h,v $
+ * Revision 1.28  2005/12/07 04:04:24  steve
+ *  Allow constant concat expressions.
+ *
  * Revision 1.27  2005/06/14 19:13:43  steve
  *  gcc3/4 compile errors.
  *