diff --git a/eval_tree.cc b/eval_tree.cc
index 3619f9200..acf63de12 100644
--- a/eval_tree.cc
+++ b/eval_tree.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_tree.cc,v 1.16 2001/01/01 21:49:33 steve Exp $"
+#ident "$Id: eval_tree.cc,v 1.17 2001/01/02 03:23:40 steve Exp $"
 #endif
 
 # include  "netlist.h"
@@ -72,6 +72,72 @@ NetEConst* NetEBAdd::eval_tree()
       return new NetEConst(val);
 }
 
+NetEConst* NetEBBits::eval_tree()
+{
+      eval_sub_tree_();
+
+      NetEConst*lc = dynamic_cast<NetEConst*>(left_);
+      if (lc == 0) return 0;
+      NetEConst*rc = dynamic_cast<NetEConst*>(right_);
+      if (rc == 0) return 0;
+
+      verinum lval = lc->value();
+      verinum rval = rc->value();
+
+      unsigned lwid = lc->expr_width();
+      if (lwid == 0) lwid = lval.len();
+
+      unsigned rwid = rc->expr_width();
+      if (rwid == 0) rwid = rval.len();
+
+      unsigned wid = expr_width();
+      if (wid == 0)
+	    wid = (rwid > lwid)? rwid : lwid;
+
+      verinum res (verinum::V0, wid);
+
+      if (lwid > wid)
+	    lwid = wid;
+      if (rwid > wid)
+	    rwid = wid;
+
+      switch (op()) {
+
+	  case '|': {
+		unsigned cnt = lwid;
+		if (cnt > wid)  cnt = wid;
+		if (cnt > rwid) cnt = rwid;
+		for (unsigned idx = 0 ;  idx < cnt ;  idx += 1)
+		      res.set(idx, lval.get(idx) | rval.get(idx));
+
+		if (lwid < rwid)
+		      for (unsigned idx = lwid ;  idx < rwid ;  idx += 1)
+			    res.set(idx, lval.get(idx));
+
+		if (rwid < lwid)
+		      for (unsigned idx = rwid ;  idx < lwid ;  idx += 1)
+			    res.set(idx, rval.get(idx));
+
+		break;
+	  }
+
+	  case '&': {
+		unsigned cnt = lwid;
+		if (cnt > wid)  cnt = wid;
+		if (cnt > rwid) cnt = rwid;
+		for (unsigned idx = 0 ;  idx < cnt ;  idx += 1)
+		      res.set(idx, lval.get(idx) & rval.get(idx));
+
+		break;
+	  }
+
+	  default:
+	    return 0;
+      }
+
+      return new NetEConst(res);
+}
+
 NetEConst* NetEBComp::eval_eqeq_()
 {
       NetEConst*l = dynamic_cast<NetEConst*>(left_);
@@ -521,8 +587,15 @@ NetExpr* NetETernary::eval_tree()
 
 NetEConst* NetEUnary::eval_tree()
 {
-      NetExpr*oper = expr_->eval_tree();
-      NetEConst*rval = dynamic_cast<NetEConst*>(oper);
+      NetEConst*rval = dynamic_cast<NetEConst*>(expr_);
+      if (rval == 0) {
+	    NetExpr*oper = expr_->eval_tree();
+	    if (oper == 0) return 0;
+
+	    delete expr_;
+	    expr_ = oper;
+	    rval = dynamic_cast<NetEConst*>(oper);
+      }
 
       if (rval == 0)
 	    return 0;
@@ -555,14 +628,40 @@ NetEConst* NetEUnary::eval_tree()
 		return new NetEConst(out);
 	  }
 
+	  case '~': {
+		for (unsigned idx = 0 ;  idx < val.len() ;  idx += 1)
+		      switch (val.get(idx)) {
+			  case verinum::V0:
+			    val.set(idx, verinum::V1);
+			    break;
+			  case verinum::V1:
+			    val.set(idx, verinum::V0);
+			    break;
+			  default:
+			    val.set(idx, verinum::Vx);
+		      }
+
+		return new NetEConst(val);
+	  }
+
 	  default:
 	    delete rval;
 	    return 0;
       }
 }
 
+
+NetEConst* NetEUBits::eval_tree()
+{
+      return NetEUnary::eval_tree();
+}
+
+
 /*
  * $Log: eval_tree.cc,v $
+ * Revision 1.17  2001/01/02 03:23:40  steve
+ *  Evaluate constant &, | and unary ~.
+ *
  * Revision 1.16  2001/01/01 21:49:33  steve
  *  Fix shift and ternary operators in parameter expressions (PR#86)
  *
diff --git a/netlist.h b/netlist.h
index 8b052f748..a63ade472 100644
--- a/netlist.h
+++ b/netlist.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: netlist.h,v 1.188 2000/12/16 19:03:30 steve Exp $"
+#ident "$Id: netlist.h,v 1.189 2001/01/02 03:23:40 steve Exp $"
 #endif
 
 /*
@@ -2141,6 +2141,7 @@ class NetEBBits : public NetEBinary {
 
       virtual bool set_width(unsigned w);
       virtual NetEBBits* dup_expr() const;
+      virtual NetEConst* eval_tree();
 
       virtual NetNet* synthesize(Design*);
 };
@@ -2432,6 +2433,7 @@ class NetEUBits : public NetEUnary {
 
       virtual NetNet* synthesize(Design*);
 
+      virtual NetEConst* eval_tree();
 };
 
 class NetEUReduce : public NetEUnary {
@@ -2838,6 +2840,9 @@ extern ostream& operator << (ostream&, NetNet::Type);
 
 /*
  * $Log: netlist.h,v $
+ * Revision 1.189  2001/01/02 03:23:40  steve
+ *  Evaluate constant &, | and unary ~.
+ *
  * Revision 1.188  2000/12/16 19:03:30  steve
  *  Evaluate <= and ?: in parameter expressions (PR#81)
  *
diff --git a/verinum.cc b/verinum.cc
index 810b0589e..90494b65b 100644
--- a/verinum.cc
+++ b/verinum.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: verinum.cc,v 1.21 2000/12/10 22:01:36 steve Exp $"
+#ident "$Id: verinum.cc,v 1.22 2001/01/02 03:23:40 steve Exp $"
 #endif
 
 # include  "verinum.h"
@@ -548,8 +548,37 @@ verinum operator * (const verinum&left, const verinum&right)
       return result;
 }
 
+verinum::V operator | (verinum::V l, verinum::V r)
+{
+      if (l == verinum::V1)
+	    return verinum::V1;
+      if (r == verinum::V1)
+	    return verinum::V1;
+      if (l != verinum::V0)
+	    return verinum::Vx;
+      if (r != verinum::V0)
+	    return verinum::Vx;
+      return verinum::V0;
+}
+
+verinum::V operator & (verinum::V l, verinum::V r)
+{
+      if (l == verinum::V0)
+	    return verinum::V0;
+      if (r == verinum::V0)
+	    return verinum::V0;
+      if (l != verinum::V1)
+	    return verinum::Vx;
+      if (r != verinum::V1)
+	    return verinum::Vx;
+      return verinum::V1;
+}
+
 /*
  * $Log: verinum.cc,v $
+ * Revision 1.22  2001/01/02 03:23:40  steve
+ *  Evaluate constant &, | and unary ~.
+ *
  * Revision 1.21  2000/12/10 22:01:36  steve
  *  Support decimal constants in behavioral delays.
  *
@@ -585,38 +614,5 @@ verinum operator * (const verinum&left, const verinum&right)
  *
  * Revision 1.10  1999/10/10 23:29:37  steve
  *  Support evaluating + operator at compile time.
- *
- * Revision 1.9  1999/07/20 05:12:22  steve
- *  Implement the set method.
- *
- * Revision 1.8  1999/05/13 04:02:09  steve
- *  More precise handling of verinum bit lengths.
- *
- * Revision 1.7  1999/05/09 01:38:33  steve
- *  Add implementation of integer to verunum constructor.
- *
- * Revision 1.6  1998/12/20 02:05:41  steve
- *  Function to calculate wire initial value.
- *
- * Revision 1.5  1998/11/11 00:01:51  steve
- *  Check net ranges in declarations.
- *
- * Revision 1.4  1998/11/09 19:03:26  steve
- *  Oops, forgot return from operator<<
- *
- * Revision 1.3  1998/11/09 18:55:35  steve
- *  Add procedural while loops,
- *  Parse procedural for loops,
- *  Add procedural wait statements,
- *  Add constant nodes,
- *  Add XNOR logic gate,
- *  Make vvm output look a bit prettier.
- *
- * Revision 1.2  1998/11/07 17:04:48  steve
- *  Properly dump 0 length numbers.
- *
- * Revision 1.1  1998/11/03 23:29:07  steve
- *  Introduce verilog to CVS.
- *
  */
 
diff --git a/verinum.h b/verinum.h
index 50b87a4f7..e5b683573 100644
--- a/verinum.h
+++ b/verinum.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: verinum.h,v 1.13 2000/12/10 22:01:36 steve Exp $"
+#ident "$Id: verinum.h,v 1.14 2001/01/02 03:23:40 steve Exp $"
 #endif
 
 # include  <string>
@@ -100,6 +100,9 @@ class ostream;
 extern ostream& operator<< (ostream&, const verinum&);
 extern ostream& operator<< (ostream&, verinum::V);
 
+extern verinum::V operator | (verinum::V l, verinum::V r);
+extern verinum::V operator & (verinum::V l, verinum::V r);
+
 extern verinum::V operator == (const verinum&left, const verinum&right);
 extern verinum::V operator <= (const verinum&left, const verinum&right);
 extern verinum operator + (const verinum&left, const verinum&right);
@@ -111,6 +114,9 @@ extern verinum v_not(const verinum&left);
 
 /*
  * $Log: verinum.h,v $
+ * Revision 1.14  2001/01/02 03:23:40  steve
+ *  Evaluate constant &, | and unary ~.
+ *
  * Revision 1.13  2000/12/10 22:01:36  steve
  *  Support decimal constants in behavioral delays.
  *