diff --git a/elaborate.cc b/elaborate.cc
index 22742c0f3..4ef26dd24 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: elaborate.cc,v 1.210 2001/04/22 23:09:46 steve Exp $"
+#ident "$Id: elaborate.cc,v 1.211 2001/04/24 02:23:58 steve Exp $"
 #endif
 
 /*
@@ -612,8 +612,9 @@ void PGModule::elaborate_mod_(Design*des, Module*rmod, const string&path) const
 
 void PGModule::elaborate_udp_(Design*des, PUdp*udp, const string&path) const
 {
+      NetScope*scope = des->find_scope(path);
       const string my_name = path+"."+get_name();
-      NetUDP*net = new NetUDP(my_name, udp->ports.count(), udp);
+      NetUDP*net = new NetUDP(scope, my_name, udp->ports.count(), udp);
       net->set_attributes(udp->attributes);
 
 	/* Run through the pins, making netlists for the pin
@@ -2300,6 +2301,9 @@ Design* elaborate(const map<string,Module*>&modules,
 
 /*
  * $Log: elaborate.cc,v $
+ * Revision 1.211  2001/04/24 02:23:58  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.210  2001/04/22 23:09:46  steve
  *  More UDP consolidation from Stephan Boettcher.
  *
diff --git a/net_udp.cc b/net_udp.cc
index 2d2a63e3e..2fde00e78 100644
--- a/net_udp.cc
+++ b/net_udp.cc
@@ -18,13 +18,13 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: net_udp.cc,v 1.4 2001/04/22 23:09:46 steve Exp $"
+#ident "$Id: net_udp.cc,v 1.5 2001/04/24 02:23:58 steve Exp $"
 #endif
 
 # include  "netlist.h"
 
-NetUDP::NetUDP(const string&n, unsigned pins, PUdp *u)
-  : NetNode(n, pins), udp(u)
+NetUDP::NetUDP(NetScope*s, const string&n, unsigned pins, PUdp *u)
+  : NetNode(s, n, pins), udp(u)
 {
       pin(0).set_dir(Link::OUTPUT);
       pin(0).set_name("O", 0);
@@ -89,6 +89,9 @@ char NetUDP::get_initial() const
 
 /*
  * $Log: net_udp.cc,v $
+ * Revision 1.5  2001/04/24 02:23:58  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.4  2001/04/22 23:09:46  steve
  *  More UDP consolidation from Stephan Boettcher.
  *
diff --git a/netlist.h b/netlist.h
index 89f6d5bb4..b32767870 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 1.203 2001/04/22 23:09:46 steve Exp $"
+#ident "$Id: netlist.h,v 1.204 2001/04/24 02:23:58 steve Exp $"
 #endif
 
 /*
@@ -1067,7 +1067,7 @@ class NetLogic  : public NetNode {
 class NetUDP  : public NetNode {
 
     public:
-      explicit NetUDP(const string&n, unsigned pins, PUdp*u);
+      explicit NetUDP(NetScope*s, const string&n, unsigned pins, PUdp*u);
 
       virtual bool emit_node(struct target_t*) const;
       virtual void dump_node(ostream&, unsigned ind) const;
@@ -2802,6 +2802,9 @@ extern ostream& operator << (ostream&, NetNet::Type);
 
 /*
  * $Log: netlist.h,v $
+ * Revision 1.204  2001/04/24 02:23:58  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.203  2001/04/22 23:09:46  steve
  *  More UDP consolidation from Stephan Boettcher.
  *
diff --git a/t-dll.cc b/t-dll.cc
index cd9f7d93d..0f4637490 100644
--- a/t-dll.cc
+++ b/t-dll.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT) && !defined(macintosh)
-#ident "$Id: t-dll.cc,v 1.34 2001/04/22 23:09:46 steve Exp $"
+#ident "$Id: t-dll.cc,v 1.35 2001/04/24 02:23:58 steve Exp $"
 #endif
 
 # include  "compiler.h"
@@ -416,11 +416,15 @@ void dll_target::udp(const NetUDP*net)
       obj->type_ = IVL_LO_UDP;
 
       static map<string,ivl_udp_t> udps;
+      ivl_udp_t u;
 
-      ivl_udp_t u = udps[net->udp_name()];
-      if (!u)
+      if (udps.find(net->udp_name()) != udps.end())
 	{
-	  u = new ivl_udp_s;
+	  u = udps[net->udp_name()];
+	}
+      else
+	{
+	  u = new struct ivl_udp_s;
 	  u->nrows = net->rows();
 	  u->table = (char**)malloc((u->nrows+1)*sizeof(char*));
 	  assert(u->table);
@@ -439,6 +443,7 @@ void dll_target::udp(const NetUDP*net)
 		string tt = inp+out;
 		u->table[i++] = strdup(tt.c_str());
 	      } while (net->next(inp, out));
+	  assert(i==u->nrows);
 
 	  udps[net->udp_name()] = u;
 	}
@@ -806,6 +811,9 @@ extern const struct target tgt_dll = { "dll", &dll_target_obj };
 
 /*
  * $Log: t-dll.cc,v $
+ * Revision 1.35  2001/04/24 02:23:58  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.34  2001/04/22 23:09:46  steve
  *  More UDP consolidation from Stephan Boettcher.
  *
diff --git a/tgt-vvp/vvp_scope.c b/tgt-vvp/vvp_scope.c
index 7956b2f1b..8da1469d0 100644
--- a/tgt-vvp/vvp_scope.c
+++ b/tgt-vvp/vvp_scope.c
@@ -17,11 +17,12 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: vvp_scope.c,v 1.17 2001/04/21 02:04:01 steve Exp $"
+#ident "$Id: vvp_scope.c,v 1.18 2001/04/24 02:23:58 steve Exp $"
 #endif
 
 # include  "vvp_priv.h"
 # include  <assert.h>
+# include  <malloc.h>
 
 /*
  * The draw_scope function draws the major functional items within a
@@ -107,20 +108,91 @@ static void draw_net_in_scope(ivl_signal_t sig)
       fprintf(vvp_out, ";\n");
 }
 
+static void draw_udp_def(ivl_udp_t udp)
+{
+  unsigned init;
+  int i;
+
+  switch (ivl_udp_init(udp))
+    {
+    case '0':
+      init = 0;
+      break;
+    case '1':
+      init = 1;
+      break;
+    default:
+      init = 2;
+      break;
+    }
+
+  fprintf(vvp_out, 
+	  "UDP_%s .udp/%s \"%s\", %d, %d",
+	  ivl_udp_name(udp), 
+	  ivl_udp_sequ(udp) ? "sequ" : "comp",
+	  ivl_udp_name(udp),
+	  ivl_udp_nin(udp),
+	  init );
+
+  for (i=0; i<ivl_udp_rows(udp); i++)
+    fprintf(vvp_out, "\n ,\"%s\"", ivl_udp_row(udp, i) );
+
+  fprintf(vvp_out, ";\n");
+}
+
+static void draw_udp_in_scope(ivl_net_logic_t lptr)
+{
+  unsigned pdx;
+
+  ivl_udp_t udp = ivl_logic_udp(lptr);
+  
+  static ivl_udp_t *udps = 0x0;
+  static int nudps = 0;
+  int i;
+
+  for (i=0; i<nudps; i++)
+    if (udps[i] == udp)
+      break;
+  
+  if (i >= nudps)
+    {
+      udps = (ivl_udp_t*)realloc(udps, (nudps+1)*sizeof(ivl_udp_t));
+      assert(udps);
+      udps[nudps++] = udp;
+      draw_udp_def(udp);
+    }
+
+  fprintf(vvp_out, "L_%s .udp UDP_%s",
+	  ivl_logic_name(lptr), ivl_udp_name(udp));
+  
+  for (pdx = 1 ;  pdx < ivl_logic_pins(lptr) ;  pdx += 1) 
+    {
+      ivl_nexus_t nex = ivl_logic_pin(lptr, pdx);
+      fprintf(vvp_out, ", ");
+      draw_nexus_input(nex);
+    }
+  
+  fprintf(vvp_out, ";\n");
+}
+
 static void draw_logic_in_scope(ivl_net_logic_t lptr)
 {
 	    unsigned pdx;
       const char*ltype = "?";
       unsigned init_val = 0;
 
-	/* Skip BUFZ objects. Things that have a bufz as input
-	   will use the input to bufz instead. */
-      if (ivl_logic_type(lptr) == IVL_LO_BUFZ)
-	    return;
-
 
       switch (ivl_logic_type(lptr)) {
 
+          case IVL_LO_UDP:
+	    draw_udp_in_scope(lptr);
+	    return;
+
+          case IVL_LO_BUFZ:
+	/* Skip BUFZ objects. Things that have a bufz as input
+	   will use the input to bufz instead. */
+	    return;
+
 	  case IVL_LO_AND:
 	    ltype = "AND";
 	    init_val = 0x55;
@@ -314,6 +386,9 @@ int draw_scope(ivl_scope_t net, ivl_scope_t parent)
 
 /*
  * $Log: vvp_scope.c,v $
+ * Revision 1.18  2001/04/24 02:23:58  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.17  2001/04/21 02:04:01  steve
  *  Add NAND and XNOR functors.
  *
diff --git a/vvp/Makefile.in b/vvp/Makefile.in
index ea68676a2..243340d9d 100644
--- a/vvp/Makefile.in
+++ b/vvp/Makefile.in
@@ -16,7 +16,7 @@
 #    59 Temple Place - Suite 330
 #    Boston, MA 02111-1307, USA
 #
-#ident "$Id: Makefile.in,v 1.13 2001/04/01 21:31:46 steve Exp $"
+#ident "$Id: Makefile.in,v 1.14 2001/04/24 02:23:59 steve Exp $"
 #
 #
 SHELL = /bin/sh
@@ -61,7 +61,7 @@ V = vpi_modules.o vpi_const.o vpi_iter.o vpi_mcd.o vpi_priv.o \
 vpi_scope.o vpi_signal.o vpi_tasks.o vpi_time.o
 
 O = main.o parse.o parse_misc.o lexor.o compile.o functor.o symbols.o \
-codes.o vthread.o schedule.o tables.o $V
+codes.o vthread.o schedule.o tables.o udp.o $V
 
 vvp: $O
 	$(CXX) $(rdynamic) $(CXXFLAGS) $(LDFLAGS) -o vvp $O $(dllib)
diff --git a/vvp/compile.cc b/vvp/compile.cc
index c3e3a69c1..2f2679747 100644
--- a/vvp/compile.cc
+++ b/vvp/compile.cc
@@ -17,11 +17,12 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: compile.cc,v 1.38 2001/04/23 00:37:58 steve Exp $"
+#ident "$Id: compile.cc,v 1.39 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  "compile.h"
 # include  "functor.h"
+# include  "udp.h" 
 # include  "symbols.h"
 # include  "codes.h"
 # include  "schedule.h"
@@ -285,6 +286,97 @@ void compile_functor(char*label, char*type, unsigned init,
       free(type);
 }
 
+void compile_udp_def(int sequ, char *label, char *name,
+		     unsigned nin, unsigned init, char **table)
+{
+  struct vvp_udp_s *u = udp_create(label);
+  u->name = name;
+  u->sequ = sequ;
+  u->nin = nin;
+  u->init = init;
+  u->table = table;
+}
+
+char **compile_udp_table(char **table, char *row)
+{
+  if (table)
+    assert(strlen(*table)==strlen(row));
+
+  char **tt;
+  for (tt = table; tt && *tt; tt++);
+  int n = (tt-table) + 2;
+
+  table = (char**)realloc(table, n*sizeof(char*));
+  table[n-2] = row;
+  table[n-1] = 0x0;
+
+  return table;
+}
+
+void compile_udp_functor(char*label, char*type,
+			 unsigned argc, struct symb_s*argv)
+{
+  struct vvp_udp_s *u = udp_find(type);
+  assert (argc == u->nin);
+
+  int nfun = (argc-2) / 3 + 1;
+
+  vvp_ipoint_t fdx = functor_allocate(nfun);
+  functor_t obj = functor_index(fdx);
+
+  { 
+    symbol_value_t val;
+    val.num = fdx;
+    sym_set_value(sym_functors, label, val);
+  }
+
+  /* Run through the arguments looking for the functors that are
+     connected to my input ports. For each source functor that I
+     find, connect the output of that functor to the indexed
+     input by inserting myself (complete with the port number in
+     the vvp_ipoint_t) into the list that the source heads.
+     
+     If the source functor is not declared yet, then don't do
+     the link yet. Save the reference to be resolved later. */
+  
+  udp_init_links(fdx, u);
+  
+  udp_idx_t ux(fdx, u);
+  for (unsigned idx = 0;  idx < argc;  idx += 1) 
+    {
+      vvp_ipoint_t ifdx = ux.ipoint();
+      functor_t iobj = ux.functor();
+      ux.next();
+
+      symbol_value_t val = sym_get_value(sym_functors, argv[idx].text);
+      vvp_ipoint_t tmp = val.num;
+      
+      if (tmp) 
+	{
+	  tmp = ipoint_index(tmp, argv[idx].idx);
+	  functor_t fport = functor_index(tmp);
+	  iobj->port[ipoint_port(ifdx)] = fport->out;
+	  fport->out = ifdx;
+	  
+	  free(argv[idx].text);
+	} 
+      else 
+	{
+	  postpone_functor_input(ifdx, argv[idx].text, argv[idx].idx);
+	}
+    }
+  
+  obj->ival = 0xaa;
+  obj->old_ival = obj->ival;
+  obj->oval = u->init;
+  obj->mode = 3;
+  obj->udp = u;
+  
+  free(argv);
+  free(label);
+}
+
+
 void compile_event(char*label, char*type,
 		   unsigned argc, struct symb_s*argv)
 {
@@ -852,6 +944,9 @@ void compile_dump(FILE*fd)
 
 /*
  * $Log: compile.cc,v $
+ * Revision 1.39  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.38  2001/04/23 00:37:58  steve
  *  Support unconnected .net objects.
  *
diff --git a/vvp/compile.h b/vvp/compile.h
index a3aeb4590..ce29ac3ac 100644
--- a/vvp/compile.h
+++ b/vvp/compile.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: compile.h,v 1.16 2001/04/18 04:21:23 steve Exp $"
+#ident "$Id: compile.h,v 1.17 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  <stdio.h>
@@ -65,6 +65,19 @@ extern void compile_functor(char*label, char*type, unsigned init,
 extern void compile_vpi_symbol(const char*label, vpiHandle obj);
 extern vpiHandle compile_vpi_lookup(const char*label);
 
+/* 
+ * The first function creates a UDP, the second function adds table 
+   entries, and the third one instantiates a UDP functor.
+ */
+
+extern void compile_udp_def(int sequ, char*label, char *name,
+			    unsigned nin, unsigned init, char **table);
+
+extern void compile_udp_functor(char*label, char*type,
+				unsigned argc, struct symb_s*argv);
+
+extern char **compile_udp_table(char **table, char *row);
+
 /*
  * The compile_event function takes the parts of the event statement
  * and makes the various objects needed to simulate it. This includes
@@ -142,6 +155,9 @@ extern void compile_dump(FILE*fd);
 
 /*
  * $Log: compile.h,v $
+ * Revision 1.17  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.16  2001/04/18 04:21:23  steve
  *  Put threads into scopes.
  *
diff --git a/vvp/functor.cc b/vvp/functor.cc
index 4e93af267..a54ef64a8 100644
--- a/vvp/functor.cc
+++ b/vvp/functor.cc
@@ -17,10 +17,11 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: functor.cc,v 1.12 2001/04/18 04:21:23 steve Exp $"
+#ident "$Id: functor.cc,v 1.13 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  "functor.h"
+# include  "udp.h"
 # include  "schedule.h"
 # include  "vthread.h"
 # include  <assert.h>
@@ -213,6 +214,27 @@ static void functor_set_mode2(functor_t fp)
 	    schedule_assign(fp->out, 0, 0);
 }
 
+/*
+ * A mode-3 functor is a UDP.
+ */
+static void functor_set_mode3(vvp_ipoint_t ptr, functor_t fp)
+{
+  /* If we are down the tree, just propagate */
+  if (!fp->udp)
+    {
+      functor_propagate(ptr);
+      return;
+    }
+
+  unsigned char out = udp_propagate(ptr);
+
+  if (out != fp->oval) 
+    {
+      fp->oval = out;
+      functor_propagate(ptr);
+    }
+}
+
 /*
  * Set the addressed bit of the functor, and recalculate the
  * output. If the output changes any, then generate the necessary
@@ -223,7 +245,7 @@ void functor_set(vvp_ipoint_t ptr, unsigned bit, bool push)
       functor_t fp = functor_index(ptr);
       unsigned pp = ipoint_port(ptr);
       assert(fp);
-      assert(fp->table);
+      // assert(fp->table);
 
 	/* Change the bits of the input. */
       static const unsigned char mask_table[4] = { 0xfc, 0xf3, 0xcf, 0x3f };
@@ -240,6 +262,9 @@ void functor_set(vvp_ipoint_t ptr, unsigned bit, bool push)
 	  case 2:
 	    functor_set_mode2(fp);
 	    break;
+	  case 3:
+	    functor_set_mode3(ptr, fp);
+	    break;
       }
 }
 
@@ -306,6 +331,9 @@ const unsigned char ft_var[16] = {
 
 /*
  * $Log: functor.cc,v $
+ * Revision 1.13  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.12  2001/04/18 04:21:23  steve
  *  Put threads into scopes.
  *
diff --git a/vvp/functor.h b/vvp/functor.h
index 6bf6b0a31..a863db2db 100644
--- a/vvp/functor.h
+++ b/vvp/functor.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: functor.h,v 1.13 2001/04/21 02:04:01 steve Exp $"
+#ident "$Id: functor.h,v 1.14 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  "pointers.h"
@@ -82,6 +82,7 @@ struct functor_s {
       union {
 	    vvp_truth_t table;
 	    vvp_event_t event;
+	    struct vvp_udp_s *udp; // mode 3
       };
 
 	/* This is the output for the device. */
@@ -92,7 +93,11 @@ struct functor_s {
       unsigned char ival;
       unsigned char oval;
 	/* functor mode:  0 == table ;  1 == event ; 2 == named event */
+	/*                3 == udp                                    */
       unsigned char mode;
+      union {
+ 	    unsigned char old_ival; // mode 3
+      };
 };
 
 typedef struct functor_s *functor_t;
@@ -179,6 +184,9 @@ extern const unsigned char ft_var[];
 
 /*
  * $Log: functor.h,v $
+ * Revision 1.14  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.13  2001/04/21 02:04:01  steve
  *  Add NAND and XNOR functors.
  *
diff --git a/vvp/lexor.lex b/vvp/lexor.lex
index dcab38fd3..4091118a5 100644
--- a/vvp/lexor.lex
+++ b/vvp/lexor.lex
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: lexor.lex,v 1.13 2001/04/18 04:21:23 steve Exp $"
+#ident "$Id: lexor.lex,v 1.14 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  "parse_misc.h"
@@ -74,6 +74,9 @@
 ".thread"   { return K_THREAD; }
 ".var"      { return K_VAR; }
 ".var/s"    { return K_VAR_S; }
+".udp"         { return K_UDP; }
+".udp/c"(omb)? { return K_UDP_C; }
+".udp/s"(equ)? { return K_UDP_S; }
 
 
   /* instructions start with a % character. The compiler decides what
@@ -127,6 +130,9 @@ int yywrap()
 
 /*
  * $Log: lexor.lex,v $
+ * Revision 1.14  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.13  2001/04/18 04:21:23  steve
  *  Put threads into scopes.
  *
diff --git a/vvp/parse.y b/vvp/parse.y
index 87942720a..fceed9d36 100644
--- a/vvp/parse.y
+++ b/vvp/parse.y
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: parse.y,v 1.21 2001/04/23 00:37:58 steve Exp $"
+#ident "$Id: parse.y,v 1.22 2001/04/24 02:23:59 steve Exp $"
 #endif
 
 # include  "parse_misc.h"
@@ -37,6 +37,7 @@ extern FILE*yyin;
 
 %union {
       char*text;
+      char **table;
       long numb;
 
       comp_operands_t opa;
@@ -52,6 +53,7 @@ extern FILE*yyin;
 
 
 %token K_EVENT K_EVENT_OR K_FUNCTOR K_NET K_NET_S K_SCOPE K_THREAD
+%token K_UDP K_UDP_C K_UDP_S
 %token K_VAR K_VAR_S K_vpi_call K_disable K_fork
 %token K_vpi_module
 
@@ -66,6 +68,7 @@ extern FILE*yyin;
 %type <symbv> symbols symbols_net
 %type <text> label_opt
 %type <opa>  operand operands operands_opt
+%type <table> udp_table
 
 %type <argv> argument_opt argument_list
 %type <vpi>  argument
@@ -110,6 +113,21 @@ statement
 	| T_LABEL K_FUNCTOR T_SYMBOL','  T_NUMBER ';'
 		{ compile_functor($1, $3, $5, 0, 0); }
 
+
+  /* UDP statements define or instantiate UDPs.  Definitions take a 
+     label (UDP type id) a name (string), the number of inputs, and 
+     for sequentioal UDPs the initial value. */
+
+	| T_LABEL K_UDP_S T_STRING ',' T_NUMBER ',' T_NUMBER ',' udp_table ';'
+		{ compile_udp_def(1, $1, $3, $5, $7, $9); }
+
+	| T_LABEL K_UDP_C T_STRING ',' T_NUMBER ',' udp_table ';'
+		{ compile_udp_def(0, $1, $3, $5, 0, $7); }
+
+	| T_LABEL K_UDP T_SYMBOL ',' symbols ';'
+		{ compile_udp_functor($1, $3, $5.cnt, $5.vect); }
+
+
   /* Event statements take a label, a type (the first T_SYMBOL) and a
      list of inputs. If the type is instead a string, then we have a
      named event instead. */
@@ -341,6 +359,13 @@ symbol_opt
 		  $$.idx = 0;
 		}
 
+udp_table
+	: T_STRING
+		{ $$ = compile_udp_table(0x0, $1); }
+	| udp_table ',' T_STRING
+		{ $$ = compile_udp_table($1,  $3); }
+	;
+
 %%
 
 int compile_design(const char*path)
@@ -360,6 +385,9 @@ int compile_design(const char*path)
 
 /*
  * $Log: parse.y,v $
+ * Revision 1.22  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
  * Revision 1.21  2001/04/23 00:37:58  steve
  *  Support unconnected .net objects.
  *
diff --git a/vvp/udp.cc b/vvp/udp.cc
new file mode 100644
index 000000000..b34c0af0d
--- /dev/null
+++ b/vvp/udp.cc
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2000 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001 Stephan Boettcher <stephan@nevis.columbia.edu>
+ *
+ *    This source code is free software; you can redistribute it
+ *    and/or modify it in source code form under the terms of the GNU
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+#if !defined(WINNT)
+#ident "$Id: udp.cc,v 1.1 2001/04/24 02:23:59 steve Exp $"
+#endif
+
+#include "udp.h"
+#include "symbols.h"
+#include <assert.h>
+#include <malloc.h>
+
+static symbol_table_t udp_table;
+
+struct vvp_udp_s *udp_create(char *label)
+{
+  if (!udp_table)
+    udp_table = new_symbol_table();
+
+  assert(!udp_find(label));
+
+  struct vvp_udp_s *u = new struct vvp_udp_s;
+  
+  symbol_value_t v;
+  v.ptr = u;
+  sym_set_value(udp_table, label, v);
+
+  u->name = 0x0;
+  u->sequ = 0;
+  u->nin = 0;
+  u->init = 3;
+  u->table = 0x0;
+
+  return u;
+}
+
+struct vvp_udp_s *udp_find(char *label)
+{
+  symbol_value_t v = sym_get_value(udp_table, label);
+  return (struct vvp_udp_s *)v.ptr;
+}
+
+void udp_init_links(vvp_ipoint_t fdx, struct vvp_udp_s *u)
+{
+  udp_idx_t ux(fdx, u);
+  do
+    {
+      vvp_ipoint_t pa = ux.parent();
+      if (pa)
+	{
+	  functor_t fu = ux.functor();
+	  functor_t fp = functor_index(pa);
+	  fp->port[ipoint_port(pa)] = 0x0;
+	  fu->out = pa;
+	  fu->udp = 0x0;
+	  fu->mode = 3;
+	  
+	  fu->ival = 0xaa;
+	  fu->old_ival = fu->ival;
+	}
+    } while (ux.next_node());
+}
+
+unsigned char udp_propagate(vvp_ipoint_t uix)
+{
+  functor_t fu = functor_index(uix);
+  struct vvp_udp_s *u = fu->udp;
+  assert(u);
+  assert(u->table);
+
+  udp_idx_t ux(uix, u);
+
+  unsigned char ret = 2;
+
+  for (char **rptr = u->table; *rptr ; rptr++) 
+    {
+      char *row = *rptr;
+
+      if (u->sequ)
+	{
+	  if (row[0]=='?' || row[0]==(fu->oval&3)["01xx"])
+	    row++;
+	  else
+	    continue;
+	}
+
+      ux.reset();
+
+      do
+	{
+	  assert (*row);
+	  
+	  int port = ipoint_port(ux.ipoint());
+	  functor_t pfun = ux.functor();
+	  
+	  char new_bit = ((pfun->ival >> (2*port))&3)["01xx"];
+
+	  if (*row != new_bit  &&  *row != '?')
+	    {
+	      char old_bit = ((pfun->old_ival >> (2*port))&3)["01xx"];
+	      if (new_bit == old_bit)
+		break;
+
+	      switch (*row)
+		{
+		case '*':
+		  continue;
+		case '_':
+		  if (new_bit == '0')
+		    continue;
+		  break;
+		case '+':
+		  if (new_bit == '1')
+		    continue;
+		  break;
+		case '%':
+		  if (new_bit == 'x')
+		    continue;
+		  break;
+		case 'r':
+		  if (old_bit=='0' && new_bit=='1')
+		    continue;
+		  break;
+		case 'R':
+		  if (old_bit=='x' && new_bit=='1')
+		    continue;
+		  break;
+		case 'f':
+		  if (old_bit=='1' && new_bit=='0')
+		    continue;
+		  break;
+		case 'F':
+		  if (old_bit=='x' && new_bit=='0')
+		    continue;
+		  break;
+		case 'p':
+		  if (old_bit=='0')
+		    continue;
+		  break;
+		case 'n':
+		  if (old_bit=='1')
+		    continue;
+		  break;
+		case 'P':
+		  if (old_bit=='0' && new_bit=='x')
+		    continue;
+		  break;
+		case 'N':
+		  if (old_bit=='1' && new_bit=='x')
+		    continue;
+		  break;
+		}
+	      break;
+	    }
+	} while (row++, ux.next());
+      
+      if (ux.done())
+	{
+	  assert(*row);
+	  if (*row == '-')
+	    ret = fu->oval;
+	  else 
+	    switch (*row) 
+	      {
+	      case '0':
+		ret = 0;
+		break;
+	      case '1':
+		ret = 1;
+		break;
+	      default:
+		ret = 2;
+		break;
+	      }
+	  break;
+	}
+    }
+ 
+  ux.reset();
+  do
+    {
+      functor_t fu = ux.functor();
+      fu->old_ival = fu->ival;
+    } while (ux.next_node());
+  
+  return ret;
+}
+
+/*
+ * $Log: udp.cc,v $
+ * Revision 1.1  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
+ */
diff --git a/vvp/udp.h b/vvp/udp.h
new file mode 100644
index 000000000..373cfd2d8
--- /dev/null
+++ b/vvp/udp.h
@@ -0,0 +1,124 @@
+#ifndef __udp_H
+#define __udp_H
+/*
+ * Copyright (c) 2001 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2001 Stephan Boettcher <stephan@nevis.columbia.edu>
+ *
+ *    This source code is free software; you can redistribute it
+ *    and/or modify it in source code form under the terms of the GNU
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+#if !defined(WINNT)
+#ident "$Id: udp.h,v 1.1 2001/04/24 02:23:59 steve Exp $"
+#endif
+
+#include "pointers.h"
+#include "functor.h"
+#include "udp.h"
+
+struct vvp_udp_s 
+{
+  char *name;
+  unsigned short sequ;
+  unsigned short nin;
+  unsigned char  init;
+  char **table;
+};
+
+void udp_init_links(vvp_ipoint_t fdx, struct vvp_udp_s *u);
+struct vvp_udp_s *udp_create(char *label);
+struct vvp_udp_s *udp_find(char *label);
+unsigned char udp_propagate(vvp_ipoint_t);
+
+// The iterator through the input port list/tree/whatever
+
+class udp_idx_t
+{
+public:
+  udp_idx_t(vvp_ipoint_t, struct vvp_udp_s *);
+  vvp_ipoint_t ipoint();
+  functor_t functor();
+  bool next();
+  vvp_ipoint_t next_node();
+  bool done();
+  vvp_ipoint_t parent();
+  void reset();
+private:
+  vvp_ipoint_t root;
+  unsigned nin;
+  unsigned cur_i;
+};
+
+inline void udp_idx_t::reset()
+{
+  cur_i = 0;
+}
+
+inline udp_idx_t::udp_idx_t(vvp_ipoint_t idx, struct vvp_udp_s *u)
+  : root(idx), nin(u->nin)
+{
+  reset();
+}
+
+inline bool udp_idx_t::done()
+{
+  return cur_i >= nin;
+}
+
+inline bool udp_idx_t::next()
+{
+  cur_i++;
+  return !done();
+}
+
+inline vvp_ipoint_t udp_idx_t::ipoint()
+{
+  // The last node in the chain can hold 4 inputs.
+  int idx = (cur_i==nin-1 && cur_i ? cur_i-1 : cur_i) / 3;
+  int port = cur_i - 3*idx;
+  return ipoint_make(ipoint_index(root, idx), port);
+}
+
+inline functor_t udp_idx_t::functor()
+{
+  return functor_index(ipoint());
+}
+
+// junp to the next node, and return the ipoint.
+
+inline vvp_ipoint_t udp_idx_t::next_node()
+{
+  // We omit the last-node case, since is is a don't care here.
+  int idx = cur_i / 3 + 1;
+  cur_i = idx*3+1;
+  return cur_i < nin 
+    ? ipoint_make(ipoint_index(root, idx),0)
+    : 0;
+}
+
+inline vvp_ipoint_t udp_idx_t::parent()
+{
+  int idx = (cur_i==nin-1 ? cur_i-1 : cur_i) / 3;
+  if (!idx)
+    return 0x0;
+  return ipoint_make(ipoint_index(root, idx-1), 3);
+}
+
+/*
+ * $Log: udp.h,v $
+ * Revision 1.1  2001/04/24 02:23:59  steve
+ *  Support for UDP devices in VVP (Stephen Boettcher)
+ *
+ */
+#endif