Collect NetTran devices into islands.

NetTran devices must be collected into islands because they are all
a bi-directional mass. This is how vvp will process them and the code
generator will need a head start organizing them.

design_dump.cc

@@ -638,7 +638,8 @@ void NetTaskDef::dump(ostream&o, unsigned ind) const
 
 void NetTran::dump_node(ostream&o, unsigned ind) const
 {
-      o << setw(ind) << "" << type_ << " " << name() << endl;
+      o << setw(ind) << "" << type_ << " " << name()
+	<< " island " << island << endl;
       dump_node_pins(o, ind+4);
       dump_obj_attr(o, ind+4);
 }

elaborate.cc

@@ -864,6 +864,17 @@ void PGBuiltin::elaborate(Design*des, NetScope*scope) const
 	    }
 
       }
+
+	// If these new nodes can belong to an island, then run tests
+	// to joind islands now.
+      if (dynamic_cast<IslandBranch*> (cur[0])) {
+	    for (unsigned idx = 0 ; idx < count ; idx += 1) {
+		  join_island(cur[idx]);
+	    }
+      }
+
+	// "cur" is an array of pointers, and we don't need it any more.
+      delete[]cur;
 }
 
 NetNet*PGModule::resize_net_to_port_(Design*des, NetScope*scope,

ivl.def

@@ -224,6 +224,7 @@ ivl_switch_b
 ivl_switch_basename
 ivl_switch_enable
 ivl_switch_file
+ivl_switch_island
 ivl_switch_lineno
 ivl_switch_scope
 ivl_switch_type

ivl_target.h

@@ -80,6 +80,13 @@ _BEGIN_DECL
  *    processes. Structural expressions are instead treated as logic
  *    gates.
  *
+ * ivl_island_t
+ *    Certain types of objects may belong to islands. The island that
+ *    they belong to is represented by the ivl_island_t cookie. To
+ *    know if object belong to the same island, it is sufficient to
+ *    compare island cookies. If a==b, then island a is the same as
+ *    island b.
+ *
  * ivl_lpm_t
  *    This object is the base class for all the various LPM type
  *    device nodes. This object carries a few base properties
@@ -146,6 +153,7 @@ typedef struct ivl_delaypath_s*ivl_delaypath_t;
 typedef struct ivl_design_s   *ivl_design_t;
 typedef struct ivl_event_s    *ivl_event_t;
 typedef struct ivl_expr_s     *ivl_expr_t;
+typedef struct ivl_island_s   *ivl_island_t;
 typedef struct ivl_lpm_s      *ivl_lpm_t;
 typedef struct ivl_lval_s     *ivl_lval_t;
 typedef struct ivl_net_const_s*ivl_net_const_t;
@@ -713,6 +721,16 @@ extern unsigned ivl_file_table_index(const char *);
 extern unsigned ivl_file_table_size(void);
 
 
+/* ISLAND
+ *
+ * ivl_island_flag_set
+ * ivl_island_flag_test
+ *    Allow the user to test or set a boolean flag associated with the
+ *    island.
+ */
+extern int ivl_island_flag_set(ivl_island_t net, int flag, int value);
+extern int ivl_island_flag_test(ivl_island_t net, int flag);
+
 /* LOGIC
  * These types and functions support manipulation of logic gates. The
  * ivl_logic_t enumeration identifies the various kinds of gates that
@@ -1873,6 +1891,7 @@ extern const char*ivl_switch_basename(ivl_switch_t net);
 extern ivl_nexus_t ivl_switch_a(ivl_switch_t net);
 extern ivl_nexus_t ivl_switch_b(ivl_switch_t net);
 extern ivl_nexus_t ivl_switch_enable(ivl_switch_t net);
+extern ivl_island_t ivl_switch_island(ivl_switch_t net);
 
 /* Not implemented yet
 extern unsigned        ivl_switch_attr_cnt(ivl_switch_t net);

ivl_target_priv.h

@@ -0,0 +1,44 @@
+#ifndef __ivl_target_priv_H
+#define __ivl_target_H
+/*
+ * Copyright (c) 2008 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
+ *    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
+ */
+
+# include  <inttypes.h>
+
+/*
+* This deader has declarations related to the ivl_target.h API that
+* are not to be exported outside of the core via the ivl_target.h
+* interface.
+*/
+
+/*
+* Information about islands. Connected branches within a net are
+* collected into islands. Branches that are purely ddiscrete do not
+* have disciplines and do not belong to islands.
+*/
+
+class discipline_t;
+
+struct ivl_island_s {
+      discipline_t*discipline;
+	// user accessible flags. They are initially false, always.
+      vector<bool> flags;
+};
+
+#endif

net_tran.cc

@@ -26,6 +26,7 @@
 # include  "compiler.h"
 # include  "netlist.h"
 # include  "netmisc.h"
+# include  "ivl_target_priv.h"
 # include  "ivl_assert.h"
 
 static bool has_enable(ivl_switch_type_t tt)
@@ -55,3 +56,46 @@ NetTran::NetTran(NetScope*scope, perm_string n, ivl_switch_type_t tt)
 NetTran::~NetTran()
 {
 }
+
+void join_island(NetObj*obj)
+{
+      IslandBranch*branch = dynamic_cast<IslandBranch*> (obj);
+      if (branch == 0)
+	    return;
+
+      ivl_assert(*obj, branch->island == 0);
+      struct ivl_island_s*use_island = 0;
+
+      for (unsigned idx = 0 ; idx < obj->pin_count() ; idx += 1) {
+	    Nexus*nex = obj->pin(idx).nexus();
+	    for (Link*cur = nex->first_nlink() ; cur ; cur = cur->next_nlink()) {
+		  unsigned pin;
+		  NetObj*tmp;
+		  cur->cur_link(tmp, pin);
+		  if (tmp == obj)
+			continue;
+
+		  IslandBranch*tmp_branch = dynamic_cast<IslandBranch*> (tmp);
+		  if (tmp_branch == 0)
+			continue;
+
+		  ivl_assert(*tmp, tmp_branch->island);
+		  ivl_assert(*obj, use_island==0 || use_island==tmp_branch->island);
+		  use_island = tmp_branch->island;
+	    }
+      }
+
+      if (use_island == 0) {
+	    use_island = new ivl_island_s;
+	    use_island->discipline = 0;
+	    if (debug_elaborate)
+		  cerr << obj->get_fileline() << ": debug: "
+		       << "Create new island for this branch" << endl;
+      } else {
+	    if (debug_elaborate)
+		  cerr << obj->get_fileline() << ": debug: "
+		       << "Join this brach to existing island." << endl;
+      }
+
+      branch->island = use_island;
+}

netlist.h

@@ -52,6 +52,7 @@ class Nexus;
 class NetEvent;
 class NetNet;
 class NetNode;
+class NetObj;
 class NetProc;
 class NetProcTop;
 class NetRelease;
@@ -71,6 +72,8 @@ struct functor_t;
 
 ostream& operator << (ostream&o, ivl_variable_type_t val);
 
+extern void join_island(NetObj*obj);
+
 /* =========
  * A NetObj is anything that has any kind of behavior in the
  * netlist. Nodes can be gates, registers, etc. and are linked
@@ -131,6 +134,20 @@ class NetObj  : public Attrib, public virtual LineInfo {
       const NetExpr* delay3_;
 };
 
+/*
+* Objects that can be island branches are derived from this. (It is
+* possible for an object to be a NetObj and an IslandBranch.) This is
+* used to collect island information about the node.
+*/
+
+class IslandBranch {
+    public:
+      IslandBranch() : island(0) { }
+
+    public:
+      struct ivl_island_s* island;
+};
+
 class Link {
 
       friend void connect(Link&, Link&);
@@ -1359,7 +1376,7 @@ class NetSysFunc  : public NetNode {
       const struct sfunc_return_type*def_;
 };
 
-class NetTran  : public NetNode {
+class NetTran  : public NetNode, public IslandBranch {
 
     public:
       NetTran(NetScope*scope, perm_string n, ivl_switch_type_t type);

t-dll-api.cc

@@ -555,6 +555,28 @@ extern "C" unsigned ivl_file_table_size()
       return fn_vector.size();
 }
 
+extern "C" int ivl_island_flag_set(ivl_island_t net, int flag, int value)
+{
+      if (flag >= net->flags.size()) {
+	    if (value == 0)
+		  return 0;
+	    else
+		  net->flags.resize(flag+1, false);
+      }
+
+      int old_flag = net->flags[flag];
+      net->flags[flag] = value != 0;
+      return old_flag;
+}
+
+extern "C" int ivl_island_flag_test(ivl_island_t net, int flag)
+{
+      if (flag >= net->flags.size())
+	    return 0;
+      else
+	    return net->flags[flag];
+}
+
 extern "C" const char* ivl_logic_attr(ivl_net_logic_t net, const char*key)
 {
       assert(net);
@@ -2201,6 +2223,11 @@ extern "C" const char* ivl_switch_file(ivl_switch_t net)
       return net->file;
 }
 
+extern "C" ivl_island_t ivl_switch_island(ivl_switch_t net)
+{
+      return net->island;
+}
+
 extern "C" unsigned ivl_switch_lineno(ivl_switch_t net)
 {
       return net->lineno;

t-dll.cc

@@ -1039,7 +1039,9 @@ bool dll_target::tran(const NetTran*net)
       obj->type = net->type();
       obj->name = net->name();
       obj->scope = find_scope(des_, net->scope());
+      obj->island = net->island;
       assert(obj->scope);
+      assert(obj->island);
 
       const Nexus*nex;
 

t-dll.h

@@ -21,6 +21,7 @@
 
 # include  "target.h"
 # include  "ivl_target.h"
+# include  "ivl_target_priv.h"
 # include  "StringHeap.h"
 # include  "netlist.h"
 # include  <vector>
@@ -453,6 +454,7 @@ struct ivl_switch_s {
 
       perm_string name;
       ivl_scope_t scope;
+      ivl_island_t island;
 
       struct ivl_attribute_s*attr;
       unsigned nattr;