236 lines
6.7 KiB
C++
236 lines
6.7 KiB
C++
/*
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* Copyright (c) 1999 Stephen Williams (steve@icarus.com)
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*
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* This source code is free software; you can redistribute it
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* and/or modify it in source code form under the terms of the GNU
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* General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#ifdef HAVE_CVS_IDENT
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#ident "$Id: nodangle.cc,v 1.17 2002/08/12 01:35:00 steve Exp $"
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#endif
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# include "config.h"
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/*
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* This functor scans the design looking for dangling objects and
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* excess local signals. These deletions are not necessarily required
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* for proper functioning of anything, but they can clean up the
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* appearance of design files that are generated.
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*/
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# include "functor.h"
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# include "netlist.h"
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# include "compiler.h"
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class nodangle_f : public functor_t {
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public:
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void event(Design*des, NetEvent*ev);
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void signal(Design*des, NetNet*sig);
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unsigned count_;
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unsigned stotal, etotal;
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};
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void nodangle_f::event(Design*des, NetEvent*ev)
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{
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/* If there are no references to this event, then go right
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ahead and delete in. There is no use looking further at
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it. */
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if ((ev->nwait() + ev->ntrig()) == 0) {
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delete ev;
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etotal += 1;
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return;
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}
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/* Try to find all the events that are similar to me, and
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replace their references with references to me. */
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list<NetEvent*> match;
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ev->find_similar_event(match);
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for (list<NetEvent*>::iterator idx = match.begin()
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; idx != match.end() ; idx ++) {
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NetEvent*tmp = *idx;
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assert(tmp != ev);
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tmp ->replace_event(ev);
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}
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}
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void nodangle_f::signal(Design*des, NetNet*sig)
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{
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/* Cannot delete signals referenced in an expression
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or an l-value. */
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if (sig->get_refs() > 0)
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return;
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/* Cannot delete the ports of tasks or functions. There are
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too many places where they are referenced. */
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if ((sig->port_type() != NetNet::NOT_A_PORT)
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&& (sig->scope()->type() == NetScope::TASK))
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return;
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if ((sig->port_type() != NetNet::NOT_A_PORT)
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&& (sig->scope()->type() == NetScope::FUNC))
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return;
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/* Check to see if the signal is completely unconnected. If
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all the bits are unlinked, then delete it. */
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bool linked_flag = false;
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for (unsigned idx = 0 ; idx < sig->pin_count() ; idx += 1)
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if (sig->pin(idx).is_linked()) {
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linked_flag = true;
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break;
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}
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if (! linked_flag) {
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delete sig;
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stotal += 1;
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return;
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}
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/* The remaining things can only be done to synthesized
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signals, not ones that appear in the original Verilog. */
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if (! sig->local_flag())
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return;
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/* Check to see if there is some significant signal connected
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to every pin of this signal. */
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unsigned significant_flags = 0;
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for (unsigned idx = 0 ; idx < sig->pin_count() ; idx += 1) {
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Nexus*nex = sig->pin(idx).nexus();
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for (Link*cur = nex->first_nlink()
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; cur ; cur = cur->next_nlink()) {
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if (cur == &sig->pin(idx))
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continue;
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NetNet*cursig = dynamic_cast<NetNet*>(cur->get_obj());
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if (cursig == 0)
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continue;
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if (cursig->local_flag())
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continue;
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significant_flags += 1;
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break;
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}
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if (significant_flags <= idx)
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break;
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}
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/* If every pin is connected to another significant signal,
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then I can delete this one. */
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if (significant_flags == sig->pin_count()) {
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count_ += 1;
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delete sig;
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stotal += 1;
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}
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}
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void nodangle(Design*des)
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{
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nodangle_f fun;
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unsigned count_iterations = 0;
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fun.stotal = 0;
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fun.etotal = 0;
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do {
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fun.count_ = 0;
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des->functor(&fun);
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count_iterations += 1;
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if (verbose_flag) {
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cout << " ... " << count_iterations << " iterations"
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<< " deleted " << fun.stotal << " dangling signals"
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<< " and " << fun.etotal << " events."
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<< " (count=" << fun.count_ << ")" << endl;
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}
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} while (fun.count_ > 0);
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}
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/*
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* $Log: nodangle.cc,v $
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* Revision 1.17 2002/08/12 01:35:00 steve
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* conditional ident string using autoconfig.
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*
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* Revision 1.16 2002/07/24 16:24:45 steve
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* Rewrite find_similar_event to support doing
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* all event matching and replacement in one
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* shot, saving time in the scans.
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*
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* Revision 1.15 2002/05/26 01:39:02 steve
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* Carry Verilog 2001 attributes with processes,
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* all the way through to the ivl_target API.
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*
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* Divide signal reference counts between rval
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* and lval references.
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*
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* Revision 1.14 2002/02/02 06:13:38 steve
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* event find_similar should not find self.
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*
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* Revision 1.13 2001/07/27 02:41:55 steve
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* Fix binding of dangling function ports. do not elide them.
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*
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* Revision 1.12 2001/07/25 03:10:49 steve
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* Create a config.h.in file to hold all the config
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* junk, and support gcc 3.0. (Stephan Boettcher)
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*
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* Revision 1.11 2001/02/17 05:14:35 steve
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* Cannot elide task ports.
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*
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* Revision 1.10 2000/11/19 20:48:53 steve
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* Killing some signals might make others killable.
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*
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* Revision 1.9 2000/11/18 05:12:45 steve
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* Delete unreferenced signals no matter what.
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*
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* Revision 1.8 2000/06/25 19:59:42 steve
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* Redesign Links to include the Nexus class that
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* carries properties of the connected set of links.
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*
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* Revision 1.7 2000/05/31 02:26:49 steve
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* Globally merge redundant event objects.
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*
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* Revision 1.6 2000/05/07 04:37:56 steve
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* Carry strength values from Verilog source to the
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* pform and netlist for gates.
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*
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* Change vvm constants to use the driver_t to drive
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* a constant value. This works better if there are
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* multiple drivers on a signal.
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*
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* Revision 1.5 2000/04/28 21:00:29 steve
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* Over agressive signal elimination in constant probadation.
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*
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* Revision 1.4 2000/04/18 04:50:20 steve
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* Clean up unneeded NetEvent objects.
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*
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* Revision 1.3 2000/02/23 02:56:55 steve
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* Macintosh compilers do not support ident.
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*
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* Revision 1.2 1999/11/28 23:42:02 steve
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* NetESignal object no longer need to be NetNode
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* objects. Let them keep a pointer to NetNet objects.
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*
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* Revision 1.1 1999/11/18 03:52:20 steve
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* Turn NetTmp objects into normal local NetNet objects,
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* and add the nodangle functor to clean up the local
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* symbols generated by elaboration and other steps.
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*
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*/
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