net_link.cc

/*
 * Copyright (c) 2000 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
 */
#ifdef HAVE_CVS_IDENT
#ident "$Id: net_link.cc,v 1.21 2007/06/02 03:42:13 steve Exp $"
#endif

# include "config.h"

# include  <iostream>

# include  "netlist.h"
# include  <sstream>
# include  <cstring>
# include  <string>
# include  <typeinfo>
#ifdef HAVE_MALLOC_H
# include  <malloc.h>
#endif

void connect(Nexus*l, Link&r)
{
      assert(l);
      assert(r.nexus_);

      if (l == r.nexus_)
	    return;


      Nexus*tmp = r.nexus_;
      while (Link*cur = tmp->list_) {
	    tmp->list_ = cur->next_;
	    cur->nexus_ = 0;
	    cur->next_  = 0;
	    l->relink(cur);
      }

      l->driven_ = Nexus::NO_GUESS;

      assert(tmp->list_ == 0);
      delete tmp;
}

void connect(Link&l, Link&r)
{
      assert(&l != &r);
      if (r.is_linked() && !l.is_linked())
	    connect(r.nexus_, l);
      else
	    connect(l.nexus_, r);
}

Link::Link()
: dir_(PASSIVE), drive0_(STRONG), drive1_(STRONG), init_(verinum::Vx),
  inst_(0), next_(0), nexus_(0)
{
      (new Nexus()) -> relink(this);
}

Link::~Link()
{
      assert(nexus_);
      Nexus*tmp = nexus_;
      nexus_->unlink(this);
      if (tmp->list_ == 0)
	    delete tmp;
}

Nexus* Link::nexus()
{
      return nexus_;
}

const Nexus* Link::nexus() const
{
      return nexus_;
}

void Link::set_dir(DIR d)
{
      dir_ = d;
}

Link::DIR Link::get_dir() const
{
      return dir_;
}

void Link::drive0(Link::strength_t str)
{
      drive0_ = str;
}

void Link::drive1(Link::strength_t str)
{
      drive1_ = str;
}

Link::strength_t Link::drive0() const
{
      return drive0_;
}

Link::strength_t Link::drive1() const
{
      return drive1_;
}

void Link::set_init(verinum::V val)
{
      init_ = val;
}

verinum::V Link::get_init() const
{
      return init_;
}


void Link::cur_link(NetObj*&net, unsigned &pin)
{
      net = node_;
      pin = pin_;
}

void Link::cur_link(const NetObj*&net, unsigned &pin) const
{
      net = node_;
      pin = pin_;
}

void Link::unlink()
{
      assert(nexus_);
      if (! is_linked())
	    return;

      nexus_->unlink(this);
      (new Nexus()) -> relink(this);
}

bool Link::is_equal(const Link&that) const
{
      return (node_ == that.node_) && (pin_ == that.pin_);
}

bool Link::is_linked() const
{
      if (next_)
	    return true;
      if (nexus_->first_nlink() != this)
	    return true;

      return false;
}

bool Link::is_linked(const Link&that) const
{
      return nexus_ == that.nexus_;
}

Link* Link::next_nlink()
{
      return next_;
}

const Link* Link::next_nlink() const
{
      return next_;
}

const NetObj*Link::get_obj() const
{
      return node_;
}

NetObj*Link::get_obj()
{
      return node_;
}

unsigned Link::get_pin() const
{
      return pin_;
}

void Link::set_name(perm_string n, unsigned i)
{
      name_ = n;
      inst_ = i;
}

perm_string Link::get_name() const
{
      return name_;
}

unsigned Link::get_inst() const
{
      return inst_;
}

Nexus::Nexus()
{
      name_ = 0;
      list_ = 0;
      driven_ = NO_GUESS;
      t_cookie_ = 0;
}

Nexus::~Nexus()
{
      assert(list_ == 0);
      if (name_)
	    delete[]name_;
}

verinum::V Nexus::get_init() const
{
      assert(list_);
      for (Link*cur = list_ ;  cur ;  cur = cur->next_) {
	    if (cur->get_dir() == Link::OUTPUT)
		  return verinum::Vx;

	    if ((cur->get_dir() == Link::PASSIVE)
		&& (cur->get_init() != verinum::Vz))
		  return cur->get_init();
      }

      return verinum::Vz;
}

void Nexus::unlink(Link*that)
{
      if (name_) {
	    delete[] name_;
	    name_ = 0;
      }

	/* If the link I'm removing was a driver for this nexus, then
	   cancel my guess of the driven value. */
      if (that->get_dir() != Link::INPUT)
	    driven_ = NO_GUESS;

      assert(that);
      if (list_ == that) {
	    list_ = that->next_;
	    that->next_ = 0;
	    that->nexus_ = 0;
	    return;
      }

      Link*cur = list_;
      while (cur->next_ != that) {
	    assert(cur->next_);
	    cur = cur->next_;
      }

      cur->next_ = that->next_;
      that->nexus_ = 0;
      that->next_ = 0;
}

void Nexus::relink(Link*that)
{
      if (name_) {
	    delete[] name_;
	    name_ = 0;
      }

	/* If the link I'm adding is a driver for this nexus, then
	   cancel my guess of the driven value. */
      if (that->get_dir() != Link::INPUT)
	    driven_ = NO_GUESS;

      assert(that->nexus_ == 0);
      assert(that->next_ == 0);
      that->next_ = list_;
      that->nexus_ = this;
      list_ = that;
}

Link* Nexus::first_nlink()
{
      return list_;
}

const Link* Nexus::first_nlink() const
{
      return list_;
}

ivl_nexus_t Nexus::t_cookie() const
{
      return t_cookie_;
}

ivl_nexus_t Nexus::t_cookie(ivl_nexus_t val)const
{
      ivl_nexus_t tmp = t_cookie_;
      t_cookie_ = val;
      return tmp;
}

unsigned Nexus::vector_width() const
{
      for (const Link*cur = first_nlink() ; cur ; cur = cur->next_nlink()) {
	    const NetNet*sig = dynamic_cast<const NetNet*>(cur->get_obj());
	    if (sig == 0)
		  continue;

	    return sig->vector_width();
      }

      return 0;
}

NetNet* Nexus::pick_any_net()
{
      for (Link*cur = first_nlink() ; cur ; cur = cur->next_nlink()) {
	    NetNet*sig = dynamic_cast<NetNet*>(cur->get_obj());
	    if (sig != 0)
		  return sig;
      }

      return 0;
}

const char* Nexus::name() const
{
      if (name_)
	    return name_;

      const NetNet*sig = 0;
      unsigned pin = 0;
      for (const Link*cur = first_nlink()
		 ;  cur  ;  cur = cur->next_nlink()) {

	    const NetNet*cursig = dynamic_cast<const NetNet*>(cur->get_obj());
	    if (cursig == 0)
		  continue;

	    if (sig == 0) {
		  sig = cursig;
		  pin = cur->get_pin();
		  continue;
	    }

	    if ((cursig->pin_count() == 1) && (sig->pin_count() > 1))
		  continue;

	    if ((cursig->pin_count() > 1) && (sig->pin_count() == 1)) {
		  sig = cursig;
		  pin = cur->get_pin();
		  continue;
	    }

	    if (cursig->local_flag() && !sig->local_flag())
		  continue;

	    if (cursig->name() < sig->name())
		  continue;

	    sig = cursig;
	    pin = cur->get_pin();
      }

      if (sig == 0) {
	    const Link*lnk = first_nlink();
	    const NetObj*obj = lnk->get_obj();
	    pin = lnk->get_pin();
	    cerr << "internal error: No signal for nexus of " <<
		  obj->name() << " pin " << pin << "(" <<
		  lnk->get_name() << "<" << lnk->get_inst() << ">)"
		  " type=" << typeid(*obj).name() << "?" << endl;

      }
      assert(sig);
      ostringstream tmp;
      tmp << scope_path(sig->scope()) << "." << sig->name();
      if (sig->pin_count() > 1)
	    tmp << "<" << pin << ">";

      const string tmps = tmp.str();
      name_ = new char[strlen(tmps.c_str()) + 1];
      strcpy(name_, tmps.c_str());
      return name_;
}


NexusSet::NexusSet()
{
      items_ = 0;
      nitems_ = 0;
}

NexusSet::~NexusSet()
{
      if (nitems_ > 0) {
	    assert(items_ != 0);
	    delete[] items_;
      } else {
	    assert(items_ == 0);
      }
}

unsigned NexusSet::count() const
{
      return nitems_;
}

void NexusSet::add(Nexus*that)
{
      if (nitems_ == 0) {
	    assert(items_ == 0);
	    items_ = (Nexus**)malloc(sizeof(Nexus*));
	    items_[0] = that;
	    nitems_ = 1;
	    return;
      }

      unsigned ptr = bsearch_(that);
      if (ptr < nitems_) {
	    assert(items_[ptr] == that);
	    return;
      }

      assert(ptr == nitems_);

      items_ = (Nexus**)realloc(items_, (nitems_+1) * sizeof(Nexus*));
      items_[ptr] = that;
      nitems_ += 1;
}

void NexusSet::add(const NexusSet&that)
{
      for (unsigned idx = 0 ;  idx < that.nitems_ ;  idx += 1)
	    add(that.items_[idx]);
}

void NexusSet::rem(Nexus*that)
{
      if (nitems_ == 0)
	    return;

      unsigned ptr = bsearch_(that);
      if (ptr >= nitems_)
	    return;

      if (nitems_ == 1) {
	    free(items_);
	    items_ = 0;
	    nitems_ = 0;
	    return;
      }

      for (unsigned idx = ptr ;  idx < (nitems_-1) ;  idx += 1)
	    items_[idx] = items_[idx+1];

      items_ = (Nexus**)realloc(items_, (nitems_-1) * sizeof(Nexus*));
      nitems_ -= 1;
}

void NexusSet::rem(const NexusSet&that)
{
      for (unsigned idx = 0 ;  idx < that.nitems_ ;  idx += 1)
	    rem(that.items_[idx]);
}

Nexus* NexusSet::operator[] (unsigned idx) const
{
      assert(idx < nitems_);
      return items_[idx];
}

unsigned NexusSet::bsearch_(Nexus*that) const
{
      for (unsigned idx = 0 ;  idx < nitems_ ;  idx += 1) {
	    if (items_[idx] == that)
		  return idx;
      }

      return nitems_;
}

bool NexusSet::contains(const NexusSet&that) const
{
      for (unsigned idx = 0 ;  idx < that.nitems_ ;  idx += 1) {
	    unsigned where = bsearch_(that[idx]);
	    if (where == nitems_)
		  return false;
	    if (items_[where] != that[idx])
		  return false;
      }

      return true;
}

bool NexusSet::intersect(const NexusSet&that) const
{
      for (unsigned idx = 0 ;  idx < that.nitems_ ;  idx += 1) {
	    unsigned where = bsearch_(that[idx]);
	    if (where == nitems_)
		  continue;
	    if (items_[where] == that[idx])
		  return true;
      }

      return false;
}

/*
 * $Log: net_link.cc,v $
 * Revision 1.21  2007/06/02 03:42:13  steve
 *  Properly evaluate scope path expressions.
 *
 * Revision 1.20  2007/03/26 18:17:50  steve
 *  Remove pretense of general use for t_cookie.
 *
 * Revision 1.19  2006/02/02 02:43:58  steve
 *  Allow part selects of memory words in l-values.
 *
 * Revision 1.18  2005/09/25 23:40:11  steve
 *  Simplify NexusSet set handling.
 *
 * Revision 1.17  2005/06/13 23:22:37  steve
 *  Fix compile errors.
 *
 * Revision 1.16  2005/04/24 23:44:02  steve
 *  Update DFF support to new data flow.
 *
 * Revision 1.15  2005/01/09 20:16:01  steve
 *  Use PartSelect/PV and VP to handle part selects through ports.
 *
 * Revision 1.14  2004/02/18 17:11:56  steve
 *  Use perm_strings for named langiage items.
 *
 * Revision 1.13  2003/01/14 21:16:18  steve
 *  Move strstream to ostringstream for compatibility.
 *
 * Revision 1.12  2002/10/21 01:42:08  steve
 *  Synthesizer support for synchronous begin-end blocks.
 *
 * Revision 1.11  2002/08/18 22:07:16  steve
 *  Detect temporaries in sequential block synthesis.
 *
 * Revision 1.10  2002/08/12 01:34:59  steve
 *  conditional ident string using autoconfig.
 *
 * Revision 1.9  2002/07/03 03:08:47  steve
 *  Clear drive cache on link or unlink.
 *
 * Revision 1.8  2002/06/30 02:21:31  steve
 *  Add structure for asynchronous logic synthesis.
 *
 * Revision 1.7  2002/06/24 01:49:39  steve
 *  Make link_drive_constant cache its results in
 *  the Nexus, to improve cprop performance.
 *
 * Revision 1.6  2002/04/21 04:59:08  steve
 *  Add support for conbinational events by finding
 *  the inputs to expressions and some statements.
 *  Get case and assignment statements working.
 *
 * Revision 1.5  2001/07/25 03:10:49  steve
 *  Create a config.h.in file to hold all the config
 *  junk, and support gcc 3.0. (Stephan Boettcher)
 *
 * Revision 1.4  2000/10/06 23:46:50  steve
 *  ivl_target updates, including more complete
 *  handling of ivl_nexus_t objects. Much reduced
 *  dependencies on pointers to netlist objects.
 *
 * Revision 1.3  2000/08/26 00:54:03  steve
 *  Get at gate information for ivl_target interface.
 *
 * Revision 1.2  2000/07/14 06:12:57  steve
 *  Move inital value handling from NetNet to Nexus
 *  objects. This allows better propogation of inital
 *  values.
 *
 *  Clean up constant propagation  a bit to account
 *  for regs that are not really values.
 *
 * Revision 1.1  2000/06/25 19:59:42  steve
 *  Redesign Links to include the Nexus class that
 *  carries properties of the connected set of links.
 *
 */