iverilog/netmisc.cc

/*
 * Copyright (c) 2001-2003 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: netmisc.cc,v 1.14 2007/06/02 03:42:13 steve Exp $"
#endif

# include "config.h"

# include  "netlist.h"
# include  "netmisc.h"
# include  "PExpr.h"
# include  "pform_types.h"
# include  "ivl_assert.h"

NetNet* add_to_net(Design*des, NetNet*sig, long val)
{
      if (val == 0)
	    return sig;
#if 0
      NetScope*scope = sig->scope();
      unsigned long abs_val = (val >= 0)? val : (-val);
      unsigned width = sig->pin_count();

      verinum val_v (abs_val, width);

      NetConst*val_c = new NetConst(scope, scope->local_symbol(), val_v);

      NetNet*val_s = new NetNet(scope, scope->local_symbol(),
			      NetNet::IMPLICIT, width);
      val_s->local_flag(true);

      NetNet*res = new NetNet(scope, scope->local_symbol(),
			      NetNet::IMPLICIT, width);
      res->local_flag(true);

      NetAddSub*add = new NetAddSub(scope, scope->local_symbol(), width);

      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
	    connect(sig->pin(idx), add->pin_DataA(idx));

      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
	    connect(val_c->pin(idx), add->pin_DataB(idx));

      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
	    connect(val_s->pin(idx), add->pin_DataB(idx));

      for (unsigned idx = 0 ;  idx < width ;  idx += 1)
	    connect(res->pin(idx), add->pin_Result(idx));

      if (val < 0)
	    add->attribute(perm_string::literal("LPM_Direction"), verinum("SUB"));
      else
	    add->attribute(perm_string::literal("LPM_Direction"), verinum("ADD"));

      des->add_node(add);
      des->add_node(val_c);

      return res;
#else
      cerr << sig->get_line() << ": XXXX: Forgot how to implement add_to_net" << endl;
      return 0;
#endif
}

/*
 * Add a signed constant to an existing expression. Generate a new
 * NetEBAdd node that has the input expression and an expression made
 * from the constant value.
 */
NetExpr* make_add_expr(NetExpr*expr, long val)
{
      if (val == 0)
	    return expr;

	// If the value to be added is <0, then instead generate a
	// SUBTRACT node and turn the value positive.
      char add_op = '+';
      if (val < 0) {
	    add_op = '-';
	    val = -val;
      }

      verinum val_v (val);
      val_v.has_sign(true);

      if (expr->has_width()) {
	    val_v = verinum(val_v, expr->expr_width());
      }

      NetEConst*val_c = new NetEConst(val_v);
      val_c->set_line(*expr);

      NetEBAdd*res = new NetEBAdd(add_op, expr, val_c);
      res->set_line(*expr);

      return res;
}

NetExpr* make_sub_expr(long val, NetExpr*expr)
{
      verinum val_v (val, expr->expr_width());
      val_v.has_sign(true);
      NetEConst*val_c = new NetEConst(val_v);
      val_c->set_line(*expr);

      NetEBAdd*res = new NetEBAdd('-', val_c, expr);
      res->set_line(*expr);

      return res;
}

NetExpr* elab_and_eval(Design*des, NetScope*scope,
		       const PExpr*pe, int expr_wid, int prune_width)
{
      NetExpr*tmp = pe->elaborate_expr(des, scope, expr_wid, false);
      if (tmp == 0)
	    return 0;

      if (NetExpr*tmp2 = tmp->eval_tree(prune_width)) {
	    delete tmp;
	    tmp = tmp2;
      }

      return tmp;
}

std::list<hname_t> eval_scope_path(Design*des, NetScope*scope,
				   const pform_name_t&path)
{
      list<hname_t> res;

      typedef pform_name_t::const_iterator pform_path_it;

      for (pform_path_it cur = path.begin() ; cur != path.end(); cur++) {
	    const name_component_t&comp = *cur;
	    if (comp.index.empty()) {
		  res.push_back(hname_t(comp.name));
		  continue;
	    }

	    assert(comp.index.size() == 1);
	    const index_component_t&index = comp.index.front();
	    assert(index.sel == index_component_t::SEL_BIT);

	    NetExpr*tmp = elab_and_eval(des, scope, index.msb, -1);
	    ivl_assert(*index.msb, tmp);

	    if (NetEConst*ctmp = dynamic_cast<NetEConst*>(tmp)) {
		  res.push_back(hname_t(comp.name, ctmp->value().as_long()));
		  delete ctmp;
		  continue;
	    }

	    return res;
      }

      return res;
}

/*
 * $Log: netmisc.cc,v $
 * Revision 1.14  2007/06/02 03:42:13  steve
 *  Properly evaluate scope path expressions.
 *
 * Revision 1.13  2007/03/08 05:30:03  steve
 *  Limit the calculated widths of constants.
 *
 * Revision 1.12  2006/06/02 04:48:50  steve
 *  Make elaborate_expr methods aware of the width that the context
 *  requires of it. In the process, fix sizing of the width of unary
 *  minus is context determined sizes.
 *
 * Revision 1.11  2005/04/08 04:50:31  steve
 *  Don not give to make_add express an unwanted width.
 *
 * Revision 1.10  2005/01/24 05:28:31  steve
 *  Remove the NetEBitSel and combine all bit/part select
 *  behavior into the NetESelect node and IVL_EX_SELECT
 *  ivl_target expression type.
 */