iverilog/pad_to_width.cc

/*
 * Copyright (c) 1999-2000 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
 */
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: pad_to_width.cc,v 1.6 2001/02/15 06:59:36 steve Exp $"
#endif

# include  "netlist.h"
# include  "netmisc.h"

/*
 * This funciton transforms an expression by padding the high bits
 * with V0 until the expression has the desired width. This may mean
 * not transforming the expression at all, if it is already wide
 * enough.
 */
NetExpr*pad_to_width(NetExpr*expr, unsigned wid)
{
      if (wid > expr->expr_width()) {
	    verinum pad(verinum::V0, wid - expr->expr_width());
	    NetEConst*co = new NetEConst(pad);
	    co->set_line(*expr);
	    NetEConcat*cc = new NetEConcat(2);
	    cc->set_line(*expr);
	    cc->set(0, co);
	    cc->set(1, expr);
	    cc->set_width(wid);
	    expr = cc;
      }
      return expr;
}

NetNet*pad_to_width(Design*des, NetNet*net, unsigned wid)
{
      NetScope*scope = net->scope();
      const string path = scope->name();
      assert(scope);

      if (net->pin_count() >= wid)
	    return net;

      verinum pad(verinum::V0, wid - net->pin_count());
      NetConst*con = new NetConst(path + scope->local_symbol(), pad);
      des->add_node(con);

      NetNet*tmp = new NetNet(scope, path + scope->local_symbol(),
			      NetNet::WIRE, wid);
      tmp->local_flag(true);

      for (unsigned idx = 0 ;  idx < net->pin_count() ;  idx += 1)
	    connect(tmp->pin(idx), net->pin(idx));
      for (unsigned idx = net->pin_count() ;  idx < wid ;  idx += 1)
	    connect(tmp->pin(idx), con->pin(idx-net->pin_count()));

      return tmp;
}

/*
 * $Log: pad_to_width.cc,v $
 * Revision 1.6  2001/02/15 06:59:36  steve
 *  FreeBSD port has a maintainer now.
 *
 * Revision 1.5  2000/05/02 00:58:12  steve
 *  Move signal tables to the NetScope class.
 *
 * Revision 1.4  2000/02/23 02:56:55  steve
 *  Macintosh compilers do not support ident.
 *
 * Revision 1.3  2000/02/16 03:58:27  steve
 *  Fix up width matching in structural bitwise operators.
 *
 * Revision 1.2  2000/01/01 06:17:25  steve
 *  Propogate line number information when expanding expressions.
 *
 * Revision 1.1  1999/09/29 00:42:51  steve
 *  Allow expanding of additive operators.
 *
 */