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/*
* Copyright (c) 1999-2009 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 "config.h"
# include "netlist.h"
# include "netmisc.h"
/*
* This function 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, const LineInfo&info)
{
if (wid <= expr->expr_width())
return expr;
/* If the expression is a const, then replace it with a wider
const. This is a more efficient result. */
if (NetEConst*tmp = dynamic_cast<NetEConst*>(expr)) {
verinum oval = pad_to_width(tmp->value(), wid);
tmp = new NetEConst(oval);
tmp->set_line(info);
delete expr;
return tmp;
}
NetESelect*tmp = new NetESelect(expr, 0, wid);
tmp->set_line(info);
tmp->cast_signed(expr->has_sign());
return tmp;
}
/*
* Pad a NetNet to the desired vector width by concatenating a
* NetConst of constant zeros. Use a NetConcat node to do the
* concatenation.
*/
NetNet*pad_to_width(Design*des, NetNet*net, unsigned wid, const LineInfo&info)
{
NetScope*scope = net->scope();
if (net->vector_width() >= wid)
return net;
// Make the NetConcat and connect the input net to the lsb input.
NetConcat*cc = new NetConcat(scope, scope->local_symbol(), wid, 2);
des->add_node(cc);
connect(cc->pin(1), net->pin(0));
// Make a NetConst of the desired width and connect in to the
// lsb input of the NetConcat.
verinum pad(verinum::V0, wid - net->vector_width());
NetConst*con = new NetConst(scope, scope->local_symbol(), pad);
des->add_node(con);
connect(cc->pin(2), con->pin(0));
// Make a NetNet for the NetConst to NetConcat link.
NetNet*tmp = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, wid - net->vector_width());
tmp->data_type( net->data_type() );
tmp->set_line(info);
tmp->local_flag(true);
connect(cc->pin(2), tmp->pin(0));
// Create a NetNet of the output width and connect it to the
// NetConcat node output pin.
tmp = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, wid);
tmp->data_type( net->data_type() );
tmp->set_line(info);
tmp->local_flag(true);
connect(cc->pin(0), tmp->pin(0));
return tmp;
}
NetNet*pad_to_width_signed(Design*des, NetNet*net, unsigned wid,
const LineInfo&info)
{
NetScope*scope = net->scope();
if (net->vector_width() >= wid)
return net;
NetSignExtend*se
= new NetSignExtend(scope, scope->local_symbol(), wid);
se->set_line(info);
des->add_node(se);
NetNet*tmp = new NetNet(scope, scope->local_symbol(), NetNet::WIRE, wid);
tmp->set_line(info);
tmp->local_flag(true);
tmp->data_type(net->data_type());
tmp->set_signed(true);
connect(tmp->pin(0), se->pin(0));
connect(se->pin(1), net->pin(0));
return tmp;
}
NetNet*crop_to_width(Design*des, NetNet*net, unsigned wid)
{
NetScope*scope = net->scope();
if (net->vector_width() <= wid)
return net;
NetPartSelect*ps = new NetPartSelect(net, 0, wid, NetPartSelect::VP);
des->add_node(ps);
ps->set_line(*net);
NetNet*tmp = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, wid);
tmp->data_type(net->data_type());
tmp->local_flag(true);
tmp->set_line(*net);
connect(ps->pin(0), tmp->pin(0));
return tmp;
}
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