196 lines
5.8 KiB
C++
196 lines
5.8 KiB
C++
/*
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* Copyright (c) 1999-2005 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: pad_to_width.cc,v 1.20 2005/12/22 15:43:47 steve Exp $"
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#endif
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# include "config.h"
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# include "netlist.h"
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# include "netmisc.h"
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/*
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* This function transforms an expression by padding the high bits
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* with V0 until the expression has the desired width. This may mean
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* not transforming the expression at all, if it is already wide
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* enough.
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*/
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NetExpr*pad_to_width(NetExpr*expr, unsigned wid)
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{
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if (wid <= expr->expr_width())
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return expr;
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/* If the expression is a const, then replace it with a wider
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const. This is a more efficient result. */
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if (NetEConst*tmp = dynamic_cast<NetEConst*>(expr)) {
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verinum eval = tmp->value();
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bool signed_flag = eval.has_sign();
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verinum::V pad = verinum::V0;
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if (signed_flag)
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pad = eval.get(eval.len()-1);
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verinum oval (pad, wid, eval.has_len());
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for (unsigned idx = 0 ; idx < eval.len() ; idx += 1)
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oval.set(idx, eval.get(idx));
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oval.has_sign(signed_flag);
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tmp = new NetEConst(oval);
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delete expr;
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return tmp;
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}
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NetESelect*tmp = new NetESelect(expr, 0, wid);
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tmp->set_line(*expr);
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tmp->cast_signed(expr->has_sign());
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return tmp;
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}
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/*
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* Pad a NetNet to the desired vector width by concatenating a
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* NetConst of constant zeros. Use a NetConcat node to do the
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* concatenation.
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*/
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NetNet*pad_to_width(Design*des, NetNet*net, unsigned wid)
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{
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NetScope*scope = net->scope();
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if (net->vector_width() >= wid)
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return net;
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// Make the NetConcat and connect the input net to the lsb input.
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NetConcat*cc = new NetConcat(scope, scope->local_symbol(), wid, 2);
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des->add_node(cc);
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connect(cc->pin(1), net->pin(0));
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// Make a NetConst of the desired width and connect in to the
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// lsb input of the NetConcat.
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verinum pad(verinum::V0, wid - net->vector_width());
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NetConst*con = new NetConst(scope, scope->local_symbol(), pad);
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des->add_node(con);
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connect(cc->pin(2), con->pin(0));
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// Make a NetNet for the NetConst to NetConcat link.
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NetNet*tmp = new NetNet(scope, scope->local_symbol(),
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NetNet::WIRE, wid - net->vector_width());
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tmp->data_type( net->data_type() );
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tmp->local_flag(true);
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connect(cc->pin(2), tmp->pin(0));
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// Create a NetNet of the output width and connect it to the
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// NetConcat node output pin.
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tmp = new NetNet(scope, scope->local_symbol(),
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NetNet::WIRE, wid);
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tmp->data_type( net->data_type() );
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tmp->local_flag(true);
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connect(cc->pin(0), tmp->pin(0));
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return tmp;
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}
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NetNet*pad_to_width_signed(Design*des, NetNet*net, unsigned wid)
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{
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NetScope*scope = net->scope();
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if (net->vector_width() >= wid)
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return net;
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NetSignExtend*se
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= new NetSignExtend(scope, scope->local_symbol(), wid);
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se->set_line(*net);
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des->add_node(se);
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NetNet*tmp = new NetNet(scope, scope->local_symbol(), NetNet::WIRE, wid);
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tmp->set_line(*net);
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tmp->local_flag(true);
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tmp->data_type(net->data_type());
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tmp->set_signed(true);
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connect(tmp->pin(0), se->pin(0));
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connect(se->pin(1), net->pin(0));
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return tmp;
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}
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NetNet*crop_to_width(Design*des, NetNet*net, unsigned wid)
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{
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NetScope*scope = net->scope();
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if (net->vector_width() <= wid)
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return net;
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NetPartSelect*ps = new NetPartSelect(net, 0, wid, NetPartSelect::VP);
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des->add_node(ps);
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ps->set_line(*net);
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NetNet*tmp = new NetNet(scope, scope->local_symbol(),
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NetNet::WIRE, wid);
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tmp->data_type(net->data_type());
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tmp->local_flag(true);
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tmp->set_line(*tmp);
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connect(ps->pin(0), tmp->pin(0));
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return tmp;
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}
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/*
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* $Log: pad_to_width.cc,v $
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* Revision 1.20 2005/12/22 15:43:47 steve
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* pad_to_width handles signed expressions.
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*
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* Revision 1.19 2005/07/07 16:22:49 steve
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* Generalize signals to carry types.
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*
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* Revision 1.18 2005/05/24 01:44:28 steve
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* Do sign extension of structuran nets.
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*
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* Revision 1.17 2005/04/24 23:44:02 steve
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* Update DFF support to new data flow.
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*
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* Revision 1.16 2005/01/12 03:17:37 steve
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* Properly pad vector widths in pgassign.
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*
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* Revision 1.15 2004/02/18 17:11:57 steve
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* Use perm_strings for named langiage items.
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*
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* Revision 1.14 2003/03/06 00:28:42 steve
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* All NetObj objects have lex_string base names.
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*
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* Revision 1.13 2003/01/27 05:09:17 steve
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* Spelling fixes.
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*
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* Revision 1.12 2003/01/26 21:15:59 steve
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* Rework expression parsing and elaboration to
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* accommodate real/realtime values and expressions.
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*
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* Revision 1.11 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 1.10 2002/05/25 16:43:22 steve
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* Better padding of constants.
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*
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* Revision 1.9 2001/10/28 01:14:53 steve
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* NetObj constructor finally requires a scope.
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*
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* Revision 1.8 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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