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/*
* Copyright (c) 1999 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)
#ident "$Id: elab_expr.cc,v 1.15 2000/01/13 03:35:35 steve Exp $"
#endif


# include "pform.h"
# include "netlist.h"

/*
* Elaborate binary expressions. This involves elaborating the left
* and right sides, and creating one of a variety of different NetExpr
* types.
*/
NetExpr* PEBinary::elaborate_expr(Design*des, const string&path) const
{
      bool flag;
      NetExpr*lp = left_->elaborate_expr(des, path);
      NetExpr*rp = right_->elaborate_expr(des, path);
      if ((lp == 0) || (rp == 0)) {
delete lp;
delete rp;
return 0;
      }

/* If either expression can be evaluated ahead of time, then
do so. This can prove helpful later. */
      { NetExpr*tmp;
        tmp = lp->eval_tree();
if (tmp) {
delete lp;
lp = tmp;
}
tmp = rp->eval_tree();
if (tmp) {
delete rp;
rp = tmp;
}
      }

      NetEBinary*tmp;
      switch (op_) {
default:
tmp = new NetEBinary(op_, lp, rp);
tmp->set_line(*this);
break;

case 'a':
case 'o':
tmp = new NetEBLogic(op_, lp, rp);
tmp->set_line(*this);
break;

case '*':
tmp = new NetEBMult(op_, lp, rp);
tmp->set_line(*this);
break;

case 'l':
case 'r':
tmp = new NetEBShift(op_, lp, rp);
tmp->set_line(*this);
break;

case '^':
case '&':
case '|':
case 'O':
case 'X':
tmp = new NetEBBits(op_, lp, rp);
tmp->set_line(*this);
break;

case '+':
case '-':
tmp = new NetEBAdd(op_, lp, rp);
tmp->set_line(*this);
break;

case 'e': /* == */
case 'E': /* === */
case 'n': /* != */
case 'N': /* !== */
case 'L': /* <= */
case 'G': /* >= */
case '<':
case '>':
tmp = new NetEBComp(op_, lp, rp);
tmp->set_line(*this);
flag = tmp->set_width(1);
if (flag == false) {
cerr << get_line() << ": internal error: "
"expression bit width of comparison != 1." << endl;
des->errors += 1;
}
break;
      }

      return tmp;
}

NetESFunc* PECallFunction::elaborate_sfunc_(Design*des, const string&path) const
{
      cerr << get_line() << ": sorry: system functions not supported."
<< endl;
      des->errors += 1;
      return 0;
}

NetExpr* PECallFunction::elaborate_expr(Design*des, const string&path) const
{
      if (name_[0] == '$')
return elaborate_sfunc_(des, path);

      string myname = path+"."+name_;
      NetFuncDef*def = des->find_function(path, name_);
      if (def == 0) {
cerr << get_line() << ": error: No function " << name_ <<
" in this context (" << path << ")." << endl;
des->errors += 1;
return 0;
      }
      assert(def);
      svector<NetExpr*> parms (parms_.count());

      for (unsigned idx = 0 ; idx < parms.count() ; idx += 1) {
NetExpr*tmp = parms_[idx]->elaborate_expr(des, myname);
parms[idx] = tmp;
      }

/* Look for the return value signal for the called function in
the context of the function definition, not my context. */
      NetNet*res = des->find_signal(def->name(), name_);
      if (res == 0) {
cerr << get_line() << ": internal error: Unable to locate "
"function return value for " << name_ << " in " <<
def->name() << "." << endl;
des->errors += 1;
return 0;
      }

      assert(res);
      NetESignal*eres = new NetESignal(res);
      assert(eres);
      NetEUFunc*func = new NetEUFunc(def, eres, parms);
      return func;
}


NetExpr* PEConcat::elaborate_expr(Design*des, const string&path) const
{
      unsigned repeat = 1;

/* If there is a repeat expression, then evaluate the constant
value and set the repeat count. */
      if (repeat_) {
verinum*vrep = repeat_->eval_const(des, path);
if (vrep == 0) {
cerr << get_line() << ": error: "
"concatenation repeat expression cannot be evaluated."
<< endl;
des->errors += 1;
return 0;
}

repeat = vrep->as_ulong();
delete vrep;
      }

/* Make the empty concat expression. */
      NetEConcat*tmp = new NetEConcat(parms_.count(), repeat);
      tmp->set_line(*this);

/* Elaborate all the parameters and attach them to the concat node. */
      for (unsigned idx = 0 ; idx < parms_.count() ; idx += 1) {
assert(parms_[idx]);
NetExpr*ex = parms_[idx]->elaborate_expr(des, path);
if (ex == 0) continue;
ex->set_line(*parms_[idx]);
tmp->set(idx, ex);
      }

      return tmp;
}

NetExpr* PEIdent::elaborate_expr(Design*des, const string&path) const
{
// System identifiers show up in the netlist as identifiers.
      if (text_[0] == '$')
return new NetEIdent(text_, 64);

      string name = path+"."+text_;

// If the identifier name is a parameter name, then return
// a reference to the parameter expression.
      if (const NetExpr*ex = des->find_parameter(path, text_)) {
NetExpr*tmp;
if (dynamic_cast<const NetExpr*>(ex))
tmp = ex->dup_expr();
else
tmp = new NetEParam(des, path, text_);

tmp->set_line(*this);
return tmp;
      }

// If the identifier names a signal (a register or wire)
// then create a NetESignal node to handle it.
      if (NetNet*net = des->find_signal(path, text_)) {

// If this is a part select of a signal, then make a new
// temporary signal that is connected to just the
// selected bits.
if (lsb_) {
assert(msb_);
verinum*lsn = lsb_->eval_const(des, path);
verinum*msn = msb_->eval_const(des, path);
if ((lsn == 0) || (msn == 0)) {
cerr << get_line() << ": error: "
"Part select expresions must be "
"constant expressions." << endl;
des->errors += 1;
return 0;
}

assert(lsn);
assert(msn);
unsigned long lsv = lsn->as_ulong();
unsigned long msv = msn->as_ulong();
unsigned long wid = 1 + ((msv>lsv)? (msv-lsv) : (lsv-msv));
assert(wid <= net->pin_count());
assert(net->sb_to_idx(msv) >= net->sb_to_idx(lsv));

string tname = des->local_symbol(path);
NetTmp*tsig = new NetTmp(tname, wid);

// Connect the pins from the lsb up to the msb.
unsigned off = net->sb_to_idx(lsv);
for (unsigned idx = 0 ; idx < wid ; idx += 1)
connect(tsig->pin(idx), net->pin(idx+off));

NetESignal*tmp = new NetESignal(tsig);
tmp->set_line(*this);

des->add_signal(tsig);
return tmp;
}

// If the bit select is constant, then treat it similar
// to the part select, so that I save the effort of
// making a mux part in the netlist.
verinum*msn;
if (msb_ && (msn = msb_->eval_const(des, path))) {
assert(idx_ == 0);
unsigned long msv = msn->as_ulong();

string tname = des->local_symbol(path);
NetTmp*tsig = new NetTmp(tname);
connect(tsig->pin(0), net->pin(msv));
NetESignal*tmp = new NetESignal(tsig);
tmp->set_line(*this);

des->add_signal(tsig);
return tmp;
}

NetESignal*node = new NetESignal(net);
assert(idx_ == 0);

// Non-constant bit select? punt and make a subsignal
// device to mux the bit in the net.
if (msb_) {
NetExpr*ex = msb_->elaborate_expr(des, path);
NetESubSignal*ss = new NetESubSignal(node, ex);
ss->set_line(*this);
return ss;
}

// All else fails, return the signal itself as the
// expression.
assert(msb_ == 0);
return node;
      }

// If the identifier names a memory, then this is a
// memory reference and I must generate a NetEMemory
// object to handle it.
      if (NetMemory*mem = des->find_memory(path, text_)) {
if (msb_ == 0) {
NetEMemory*node = new NetEMemory(mem);
node->set_line(*this);
return node;
#if 0
cerr << get_line() << ": error: Memory ``" << name <<
"'' referenced without an index expression." << endl;
des->errors += 1;
return 0;
#endif
}
assert(msb_ != 0);
assert(lsb_ == 0);
assert(idx_ == 0);
NetExpr*i = msb_->elaborate_expr(des, path);
if (msb_ && i == 0) {
cerr << get_line() << ": error: Unable to exaborate "
"index expression `" << *msb_ << "'" << endl;
des->errors += 1;
return 0;
}

NetEMemory*node = new NetEMemory(mem, i);
node->set_line(*this);
return node;
      }

// Finally, if this is a scope name, then return that.
      if (NetScope*nsc = des->find_scope(text_)) {
NetEScope*tmp = new NetEScope(nsc);
tmp->set_line(*this);
return tmp;
      }

// I cannot interpret this identifier. Error message.
      cerr << get_line() << ": error: Unable to bind wire/reg/memory "
"`" << path << "." << text_ << "'" << endl;
      des->errors += 1;
      return 0;
}

/*
* Elaborate the Ternary operator. I know that the expressions were
* parsed so I can presume that they exist, and call elaboration
* methods. If any elaboration fails, then give up and return 0.
*/
NetExpr*PETernary::elaborate_expr(Design*des, const string&path) const
{
      assert(expr_);
      assert(tru_);
      assert(fal_);

      NetExpr*con = expr_->elaborate_expr(des, path);
      if (con == 0)
return 0;

      NetExpr*tru = tru_->elaborate_expr(des, path);
      if (tru == 0) {
delete con;
return 0;
      }

      NetExpr*fal = fal_->elaborate_expr(des, path);
      if (fal == 0) {
delete con;
delete tru;
return 0;
      }

      NetETernary*res = new NetETernary(con, tru, fal);
      return res;
}

/*
* $Log: elab_expr.cc,v $
* Revision 1.15 2000/01/13 03:35:35 steve
* Multiplication all the way to simulation.
*
* Revision 1.14 2000/01/01 06:18:00 steve
* Handle synthesis of concatenation.
*
* Revision 1.13 1999/12/12 06:03:14 steve
* Allow memories without indices in expressions.
*
* Revision 1.12 1999/11/30 04:54:01 steve
* Match scope names as last resort.
*
* Revision 1.11 1999/11/28 23:42:02 steve
* NetESignal object no longer need to be NetNode
* objects. Let them keep a pointer to NetNet objects.
*
* Revision 1.10 1999/11/27 19:07:57 steve
* Support the creation of scopes.
*
* Revision 1.9 1999/11/21 17:35:37 steve
* Memory name lookup handles scopes.
*
* Revision 1.8 1999/11/10 02:52:24 steve
* Create the vpiMemory handle type.
*
* Revision 1.7 1999/10/18 00:02:21 steve
* Catch unindexed memory reference.
*
* Revision 1.6 1999/09/30 02:43:02 steve
* Elaborate ~^ and ~| operators.
*
* Revision 1.5 1999/09/30 00:48:49 steve
* Cope with errors during ternary operator elaboration.
*
* Revision 1.4 1999/09/29 22:57:10 steve
* Move code to elab_expr.cc
*
* Revision 1.3 1999/09/25 02:57:30 steve
* Parse system function calls.
*
* Revision 1.2 1999/09/21 00:13:40 steve
* Support parameters that reference other paramters.
*
* Revision 1.1 1999/09/20 02:21:10 steve
* Elaborate parameters in phases.
*
*/
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