mirror of
https://github.com/steveicarus/iverilog.git
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Cary R
0fc10d0262
This is a slightly modified version of the patch from the development branch. Specifically it only allows outputs in the sensitivity list for non-synthesis back ends. The text from the development patch follows. @* was only expanding to input nets. nex_input() for blocks was removing any output net that was also an input. There was also a bug in how output nets were removed. Only outputs currently defined were removed from the input list. always @(*) begin y = a; z = y; end would report "a" as an input. While always @(*) begin z = y; y = a; end would report both "a" and "y" as inputs. To fix this all nex_inputs now take a flag that when true (the default) correctly removes any output from the input list. Both the above cases will now return "a". If the flag is false outputs which are also inputs will be included in the input list. This is what the @* elaboration code uses to get the correct sensitivity list.
448 lines
11 KiB
C++
448 lines
11 KiB
C++
/*
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* Copyright (c) 2002 Stephen Williams ([email protected])
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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: net_nex_input.cc,v 1.12.2.1 2006/05/21 21:58:47 steve Exp $"
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#endif
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# include "config.h"
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# include <iostream>
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# include <cassert>
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# include <typeinfo>
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# include "netlist.h"
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# include "netmisc.h"
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NexusSet* NetExpr::nex_input(bool rem_out)
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{
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cerr << get_line()
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<< ": internal error: nex_input not implemented: "
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<< *this << endl;
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return 0;
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}
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NexusSet* NetProc::nex_input(bool rem_out)
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{
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cerr << get_line()
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<< ": internal error: NetProc::nex_input not implemented"
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<< endl;
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return 0;
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}
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NexusSet* NetEBinary::nex_input(bool rem_out)
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{
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NexusSet*result = left_->nex_input(rem_out);
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NexusSet*tmp = right_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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NexusSet* NetEBitSel::nex_input(bool rem_out)
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{
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NexusSet*result = sig_->nex_input(rem_out);
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NexusSet*tmp = idx_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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NexusSet* NetEConcat::nex_input(bool rem_out)
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{
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NexusSet*result = parms_[0]->nex_input(rem_out);
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for (unsigned idx = 1 ; idx < parms_.count() ; idx += 1) {
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NexusSet*tmp = parms_[idx]->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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/*
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* A constant has not inputs, so always return an empty set.
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*/
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NexusSet* NetEConst::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetECReal::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetEMemory::nex_input(bool rem_out)
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{
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NexusSet*result = idx_->nex_input(rem_out);
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return result;
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}
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/*
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* A parameter by definition has no inputs. It represents a constant
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* value, even if that value is a constant expression.
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*/
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NexusSet* NetEParam::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetEEvent::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetEScope::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetESelect::nex_input(bool rem_out)
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{
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NexusSet*result = base_? base_->nex_input(rem_out) : new NexusSet();
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NexusSet*tmp = expr_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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NexusSet* NetESFunc::nex_input(bool rem_out)
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{
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if (nparms_ == 0)
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return new NexusSet;
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NexusSet*result = parms_[0]->nex_input(rem_out);
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for (unsigned idx = 1 ; idx < nparms_ ; idx += 1) {
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NexusSet*tmp = parms_[idx]->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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NexusSet* NetESignal::nex_input(bool rem_out)
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{
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NexusSet*result = new NexusSet;
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assert(msi_ <= net_->pin_count());
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for (unsigned idx = lsi_ ; idx <= msi_ ; idx += 1)
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result->add(net_->pin(idx).nexus());
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return result;
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}
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NexusSet* NetETernary::nex_input(bool rem_out)
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{
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NexusSet*tmp;
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NexusSet*result = cond_->nex_input(rem_out);
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tmp = true_val_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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tmp = false_val_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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NexusSet* NetEUFunc::nex_input(bool rem_out)
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{
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NexusSet*result = new NexusSet;
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for (unsigned idx = 0 ; idx < parms_.count() ; idx += 1) {
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NexusSet*tmp = parms_[idx]->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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NexusSet* NetEUnary::nex_input(bool rem_out)
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{
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return expr_->nex_input(rem_out);
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}
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NexusSet* NetEVariable::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetAssign_::nex_input(bool rem_out)
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{
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if (bmux_ == 0)
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return new NexusSet;
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else
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return bmux_->nex_input(rem_out);
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}
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NexusSet* NetAssignBase::nex_input(bool rem_out)
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{
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NexusSet*result = rval_->nex_input(rem_out);
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/* It is possible that the lval_ can hav nex_input values. In
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particular, index expressions are statement inputs as well,
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so should be addressed here. */
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for (NetAssign_*cur = lval_ ; cur ; cur = cur->more) {
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NexusSet*tmp = cur->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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/*
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* The nex_input of a begin/end block is the NexusSet of bits that the
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* block reads from outside the block. That means it is the union of
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* the nex_input for all the substatements.
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*
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* The input set for a sequential set is not exactly the union of the
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* input sets because there is the possibility of intermediate values,
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* that don't deserve to be in the input set. To wit:
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*
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* begin
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* t = a + b;
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* c = ~t;
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* end
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*
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* In this example, "t" should not be in the input set because it is
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* used by the sequence as a temporary value.
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*/
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NexusSet* NetBlock::nex_input(bool rem_out)
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{
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if (last_ == 0)
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return new NexusSet;
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if (type_ == PARA) {
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cerr << get_line() << ": internal error: Sorry, "
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<< "I don't know how to synthesize fork/join blocks."
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<< endl;
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return 0;
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}
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NetProc*cur = last_->next_;
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/* This is the accumulated input set. */
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NexusSet*result = new NexusSet;
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/* This is an accumulated output set. */
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NexusSet*prev = new NexusSet;
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do {
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/* Get the inputs for the current statement. */
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NexusSet*tmp = cur->nex_input(rem_out);
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/* Add the current input set to the accumulated input set. */
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result->add(*tmp);
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delete tmp;
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/* Add the current outputs to the accumulated output set,
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so they can be removed from the input set below. */
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cur->nex_output(*prev);
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cur = cur->next_;
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} while (cur != last_->next_);
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/* Remove from the input set those bits that are outputs
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from other statements. They aren't really inputs
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to the block, just internal intermediate values. */
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if (rem_out) result->rem(*prev);
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return result;
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}
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/*
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* The inputs to a case statement are the inputs to the expression,
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* the inputs to all the guards, and the inputs to all the guarded
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* statements.
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*/
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NexusSet* NetCase::nex_input(bool rem_out)
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{
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NexusSet*result = expr_->nex_input(rem_out);
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if (result == 0)
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return 0;
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for (unsigned idx = 0 ; idx < nitems_ ; idx += 1) {
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/* Skip cases that have empty statements. */
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if (items_[idx].statement == 0)
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continue;
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NexusSet*tmp = items_[idx].statement->nex_input(rem_out);
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assert(tmp);
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result->add(*tmp);
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delete tmp;
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/* Usually, this is the guard expression. The default
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case is special and is identified by a null
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guard. The default guard obviously has no input. */
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if (items_[idx].guard) {
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tmp = items_[idx].guard->nex_input(rem_out);
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assert(tmp);
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result->add(*tmp);
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delete tmp;
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}
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}
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return result;
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}
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NexusSet* NetCAssign::nex_input(bool rem_out)
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{
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cerr << get_line() << ": internal warning: NetCAssign::nex_input()"
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<< " not implemented." << endl;
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return new NexusSet;
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}
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NexusSet* NetCondit::nex_input(bool rem_out)
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{
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NexusSet*result = expr_->nex_input(rem_out);
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if (if_ != 0) {
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NexusSet*tmp = if_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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if (else_ != 0) {
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NexusSet*tmp = else_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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NexusSet* NetForce::nex_input(bool rem_out)
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{
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cerr << get_line() << ": internal warning: NetForce::nex_input()"
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<< " not implemented." << endl;
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return new NexusSet;
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}
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NexusSet* NetForever::nex_input(bool rem_out)
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{
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NexusSet*result = statement_->nex_input(rem_out);
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return result;
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}
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/*
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* The NetPDelay statement is a statement of the form
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*
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* #<expr> <statement>
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*
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* The nex_input set is the input set of the <statement>. Do *not*
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* include the input set of the <expr> because it does not affect the
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* result.
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*/
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NexusSet* NetPDelay::nex_input(bool rem_out)
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{
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NexusSet*result = statement_->nex_input(rem_out);
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return result;
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}
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NexusSet* NetRepeat::nex_input(bool rem_out)
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{
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NexusSet*result = statement_->nex_input(rem_out);
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NexusSet*tmp = expr_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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NexusSet* NetSTask::nex_input(bool rem_out)
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{
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if (parms_.count() == 0)
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return new NexusSet;
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NexusSet*result = parms_[0]->nex_input(rem_out);
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for (unsigned idx = 1 ; idx < parms_.count() ; idx += 1) {
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NexusSet*tmp = parms_[idx]->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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}
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return result;
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}
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/*
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* The NetUTask represents a call to a user defined task. There are no
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* parameters to consider, because the compiler already removed them
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* and converted them to blocking assignments.
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*/
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NexusSet* NetUTask::nex_input(bool rem_out)
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{
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return new NexusSet;
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}
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NexusSet* NetWhile::nex_input(bool rem_out)
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{
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NexusSet*result = proc_->nex_input(rem_out);
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NexusSet*tmp = cond_->nex_input(rem_out);
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result->add(*tmp);
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delete tmp;
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return result;
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}
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/*
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* $Log: net_nex_input.cc,v $
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* Revision 1.12.2.1 2006/05/21 21:58:47 steve
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* NetESignal input is only selected bits.
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*
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* Revision 1.12 2004/09/04 04:24:15 steve
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* PR1026: assignment statements can have sensitivities in the l-values.
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*
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* Revision 1.11 2003/10/26 04:50:46 steve
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* Case with empty statements has no inputs.
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*
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* Revision 1.10 2003/07/26 03:34:42 steve
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* Start handling pad of expressions in code generators.
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*
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* Revision 1.9 2003/04/22 04:48:29 steve
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* Support event names as expressions elements.
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*
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* Revision 1.8 2003/01/26 21:15:58 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 1.7 2002/11/16 05:45:41 steve
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* Handle default: case in net_inputs for NetCase.
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*
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* Revision 1.6 2002/08/18 22:07:16 steve
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* Detect temporaries in sequential block synthesis.
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*
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* Revision 1.5 2002/08/12 01:34:59 steve
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* conditional ident string using autoconfig.
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*
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* Revision 1.4 2002/07/14 23:47:58 steve
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* Infinite loop in nex_input of NetBlock objects.
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*
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* Revision 1.3 2002/06/05 03:44:25 steve
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* Add support for memory words in l-value of
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* non-blocking assignments, and remove the special
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* NetAssignMem_ and NetAssignMemNB classes.
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*
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* Revision 1.2 2002/04/21 17:43:12 steve
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* implement nex_input for behavioral statements.
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*
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* Revision 1.1 2002/04/21 04:59:08 steve
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* Add support for conbinational events by finding
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* the inputs to expressions and some statements.
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* Get case and assignment statements working.
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*
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*/
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