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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 <iostream>
# include "PDelays.h"
# include "PExpr.h"
# include "verinum.h"
# include "netmisc.h"
bool dly_used_no_timescale = false;
bool dly_used_timescale = false;
bool display_ts_dly_warning = true;
PDelays::PDelays()
{
delete_flag_ = true;
for (unsigned idx = 0 ; idx < 3 ; idx += 1)
delay_[idx] = 0;
}
PDelays::~PDelays()
{
if (delete_flag_) {
for (unsigned idx = 0 ; idx < 3 ; idx += 1)
delete delay_[idx];
}
}
void PDelays::set_delay(PExpr*del)
{
assert(del);
assert(delay_[0] == 0);
delay_[0] = del;
delete_flag_ = true;
}
void PDelays::set_delays(const svector<PExpr*>*del, bool df)
{
assert(del);
assert(del->count() <= 3);
for (unsigned idx = 0 ; idx < del->count() ; idx += 1)
delay_[idx] = (*del)[idx];
delete_flag_ = df;
}
static NetExpr*calculate_val(Design*des, NetScope*scope, PExpr*expr)
{
ivl_variable_type_t tmp_type = IVL_VT_NO_TYPE;
bool tmp_flag = false;
expr->test_width(des, scope, 0, 0, tmp_type, tmp_flag);
NetExpr*dex = expr->elaborate_expr(des, scope, -1, false);
eval_expr(dex);
/* Print a warning if we find default and `timescale based
* delays in the design, since this is likely an error. */
if (scope->time_from_timescale()) dly_used_timescale = true;
else dly_used_no_timescale = true;
if (display_ts_dly_warning &&
dly_used_no_timescale && dly_used_timescale) {
cerr << "warning: Found both default and "
"`timescale based delays. Use" << endl;
cerr << " -Wtimescale to find the "
"module(s) with no `timescale." << endl;
display_ts_dly_warning = false;
}
/* If the delay expression is a real constant or vector
constant, then evaluate it, scale it to the local time
units, and return an adjusted value. */
if (NetECReal*tmp = dynamic_cast<NetECReal*>(dex)) {
verireal fn = tmp->value();
int shift = scope->time_unit() - des->get_precision();
int64_t delay = fn.as_long64(shift);
if (delay < 0)
delay = 0;
delete tmp;
NetEConst*tmp2 = new NetEConst(verinum(delay));
tmp2->set_line(*expr);
return tmp2;
}
if (NetEConst*tmp = dynamic_cast<NetEConst*>(dex)) {
verinum fn = tmp->value();
uint64_t delay = des->scale_to_precision(fn.as_ulong64(), scope);
delete tmp;
NetEConst*tmp2 = new NetEConst(verinum(delay));
tmp2->set_line(*expr);
return tmp2;
}
/* Oops, cannot evaluate down to a constant. */
return dex;
}
static NetExpr* make_delay_nets(Design*des, NetScope*scope, NetExpr*expr)
{
if (dynamic_cast<NetESignal*> (expr))
return expr;
if (dynamic_cast<NetEConst*> (expr))
return expr;
NetNet*sig = expr->synthesize(des, scope, expr);
if (sig == 0) {
cerr << expr->get_fileline() << ": error: Expression " << *expr
<< " is not suitable for delay expression." << endl;
return 0;
}
expr = new NetESignal(sig);
return expr;
}
static NetExpr* calc_decay_time(NetExpr *rise, NetExpr *fall)
{
NetEConst *c_rise = dynamic_cast<NetEConst*>(rise);
NetEConst *c_fall = dynamic_cast<NetEConst*>(fall);
if (c_rise && c_fall) {
if (c_rise->value() < c_fall->value()) return rise;
else return fall;
}
cerr << fall->get_fileline() << ": sorry: can not calculate the "
<< "decay time from " << *rise << " and " << *fall << endl;
return 0;
}
void PDelays::eval_delays(Design*des, NetScope*scope,
NetExpr*&rise_time,
NetExpr*&fall_time,
NetExpr*&decay_time,
bool as_nets_flag) const
{
assert(scope);
if (delay_[0]) {
rise_time = calculate_val(des, scope, delay_[0]);
if (as_nets_flag)
rise_time = make_delay_nets(des, scope, rise_time);
if (delay_[1]) {
fall_time = calculate_val(des, scope, delay_[1]);
if (as_nets_flag)
fall_time = make_delay_nets(des, scope, fall_time);
if (delay_[2]) {
decay_time = calculate_val(des, scope, delay_[2]);
if (as_nets_flag)
decay_time = make_delay_nets(des, scope,
decay_time);
} else {
// If this is zero then we need to do the min()
// at run time.
decay_time = calc_decay_time(rise_time, fall_time);
}
} else {
assert(delay_[2] == 0);
fall_time = rise_time;
decay_time = rise_time;
}
} else {
rise_time = 0;
fall_time = 0;
decay_time = 0;
}
}
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