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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
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: PDelays.cc,v 1.11.2.1 2006/10/04 00:37:03 steve Exp $"
#endif
# include "config.h"
# include <iostream>
# include "PDelays.h"
# include "PExpr.h"
# include "verinum.h"
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 unsigned long calculate_val(Design*des, NetScope*scope,
const PExpr*expr)
{
NetExpr*dex = expr->elaborate_expr(des, scope);
if (NetExpr*tmp = dex->eval_tree()) {
delete dex;
dex = tmp;
}
int shift = scope->time_unit() - des->get_precision();
if (sizeof(unsigned) <= 4 && shift > 9) {
cerr << expr->get_line() << ": error: Precision overflow"
<< " in scope " << scope->name() << "." << endl;
cerr << expr->get_line() << ": :"
<< " Units are 10e" << scope->time_unit()
<< " minus precision 10e" << des->get_precision()
<< " is 10e" << shift << "." << endl;
cerr << expr->get_line() << ": : Perhaps a timescale "
<< "is missing or incorrect?" << endl;
des->errors += 1;
return 0;
}
/* 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();
long delay = fn.as_long(shift);
if (delay < 0)
delay = 0;
delete tmp;
return delay;
}
if (NetEConst*tmp = dynamic_cast<NetEConst*>(dex)) {
verinum fn = tmp->value();
unsigned long delay =
des->scale_to_precision(fn.as_ulong(), scope);
delete tmp;
return delay;
}
/* Oops, cannot evaluate down to a constant. Error message. */
delete dex;
cerr << expr->get_line() << ": sorry: non-constant "
<< "delays not supported here: " << *expr << endl;
des->errors += 1;
return 0;
}
void PDelays::eval_delays(Design*des, NetScope*scope,
unsigned long&rise_time,
unsigned long&fall_time,
unsigned long&decay_time) const
{
assert(scope);
if (delay_[0]) {
rise_time = calculate_val(des, scope, delay_[0]);
if (delay_[1]) {
fall_time = calculate_val(des, scope, delay_[1]);
if (delay_[2]) {
decay_time = calculate_val(des, scope, delay_[2]);
} else {
if (rise_time < fall_time)
decay_time = rise_time;
else
decay_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;
}
}
/*
* $Log: PDelays.cc,v $
* Revision 1.11.2.1 2006/10/04 00:37:03 steve
* Detect delay precision overflow.
*
* Revision 1.11 2003/06/21 01:21:42 steve
* Harmless fixup of warnings.
*
* Revision 1.10 2003/02/08 19:49:21 steve
* Calculate delay statement delays using elaborated
* expressions instead of pre-elaborated expression
* trees.
*
* Remove the eval_pexpr methods from PExpr.
*
* Revision 1.9 2002/08/12 01:34:58 steve
* conditional ident string using autoconfig.
*
* Revision 1.8 2001/12/29 20:19:31 steve
* Do not delete delay expressions of UDP instances.
*
* Revision 1.7 2001/11/22 06:20:59 steve
* Use NetScope instead of string for scope path.
*
* Revision 1.6 2001/11/07 04:01:59 steve
* eval_const uses scope instead of a string path.
*
* Revision 1.5 2001/07/25 03:10:48 steve
* Create a config.h.in file to hold all the config
* junk, and support gcc 3.0. (Stephan Boettcher)
*
* Revision 1.4 2001/01/20 02:15:50 steve
* apologize for not supporting non-constant delays.
*
* Revision 1.3 2001/01/14 23:04:55 steve
* Generalize the evaluation of floating point delays, and
* get it working with delay assignment statements.
*
* Allow parameters to be referenced by hierarchical name.
*
* Revision 1.2 2000/02/23 02:56:53 steve
* Macintosh compilers do not support ident.
*
* Revision 1.1 1999/09/04 19:11:46 steve
* Add support for delayed non-blocking assignments.
*
*/
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