Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

281 lines (252 sloc) 7.432 kb
/*
* Copyright (c) 1998-1999 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: eval.cc,v 1.30 2002/08/12 01:34:59 steve Exp $"
#endif
# include "config.h"
# include <iostream>
# include "PExpr.h"
# include "netlist.h"
# include "compiler.h"
verinum* PExpr::eval_const(const Design*, const NetScope*) const
{
return 0;
}
verinum* PEBinary::eval_const(const Design*des, const NetScope*scope) const
{
verinum*l = left_->eval_const(des, scope);
if (l == 0) return 0;
verinum*r = right_->eval_const(des, scope);
if (r == 0) {
delete l;
return 0;
}
verinum*res;
switch (op_) {
case '+': {
if (l->is_defined() && r->is_defined()) {
long lv = l->as_long();
long rv = r->as_long();
res = new verinum(lv+rv, l->len());
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '-': {
if (l->is_defined() && r->is_defined()) {
long lv = l->as_long();
long rv = r->as_long();
res = new verinum(lv-rv, l->len());
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '*': {
if (l->is_defined() && r->is_defined()) {
long lv = l->as_long();
long rv = r->as_long();
res = new verinum(lv * rv, l->len());
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '/': {
if (l->is_defined() && r->is_defined()) {
long lv = l->as_long();
long rv = r->as_long();
res = new verinum(lv / rv, l->len());
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '%': {
if (l->is_defined() && r->is_defined()) {
long lv = l->as_long();
long rv = r->as_long();
res = new verinum(lv % rv, l->len());
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case 'l': { // left shift (<<)
assert(r->is_defined());
unsigned long rv = r->as_ulong();
res = new verinum(verinum::V0, l->len());
if (rv < res->len()) {
unsigned cnt = res->len() - rv;
for (unsigned idx = 0 ; idx < cnt ; idx += 1)
res->set(idx+rv, l->get(idx));
}
break;
}
case 'r': { // right shift (>>)
assert(r->is_defined());
unsigned long rv = r->as_ulong();
res = new verinum(verinum::V0, l->len());
if (rv < res->len()) {
unsigned cnt = res->len() - rv;
for (unsigned idx = 0 ; idx < cnt ; idx += 1)
res->set(idx, l->get(idx+rv));
}
break;
}
default:
delete l;
delete r;
return 0;
}
delete l;
delete r;
return res;
}
/*
* Evaluate an identifier as a constant expression. This is only
* possible if the identifier is that of a parameter.
*/
verinum* PEIdent::eval_const(const Design*des, const NetScope*scope) const
{
assert(scope);
const NetExpr*expr = des->find_parameter(scope, path_);
if (expr == 0)
return 0;
const NetEConst*eval = dynamic_cast<const NetEConst*>(expr);
assert(eval);
if (msb_ || lsb_)
return 0;
return new verinum(eval->value());
}
verinum* PEFNumber::eval_const(const Design*, const NetScope*) const
{
long val = value_->as_long();
return new verinum(val);
}
verinum* PENumber::eval_const(const Design*, const NetScope*) const
{
return new verinum(value());
}
verinum* PEString::eval_const(const Design*, const NetScope*) const
{
return new verinum(string(text_));
}
verinum* PETernary::eval_const(const Design*des, const NetScope*scope) const
{
verinum*test = expr_->eval_const(des, scope);
if (test == 0)
return 0;
verinum::V bit = test->get(0);
delete test;
switch (bit) {
case verinum::V0:
return fal_->eval_const(des, scope);
case verinum::V1:
return tru_->eval_const(des, scope);
default:
return 0;
// XXXX It is possible to handle this case if both fal_
// and tru_ are constant. Someday...
}
}
verinum* PEUnary::eval_const(const Design*des, const NetScope*scope) const
{
verinum*val = expr_->eval_const(des, scope);
if (val == 0)
return 0;
switch (op_) {
case '+':
return val;
case '-': {
/* We need to expand the value a bit if we are
taking the 2's complement so that we are
guaranteed to not overflow. */
verinum tmp (0UL, val->len()+1);
for (unsigned idx = 0 ; idx < val->len() ; idx += 1)
tmp.set(idx, val->get(idx));
*val = v_not(tmp) + verinum(verinum::V1, 1);
val->has_sign(true);
return val;
}
}
delete val;
return 0;
}
/*
* $Log: eval.cc,v $
* Revision 1.30 2002/08/12 01:34:59 steve
* conditional ident string using autoconfig.
*
* Revision 1.29 2002/06/07 02:57:54 steve
* Simply give up on constants with indices.
*
* Revision 1.28 2002/06/06 18:57:04 steve
* Better error for identifier index eval.
*
* Revision 1.27 2002/05/23 03:08:51 steve
* Add language support for Verilog-2001 attribute
* syntax. Hook this support into existing $attribute
* handling, and add number and void value types.
*
* Add to the ivl_target API new functions for access
* of complex attributes attached to gates.
*
* Revision 1.26 2001/12/29 22:10:10 steve
* constant eval of arithmetic with x and z.
*
* Revision 1.25 2001/12/29 00:43:55 steve
* Evaluate constant right shifts.
*
* Revision 1.24 2001/12/03 04:47:15 steve
* Parser and pform use hierarchical names as hname_t
* objects instead of encoded strings.
*
* Revision 1.23 2001/11/07 04:01:59 steve
* eval_const uses scope instead of a string path.
*
* Revision 1.22 2001/11/06 06:11:55 steve
* Support more real arithmetic in delay constants.
*
* Revision 1.21 2001/07/25 03:10:49 steve
* Create a config.h.in file to hold all the config
* junk, and support gcc 3.0. (Stephan Boettcher)
*
* Revision 1.20 2001/02/09 02:49:59 steve
* Be more clear about scope of failure.
*
* Revision 1.19 2001/01/27 05:41:48 steve
* Fix sign extension of evaluated constants. (PR#91)
*
* Revision 1.18 2001/01/14 23:04:56 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 1.17 2001/01/04 04:47:51 steve
* Add support for << is signal indices.
*
* Revision 1.16 2000/12/10 22:01:36 steve
* Support decimal constants in behavioral delays.
*
* Revision 1.15 2000/09/07 22:38:13 steve
* Support unary + and - in constants.
*/
Jump to Line
Something went wrong with that request. Please try again.