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

273 lines (239 sloc) 6.676 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
*/
# include "config.h"
# include <cstring>
# include <iostream>
# include "PExpr.h"
# include "netlist.h"
# include "netmisc.h"
# include "compiler.h"
verinum* PExpr::eval_const(Design*, NetScope*) const
{
return 0;
}
verinum* PEBinary::eval_const(Design*des, 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()) {
res = new verinum(*l + *r);
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '-': {
if (l->is_defined() && r->is_defined()) {
res = new verinum(*l - *r);
} else {
res = new verinum(verinum::Vx, l->len());
}
break;
}
case '*': {
if (l->is_defined() && r->is_defined()) {
res = new verinum(*l * *r);
} 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;
}
verinum* PEConcat::eval_const(Design*des, NetScope*scope) const
{
verinum*accum = parms_[0]->eval_const(des, scope);
if (accum == 0)
return 0;
for (unsigned idx = 1 ; idx < parms_.count() ; idx += 1) {
verinum*tmp = parms_[idx]->eval_const(des, scope);
if (tmp == 0) {
delete accum;
return 0;
}
assert(tmp);
*accum = concat(*accum, *tmp);
delete tmp;
}
return accum;
}
/*
* Evaluate an identifier as a constant expression. This is only
* possible if the identifier is that of a parameter.
*/
verinum* PEIdent::eval_const(Design*des, NetScope*scope) const
{
assert(scope);
NetNet*net;
NetEvent*eve;
const NetExpr*expr;
const name_component_t&name_tail = path_.back();
// Handle the special case that this ident is a genvar
// variable name. In that case, the genvar meaning preempts
// everything and we just return that value immediately.
if (scope->genvar_tmp
&& strcmp(name_tail.name,scope->genvar_tmp) == 0) {
return new verinum(scope->genvar_tmp_val);
}
symbol_search(des, scope, path_, net, expr, eve);
if (expr == 0)
return 0;
const NetEConst*eval = dynamic_cast<const NetEConst*>(expr);
if (eval == 0) {
cerr << get_fileline() << ": internal error: Unable to evaluate "
<< "constant expression (parameter=" << path_
<< "): " << *expr << endl;
return 0;
}
assert(eval);
if (!name_tail.index.empty())
return 0;
return new verinum(eval->value());
}
verinum* PEFNumber::eval_const(Design*, NetScope*) const
{
long val = value_->as_long();
return new verinum(val);
}
verinum* PENumber::eval_const(Design*, NetScope*) const
{
return new verinum(value());
}
verinum* PEString::eval_const(Design*, NetScope*) const
{
return new verinum(string(text_));
}
verinum* PETernary::eval_const(Design*des, 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(Design*des, 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 ((uint64_t)0, 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;
}
Jump to Line
Something went wrong with that request. Please try again.