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Evaluate constant bit select of constants.

This commit is contained in:
steve 2002-04-25 05:04:31 +00:00
parent 74eb544962
commit c7107dc973
1 changed files with 47 additions and 4 deletions
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51
elab_expr.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: elab_expr.cc,v 1.54 2002/04/14 21:16:48 steve Exp $"
#ident "$Id: elab_expr.cc,v 1.55 2002/04/25 05:04:31 steve Exp $"
#endif
# include "config.h"
@ -411,9 +411,49 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
select attached to it. Generate a NetESelect
object to select the bit as desired. */
NetExpr*mtmp = msb_->elaborate_expr(des, scope);
NetESelect*stmp = new NetESelect(tmp, mtmp, 1);
tmp->set_line(*this);
tmp = stmp;
if (! dynamic_cast<NetEConst*>(mtmp)) {
NetExpr*re = mtmp->eval_tree();
if (re) {
delete mtmp;
mtmp = re;
}
}
/* Let's first try to get constant values for both
the parameter and the bit select. If they are
both constant, then evaluate the bit select and
return instead a single-bit constant. */
NetEConst*le = dynamic_cast<NetEConst*>(tmp);
NetEConst*re = dynamic_cast<NetEConst*>(mtmp);
if (le && re) {
verinum lv = le->value();
verinum rv = re->value();
verinum::V rb = verinum::Vx;
long ridx = rv.as_long();
if ((ridx >= 0) && (ridx < lv.len())) {
rb = lv[ridx];
} else if ((ridx >= 0) && (!lv.has_len())) {
if (lv.has_sign())
rb = lv[lv.len()-1];
else
rb = verinum::V0;
}
NetEConst*re = new NetEConst(verinum(rb, 1));
delete tmp;
delete mtmp;
tmp = re;
} else {
NetESelect*stmp = new NetESelect(tmp, mtmp, 1);
tmp->set_line(*this);
tmp = stmp;
}
}
@ -745,6 +785,9 @@ NetExpr* PEUnary::elaborate_expr(Design*des, NetScope*scope, bool) const
/*
* $Log: elab_expr.cc,v $
* Revision 1.55 2002/04/25 05:04:31 steve
* Evaluate constant bit select of constants.
*
* Revision 1.54 2002/04/14 21:16:48 steve
* Evaluate logical not at elaboration time.
*