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Agressively merge NetAssign_ within concatenations.

This commit is contained in:
steve 2000-09-10 03:59:59 +00:00
parent 8a69c54886
commit 3c94635f99
1 changed files with 46 additions and 15 deletions
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61
elab_lval.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/ */
#if !defined(WINNT) && !defined(macintosh) #if !defined(WINNT) && !defined(macintosh)
#ident "$Id: elab_lval.cc,v 1.2 2000/09/10 02:18:16 steve Exp $" #ident "$Id: elab_lval.cc,v 1.3 2000/09/10 03:59:59 steve Exp $"
#endif #endif
# include "PExpr.h" # include "PExpr.h"
@ -79,28 +79,56 @@ NetAssign_* PExpr::elaborate_lval(Design*des, NetScope*scope) const
/* /*
* Concatenation expressions can appear as l-values. Handle them here. * Concatenation expressions can appear as l-values. Handle them here.
*
* If adjacent l-values in the concatenation are not bit selects, then
* merge them into a single NetAssign_ object. This can happen is code
* like ``{ ...a, b, ...}''. As long as "a" and "b" do not have bit
* selects (or the bit selects are constant) we can merge the
* NetAssign_ objects.
*
* Be careful to get the bit order right. In the expression ``{a, b}''
* a is the MSB and b the LSB. Connect the LSB to the low pins of the
* NetAssign_ object.
*/ */
NetAssign_* PEConcat::elaborate_lval(Design*des, NetScope*scope) const NetAssign_* PEConcat::elaborate_lval(Design*des, NetScope*scope) const
{ {
#if 0
NetNet*ll = elaborate_net(des, scope->name(), 0, 0, 0, 0,
Link::STRONG, Link::STRONG);
if (ll != 0) {
NetAssign_*lv = new NetAssign_(scope->local_symbol(),
ll->pin_count());
for (unsigned idx = 0 ; idx < ll->pin_count() ; idx += 1)
connect(lv->pin(idx), ll->pin(idx));
des->add_node(lv);
return lv;
}
#endif
NetAssign_*res = 0; NetAssign_*res = 0;
for (unsigned idx = 0 ; idx < parms_.count() ; idx += 1) { for (unsigned idx = 0 ; idx < parms_.count() ; idx += 1) {
NetAssign_*tmp = parms_[idx]->elaborate_lval(des, scope); NetAssign_*tmp = parms_[idx]->elaborate_lval(des, scope);
assert(tmp); assert(tmp);
tmp->more = res; /* If adjacent l-values in the concatenation are not bit
res = tmp; selects, then merge them into a single NetAssign_
object.
If we cannot merge, then just link the new one to the
previous one. */
if (res && (res->bmux() == 0) && (tmp->bmux() == 0)) {
unsigned wid1 = tmp->pin_count();
unsigned wid2 = res->pin_count() + tmp->pin_count();
NetAssign_*tmp2 = new NetAssign_(res->name(), wid2);
tmp2->more = res->more;
res->more = 0;
for (unsigned idx = 0 ; idx < wid1 ; idx += 1)
connect(tmp2->pin(idx), tmp->pin(idx));
for (unsigned idx = 0 ; idx < res->pin_count() ; idx += 1)
connect(tmp2->pin(idx+wid1), res->pin(idx));
delete res;
delete tmp;
res = tmp2;
des->add_node(res);
} else {
tmp->more = res;
res = tmp;
}
} }
return res; return res;
@ -234,6 +262,9 @@ NetAssign_* PEIdent::elaborate_lval(Design*des, NetScope*scope) const
/* /*
* $Log: elab_lval.cc,v $ * $Log: elab_lval.cc,v $
* Revision 1.3 2000/09/10 03:59:59 steve
* Agressively merge NetAssign_ within concatenations.
*
* Revision 1.2 2000/09/10 02:18:16 steve * Revision 1.2 2000/09/10 02:18:16 steve
* elaborate complex l-values * elaborate complex l-values
* *