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Handle special case of FF with enable and constant data.

This commit is contained in:
steve 2003-10-27 02:18:04 +00:00
parent 65ae69843b
commit a503e2d91f
1 changed files with 15 additions and 3 deletions
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18
synth2.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: synth2.cc,v 1.31 2003/08/28 04:11:19 steve Exp $"
#ident "$Id: synth2.cc,v 1.32 2003/10/27 02:18:04 steve Exp $"
#endif
# include "config.h"
@ -539,6 +539,8 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
NetNet*asig = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, nex_map->pin_count());
asig->local_flag(true);
assert(if_ != 0);
bool flag = if_->synth_async(des, scope, nex_map, asig);
assert(asig->pin_count() == ff->width());
@ -567,6 +569,7 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
delete expr_input;
assert(events_in.count() == 1);
assert(else_ != 0);
return else_->synth_sync(des, scope, ff, nex_map,
nex_out, svector<NetEvProbe*>(0))
&& flag;
@ -578,10 +581,15 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
is not asyncronous because we know the condition is not
included in the sensitivity list, but if the if_ case is
constant (has no inputs) then we can model this as a
synchronous set/reset. */
synchronous set/reset.
This is only synchronous set/reset if there is a true and a
false clause, and no inputs. The "no inputs" requirement is
met if the assignments are of all constant values. */
assert(if_ != 0);
NexusSet*a_set = if_->nex_input();
if (a_set->count() == 0) {
if ((a_set->count() == 0) && if_ && else_) {
NetNet*rst = expr_->synthesize(des);
assert(rst->pin_count() == 1);
@ -617,6 +625,7 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
delete a_set;
assert(else_ != 0);
return else_->synth_sync(des, scope, ff, nex_map,
nex_out, svector<NetEvProbe*>(0))
&& flag;
@ -877,6 +886,9 @@ void synth2(Design*des)
/*
* $Log: synth2.cc,v $
* Revision 1.32 2003/10/27 02:18:04 steve
* Handle special case of FF with enable and constant data.
*
* Revision 1.31 2003/08/28 04:11:19 steve
* Spelling patch.
*