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Enable latch generation in synthesis. 

(reworked patch supplied by Johann Klammer)
This commit is contained in:
Martin Whitaker 2016-03-11 23:29:38 +00:00
parent 81d3b7a25c
commit 0e537c5465
1 changed files with 32 additions and 16 deletions
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48
synth2.cc
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@ -1581,28 +1581,44 @@ bool NetProcTop::synth_async(Design*des)
bool flag = statement_->synth_async(des, scope(), nex_set, nex_out, enables, bitmasks);
if (!flag) return false;
bool latch_flag = false;
for (unsigned idx = 0 ; idx < enables.pin_count() ; idx += 1) {
if (!enables.pin(idx).is_linked(scope()->tie_hi())) {
flag = tie_off_floating_inputs_(des, nex_set, nex_in, bitmasks, false);
if (!flag) return false;
for (unsigned idx = 0 ; idx < nex_set.size() ; idx += 1) {
if (enables.pin(idx).is_linked(scope()->tie_hi())) {
connect(nex_set[idx].lnk, nex_out.pin(idx));
} else {
cerr << get_fileline() << ": warning: "
<< "A latch has been inferred for '"
<< nex_set[idx].lnk.nexus()->pick_any_net()->name()
<< "'." << endl;
latch_flag = true;
if (debug_synth2) {
cerr << get_fileline() << ": debug: "
<< "Top level making a "
<< nex_set[idx].wid << "-wide "
<< "NetLatch device." << endl;
}
NetLatch*latch = new NetLatch(scope(), scope()->local_symbol(),
nex_set[idx].wid);
des->add_node(latch);
latch->set_line(*this);
NetNet*tmp = nex_out.pin(idx).nexus()->pick_any_net();
tmp->set_line(*this);
assert(tmp);
tmp = crop_to_width(des, tmp, latch->width());
connect(nex_set[idx].lnk, latch->pin_Q());
connect(tmp->pin(0), latch->pin_Data());
assert (enables.pin(idx).is_linked());
connect(enables.pin(idx), latch->pin_Enable());
}
}
if (latch_flag) {
cerr << get_fileline() << ": sorry: Latches are not "
<< "currently supported in synthesis." << endl;
des->errors += 1;
return false;
}
flag = tie_off_floating_inputs_(des, nex_set, nex_in, bitmasks, false);
if (!flag) return false;
for (unsigned idx = 0 ; idx < nex_set.size() ; idx += 1)
connect(nex_set[idx].lnk, nex_out.pin(idx));
synthesized_design_ = des;
return true;