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Improved method for finding fsm_expand candidates

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This commit is contained in:
Clifford Wolf 2013-03-25 02:24:11 +01:00
parent 4a7d624bef
commit 0f5378b559
1 changed files with 7 additions and 5 deletions
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12
passes/fsm/fsm_expand.cc
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@ -43,7 +43,8 @@ struct FsmExpand
bool is_cell_merge_candidate(RTLIL::Cell *cell)
{
if (cell->type == "$mux" || cell->type == "$pmux" || cell->type == "$safe_pmux")
return cell->connections.at("\\A").width < 2;
if (cell->connections.at("\\A").width < 2)
return true;
RTLIL::SigSpec new_signals;
if (cell->connections.count("\\A") > 0)
@ -52,16 +53,18 @@ struct FsmExpand
new_signals.append(assign_map(cell->connections["\\B"]));
if (cell->connections.count("\\S") > 0)
new_signals.append(assign_map(cell->connections["\\S"]));
if (cell->connections.count("\\Y") > 0)
new_signals.append(assign_map(cell->connections["\\Y"]));
new_signals.sort_and_unify();
new_signals.remove_const();
if (new_signals.width > 4)
return false;
new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_IN"]));
new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_OUT"]));
if (new_signals.width > 3)
return false;
if (cell->connections.count("\\Y") > 0) {
new_signals.append(assign_map(cell->connections["\\Y"]));
new_signals.sort_and_unify();
@ -140,7 +143,6 @@ struct FsmExpand
input_sig.sort_and_unify();
input_sig.remove_const();
assert(input_sig.width <= 4 || cell->type == "$mux" || cell->type == "$pmux" || cell->type == "$safe_pmux");
std::vector<RTLIL::Const> truth_tab;
for (int i = 0; i < (1 << input_sig.width); i++) {