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abc9_ops: -prep_dff_map to cope with plain $_DFF_[NP]_ flops

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This commit is contained in:
Eddie Hung 2020-04-13 17:30:29 -07:00
parent c10757a8ea
commit a1ae5845f8
1 changed files with 39 additions and 12 deletions
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51
passes/techmap/abc9_ops.cc
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@ -134,13 +134,22 @@ void prep_dff_hier(RTLIL::Design *design)
for (auto module : design->selected_modules())
for (auto cell : module->cells()) {
auto inst_module = design->module(cell->type);
if (inst_module && inst_module->get_bool_attribute(ID::abc9_flop)) {
modules_sel.select(inst_module);
if (inst_module && inst_module->attributes.count(ID::abc9_flop)) {
if (inst_module->get_blackbox_attribute(true /* ignore_wb */))
log_error("Module '%s' with (* abc9_flop *) is not a whitebox.\n", log_id(inst_module));
// Derive modules for all instantiations of (* abc9_flop *)
auto derived_type = inst_module->derive(design, cell->parameters);
auto derived_module = design->module(derived_type);
if (!derived_module->get_bool_attribute(ID::abc9_flop))
continue;
// And remember one representative cell (for its parameters)
if (modules_sel.selected_modules.insert(derived_type).second)
if (!modules_sel.selected_whole_module(derived_type)) {
if (derived_type != cell->type)
modules_sel.select(inst_module);
modules_sel.select(derived_module);
cells_sel.select(module, cell);
}
}
}
}
@ -150,19 +159,20 @@ void prep_dff_map(RTLIL::Design *design)
for (auto module : design->modules()) {
vector<Cell*> specify_cells;
SigBit D, Q;
Cell* dff_cell = nullptr;
for (auto cell : module->cells())
if (cell->type.in(ID($_DFF_N_), ID($_DFF_P_))) {
if (D != SigBit())
if (dff_cell)
log_error("More than one $_DFF_[NP]_ cell found in module '%s' marked (* abc9_flop *)\n", log_id(module));
D = cell->getPort(ID::D);
Q = cell->getPort(ID::Q);
dff_cell = cell;
// Block sequential synthesis on cells with (* init = 1 *)
// Block sequential synthesis on cells with (* init *) != 1'b0
// because ABC9 doesn't support them
Q = cell->getPort(ID::Q);
log_assert(GetSize(Q.wire) == 1);
Const init = Q.wire->attributes.at(ID::init, State::Sx);
log_assert(GetSize(init) == 1);
if (init == State::S1) {
if (init != State::S0) {
log_warning("Module '%s' contains a %s cell with non-zero initial state -- this is not unsupported for ABC9 sequential synthesis. Treating as a blackbox.\n", log_id(module), log_id(cell->type));
module->makeblackbox();
@ -176,9 +186,26 @@ void prep_dff_map(RTLIL::Design *design)
}
else if (cell->type.in(ID($specify2), ID($specify3), ID($specrule)))
specify_cells.emplace_back(cell);
if (D == SigBit())
if (!dff_cell)
log_error("$_DFF_[NP]_ cell not found in module '%s' marked (* abc9_flop *)\n", log_id(module));
D = dff_cell->getPort(ID::D);
// Add a dummy enable mux feeding DFF.D to ensure that:
// (i) a driving cell exists, so that 'submod' will have
// an output port
// (ii) DFF.Q will exist in this submodule
{
auto c = module->addCell(NEW_ID, ID($_MUX_));
auto w = module->addWire(NEW_ID);
c->setPort(ID::A, D);
c->setPort(ID::B, Q);
c->setPort(ID::S, State::S0);
c->setPort(ID::Y, w);
dff_cell->setPort(ID::D, w);
D = w;
}
// Rewrite $specify cells that end with $_DFF_[NP]_.Q
// to $_DFF_[NP]_.D since it will be moved into
// the submodule
@ -253,7 +280,7 @@ void prep_xaiger(RTLIL::Module *module, bool dff)
continue;
auto inst_module = design->module(cell->type);
bool abc9_flop = inst_module && inst_module->get_bool_attribute(ID::abc9_flop);
bool abc9_flop = inst_module && inst_module->attributes.count(ID::abc9_flop);
if (abc9_flop && !dff)
continue;
@ -339,7 +366,7 @@ void prep_xaiger(RTLIL::Module *module, bool dff)
log_assert(cell);
RTLIL::Module* box_module = design->module(cell->type);
if (!box_module || (!box_module->get_bool_attribute(ID::abc9_box) && !box_module->get_bool_attribute(ID::abc9_flop)))
if (!box_module || !box_module->get_bool_attribute(ID::abc9_box))
continue;
cell->attributes[ID::abc9_box_seq] = box_count++;
@ -967,7 +994,7 @@ void reintegrate(RTLIL::Module *module, bool dff_mode)
SigSpec outputs = std::move(jt->second);
mapped_cell->connections_.erase(jt);
auto abc9_flop = box_module->attributes.count(ID::abc9_flop);
auto abc9_flop = box_module->get_bool_attribute(ID::abc9_flop);
if (!abc9_flop) {
for (const auto &i : inputs)
bit_users[i].insert(mapped_cell->name);