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liberty: refactor out constant bools

This commit is contained in:
Emil J. Tywoniak 2026-07-28 16:39:08 +02:00
parent 82914a0204
commit ef69127001
1 changed files with 12 additions and 59 deletions
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71
frontends/liberty/liberty.cc
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@ -210,7 +210,6 @@ static void create_ff(RTLIL::Module *module, const LibertyAst *node)
{ {
auto [iq_sig, iqn_sig] = find_latch_ff_wires(module, node); auto [iq_sig, iqn_sig] = find_latch_ff_wires(module, node);
RTLIL::SigSpec clk_sig, data_sig, clear_sig, preset_sig; RTLIL::SigSpec clk_sig, data_sig, clear_sig, preset_sig;
bool clk_polarity = true, clear_polarity = true, preset_polarity = true;
const std::string name = module->name.unescape(); const std::string name = module->name.unescape();
std::optional<char> clear_preset_var1; std::optional<char> clear_preset_var1;
@ -250,21 +249,21 @@ static void create_ff(RTLIL::Module *module, const LibertyAst *node)
cell->setPort(ID::C, clk_sig); cell->setPort(ID::C, clk_sig);
if (clear_sig.size() == 0 && preset_sig.size() == 0) { if (clear_sig.size() == 0 && preset_sig.size() == 0) {
cell->type = stringf("$_DFF_%c_", clk_polarity ? 'P' : 'N'); cell->type = stringf("$_DFF_P_");
} }
if (clear_sig.size() == 1 && preset_sig.size() == 0) { if (clear_sig.size() == 1 && preset_sig.size() == 0) {
cell->type = stringf("$_DFF_%c%c0_", clk_polarity ? 'P' : 'N', clear_polarity ? 'P' : 'N'); cell->type = stringf("$_DFF_PP0_");
cell->setPort(ID::R, clear_sig); cell->setPort(ID::R, clear_sig);
} }
if (clear_sig.size() == 0 && preset_sig.size() == 1) { if (clear_sig.size() == 0 && preset_sig.size() == 1) {
cell->type = stringf("$_DFF_%c%c1_", clk_polarity ? 'P' : 'N', preset_polarity ? 'P' : 'N'); cell->type = stringf("$_DFF_PP1_");
cell->setPort(ID::R, preset_sig); cell->setPort(ID::R, preset_sig);
} }
if (clear_sig.size() == 1 && preset_sig.size() == 1) { if (clear_sig.size() == 1 && preset_sig.size() == 1) {
cell->type = stringf("$_DFFSR_%c%c%c_", clk_polarity ? 'P' : 'N', preset_polarity ? 'P' : 'N', clear_polarity ? 'P' : 'N'); cell->type = stringf("$_DFFSR_PPP_");
SigBit s_sig = preset_sig; SigBit s_sig = preset_sig;
SigBit r_sig = clear_sig; SigBit r_sig = clear_sig;
@ -301,7 +300,6 @@ static bool create_latch(RTLIL::Module *module, const LibertyAst *node, bool fla
{ {
auto [iq_sig, iqn_sig] = find_latch_ff_wires(module, node); auto [iq_sig, iqn_sig] = find_latch_ff_wires(module, node);
RTLIL::SigSpec enable_sig, data_sig, clear_sig, preset_sig; RTLIL::SigSpec enable_sig, data_sig, clear_sig, preset_sig;
bool enable_polarity = true, clear_polarity = true, preset_polarity = true;
for (auto child : node->children) { for (auto child : node->children) {
if (child->id == "enable") if (child->id == "enable")
@ -327,63 +325,18 @@ static bool create_latch(RTLIL::Module *module, const LibertyAst *node, bool fla
cell->setPort(ID::A, iq_sig); cell->setPort(ID::A, iq_sig);
cell->setPort(ID::Y, iqn_sig); cell->setPort(ID::Y, iqn_sig);
if (clear_sig.size() == 1) if (clear_sig.size() == 1) {
{ RTLIL::SigSpec clear_negative = module->NotGate(NEW_ID, clear_sig);
RTLIL::SigSpec clear_negative = clear_sig; data_sig = module->AndGate(NEW_ID, data_sig, clear_negative);
RTLIL::SigSpec clear_enable = clear_sig; enable_sig = module->OrGate(NEW_ID, enable_sig, clear_sig);
if (clear_polarity == true || clear_polarity != enable_polarity)
{
RTLIL::Cell *inv = module->addCell(NEW_ID, ID($_NOT_));
inv->setPort(ID::A, clear_sig);
inv->setPort(ID::Y, module->addWire(NEW_ID));
if (clear_polarity == true)
clear_negative = inv->getPort(ID::Y);
if (clear_polarity != enable_polarity)
clear_enable = inv->getPort(ID::Y);
}
RTLIL::Cell *data_gate = module->addCell(NEW_ID, ID($_AND_));
data_gate->setPort(ID::A, data_sig);
data_gate->setPort(ID::B, clear_negative);
data_gate->setPort(ID::Y, data_sig = module->addWire(NEW_ID));
RTLIL::Cell *enable_gate = module->addCell(NEW_ID, enable_polarity ? ID($_OR_) : ID($_AND_));
enable_gate->setPort(ID::A, enable_sig);
enable_gate->setPort(ID::B, clear_enable);
enable_gate->setPort(ID::Y, enable_sig = module->addWire(NEW_ID));
} }
if (preset_sig.size() == 1) if (preset_sig.size() == 1) {
{ data_sig = module->OrGate(NEW_ID, data_sig, preset_sig);
RTLIL::SigSpec preset_positive = preset_sig; enable_sig = module->OrGate(NEW_ID, enable_sig, preset_sig);
RTLIL::SigSpec preset_enable = preset_sig;
if (preset_polarity == false || preset_polarity != enable_polarity)
{
RTLIL::Cell *inv = module->addCell(NEW_ID, ID($_NOT_));
inv->setPort(ID::A, preset_sig);
inv->setPort(ID::Y, module->addWire(NEW_ID));
if (preset_polarity == false)
preset_positive = inv->getPort(ID::Y);
if (preset_polarity != enable_polarity)
preset_enable = inv->getPort(ID::Y);
}
RTLIL::Cell *data_gate = module->addCell(NEW_ID, ID($_OR_));
data_gate->setPort(ID::A, data_sig);
data_gate->setPort(ID::B, preset_positive);
data_gate->setPort(ID::Y, data_sig = module->addWire(NEW_ID));
RTLIL::Cell *enable_gate = module->addCell(NEW_ID, enable_polarity ? ID($_OR_) : ID($_AND_));
enable_gate->setPort(ID::A, enable_sig);
enable_gate->setPort(ID::B, preset_enable);
enable_gate->setPort(ID::Y, enable_sig = module->addWire(NEW_ID));
} }
cell = module->addCell(NEW_ID, stringf("$_DLATCH_%c_", enable_polarity ? 'P' : 'N')); cell = module->addCell(NEW_ID, stringf("$_DLATCH_P_"));
cell->setPort(ID::D, data_sig); cell->setPort(ID::D, data_sig);
cell->setPort(ID::Q, iq_sig); cell->setPort(ID::Q, iq_sig);
cell->setPort(ID::E, enable_sig); cell->setPort(ID::E, enable_sig);