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bug fixes

This commit is contained in:
Stan Lee 2026-05-11 16:01:39 -07:00
parent 1b89bc7675
commit 1be9a8985d
1 changed files with 58 additions and 33 deletions
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91
passes/techmap/clockgate.cc
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@ -187,30 +187,33 @@ static std::pair<std::optional<ClockGateCell>, std::optional<ClockGateCell>>
return std::make_pair(pos, neg);
}
static double return_default_activity(IdString attr) {
static double get_cell_activity(Cell *cell, IdString pin, IdString attr) {
const char *name = pin.c_str();
if (name[0] == '\\') name++; // remove any backslash prefix
std::string prefix = std::string(name) + "="; // prefix for pin (A=0.5)
// Full string attribute value from the cell.
std::string attribute = cell->get_string_attribute(attr);
std::istringstream iss(attribute);
for (std::string tok; iss >> tok; )
if (tok.compare(0, prefix.size(), prefix) == 0)
return atof(tok.c_str() + prefix.size());
// Unable to find any corresponding value, return default
return (attr == ID($DUTY)) ? 1.0 : 0.0;
}
// Returns the activity/duty of a bit for a given signal.
static double get_bit_activity(SigMap &sigmap, SigBit bit, IdString attr) {
SigBit sigbit = sigmap(bit);
// Special case for constants
if (bit == State::S1) return return_default_activity(attr);
if (bit == State::S0) return 0.0;
// Special case for undefined wires
if (!sigbit.wire) return return_default_activity(attr);
// Get the activity/duty from the wire's string attribute
std::istringstream iss(sigbit.wire->get_string_attribute(attr));
std::string tok;
for (int i = 0; i <= sigbit.offset; i++) {
if (i == sigbit.offset) return atof(tok.c_str()); // found activity/duty for the bit
static void update_ff_activity_attr(Cell *cell, IdString attr_key, double new_clk_value) {
std::string out;
std::istringstream iss(cell->get_string_attribute(attr_key));
for (std::string tok; iss >> tok; ) {
if (tok.compare(0, 3, "EN=") == 0) continue; // remove EN from attribute
if (tok.compare(0, 4, "CLK=") == 0)
out += stringf("CLK=%f ", new_clk_value); // Update CLK value
else
out += tok + " "; // All other values remain unchanged
}
// Case that activity/duty not found
return return_default_activity(attr);
cell->set_string_attribute(attr_key, out);
}
struct ClockgatePass : public Pass {
@ -293,6 +296,12 @@ struct ClockgatePass : public Pass {
int src_count = 0;
// Total sum of disabled FFs on a clock net
double en_disabled_sum = 0;
// Used to set activity/duty attributes of the gated clock net
bool activity_set = false;
double gclk_duty = 0.0;
double gclk_ackt = 0.0;
// FF on the clock net used to read activity/duty attributes
Cell* representative_ff = nullptr;
};
ClkNetInfo clk_info_from_ff(FfData& ff) {
@ -411,10 +420,12 @@ struct ClockgatePass : public Pass {
// Gated clock info
auto &gclk_info = clk_nets[info];
gclk_info.net_size++;
if (!gclk_info.representative_ff)
gclk_info.representative_ff = cell;
if (use_disabled_threshold) {
// Calculate the duty cycle of the enable signal.
double ce_duty = get_bit_activity(sigmap, info.ce_bit, ID($DUTY));
double ce_duty = get_cell_activity(cell, ID(EN), ID($DUTY));
double ce_active_frac = info.pol_ce ? ce_duty : (1.0 - ce_duty);
// Fraction of time this FF is disabled (CE not asserted).
@ -453,23 +464,30 @@ struct ClockgatePass : public Pass {
// If disabled threshold is used, calculate the activity/duty of the gated clock.
if (use_disabled_threshold) {
double clk_duty = get_bit_activity(sigmap, clk.clk_bit, ID($DUTY));
double ce_duty = get_bit_activity(sigmap, clk.ce_bit, ID($DUTY));
double clk_activity = get_bit_activity(sigmap, clk.clk_bit, ID($ACKT));
double ce_activity = get_bit_activity(sigmap, clk.ce_bit, ID($ACKT));
Cell* rep = gclk.representative_ff;
double clk_duty = get_cell_activity(rep, ID(CLK), ID($DUTY));
double ce_duty = get_cell_activity(rep, ID(EN), ID($DUTY));
double clk_activity = get_cell_activity(rep, ID(CLK), ID($ACKT));
double ce_activity = get_cell_activity(rep, ID(EN), ID($ACKT));
double ce_active_frac = clk.pol_ce ? ce_duty : (1.0 - ce_duty);
// Calculate the duty and activity of the gated clock.
double gclk_duty = clk_duty * ce_duty;
double gclk_duty = clk_duty * ce_active_frac;
double gclk_ackt = clk_activity * ce_activity;
// Set new activity/duty attributes
gclk.new_net->set_string_attribute(ID($DUTY),
stringf("%f", gclk_duty));
gclk.new_net->set_string_attribute(ID($ACKT),
stringf("%f", gclk_ackt));
// Set fanout to 1 for the ICG
// Set cell attributes for the new ICG
icg->set_string_attribute(ID($FANOUT), "1");
icg->set_string_attribute(ID($ACKT),
stringf("CLK=%f EN=%f SE=0.0 GCLK=%f",
clk_activity, ce_activity, gclk_ackt));
icg->set_string_attribute(ID($DUTY),
stringf("CLK=%f EN=%f SE=0.0 GCLK=%f",
clk_duty, ce_duty, gclk_duty));
// Set for use in FF annotation
gclk.gclk_duty = gclk_duty;
gclk.gclk_ackt = gclk_ackt;
gclk.activity_set = true;
}
gclk.icg_cell = icg;
@ -530,6 +548,13 @@ struct ClockgatePass : public Pass {
Cell *new_ff = ff.emit();
new_ff->set_bool_attribute(ID::is_clock_gated);
// Update the flop with new activity/duty attributes
if (it->second.activity_set) {
auto &g = it->second;
update_ff_activity_attr(new_ff, ID($DUTY), g.gclk_duty);
update_ff_activity_attr(new_ff, ID($ACKT), g.gclk_ackt);
}
gated_flop_count++;
}
ce_ffs.clear();