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Timing fixes

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-11-14 08:46:10 +00:00
parent 9f13bc7eb0
commit adc50a207f
2 changed files with 15 additions and 1 deletions
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1
common/nextpnr.cc
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@ -409,6 +409,7 @@ void Context::check() const
void BaseCtx::addClock(IdString net, float freq)
{
log_info(" constraining clock net '%s' to %.02f MHz\n", net.c_str(this), freq);
std::unique_ptr<ClockConstraint> cc(new ClockConstraint());
cc->period = getCtx()->getDelayFromNS(1000 / freq);
cc->high = getCtx()->getDelayFromNS(500 / freq);

15
common/timing.cc
View File

@ -313,7 +313,6 @@ struct Timing
auto process_endpoint = [&](IdString clksig, ClockEdge edge, delay_t setup) {
const auto net_arrival = nd.max_arrival;
const auto endpoint_arrival = net_arrival + net_delay + setup;
auto path_budget = clk_period - endpoint_arrival;
delay_t period;
// Set default period
if (edge == startdomain.first.edge) {
@ -335,6 +334,8 @@ struct Timing
}
}
}
auto path_budget = period - endpoint_arrival;
if (update) {
auto budget_share = budget_override ? 0 : path_budget / net_length_plus_one;
usr.budget = std::min(usr.budget, net_delay + budget_share);
@ -532,13 +533,21 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_fmax, bool p
std::map<IdString, std::pair<ClockPair, CriticalPath>> clock_reports;
std::map<IdString, double> clock_fmax;
std::vector<ClockPair> xclock_paths;
std::set<IdString> empty_clocks; // set of clocks with no interior paths
if (print_path || print_fmax) {
for (auto path : crit_paths) {
const ClockEvent &a = path.first.start;
const ClockEvent &b = path.first.end;
empty_clocks.insert(a.clock);
empty_clocks.insert(b.clock);
}
for (auto path : crit_paths) {
const ClockEvent &a = path.first.start;
const ClockEvent &b = path.first.end;
if (a.clock != b.clock || a.clock == ctx->id("$async$"))
continue;
double Fmax;
empty_clocks.erase(a.clock);
if (a.edge == b.edge)
Fmax = 1000 / ctx->getDelayNS(path.second.path_delay);
else
@ -659,6 +668,10 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_fmax, bool p
log_info("Max frequency for clock '%s': %.02f MHz\n", clock.first.c_str(ctx), clock_fmax[clock.first]);
}
}
for (auto &eclock : empty_clocks) {
if (eclock != ctx->id("$async$"))
log_info("Clock '%s' has no interior paths\n", eclock.c_str(ctx));
}
log_break();
int start_field_width = 0, end_field_width = 0;