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Remove old timing code

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This commit is contained in:
Eddie Hung 2018-08-06 16:09:17 -07:00
parent 06584f2e74
commit f3e46df709
1 changed files with 0 additions and 88 deletions
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88
common/timing.cc
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@ -37,7 +37,6 @@ struct Timing
bool net_delays;
bool update;
delay_t min_slack;
PortRefVector current_path;
PortRefVector *crit_path;
DelayFrequency *slack_histogram;
@ -56,96 +55,10 @@ struct Timing
{
}
delay_t follow_net(NetInfo *net, int path_length, delay_t slack)
{
const delay_t default_budget = slack / (path_length + 1);
delay_t net_budget = default_budget;
for (auto &usr : net->users) {
auto delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
if (crit_path)
current_path.push_back(&usr);
// If budget override exists, use that value and do not increment path_length
auto budget = default_budget;
if (ctx->getBudgetOverride(net, usr, budget)) {
if (update)
usr.budget = std::min(usr.budget, budget);
budget = follow_user_port(usr, path_length, slack - budget);
net_budget = std::min(net_budget, budget);
}
else {
budget = follow_user_port(usr, path_length + 1, slack - delay);
net_budget = std::min(net_budget, budget);
if (update)
usr.budget = std::min(usr.budget, delay + budget);
}
if (crit_path)
current_path.pop_back();
}
return net_budget;
}
// Follow a path, returning budget to annotate
delay_t follow_user_port(PortRef &user, int path_length, delay_t slack)
{
delay_t value;
if (ctx->getPortClock(user.cell, user.port) != IdString()) {
// At the end of a timing path (arguably, should check setup time
// here too)
value = slack / path_length;
if (slack < min_slack) {
min_slack = slack;
if (crit_path)
*crit_path = current_path;
}
if (slack_histogram) {
int slack_ps = ctx->getDelayNS(slack) * 1000;
(*slack_histogram)[slack_ps]++;
}
} else {
// Default to the path ending here, if no further paths found
value = slack / path_length;
// Follow outputs of the user
for (auto port : user.cell->ports) {
if (port.second.type == PORT_OUT) {
DelayInfo comb_delay;
// Look up delay through this path
bool is_path = ctx->getCellDelay(user.cell, user.port, port.first, comb_delay);
if (is_path) {
NetInfo *net = port.second.net;
if (net) {
delay_t path_budget = follow_net(net, path_length, slack - comb_delay.maxDelay());
value = std::min(value, path_budget);
}
}
}
}
}
return value;
}
delay_t walk_paths()
{
const auto clk_period = delay_t(1.0e12 / ctx->target_freq);
#if 0
// Go through all clocked drivers and distribute the available path
// slack evenly into the budget of every sink on the path
for (auto &cell : ctx->cells) {
for (auto port : cell.second->ports) {
if (port.second.type == PORT_OUT) {
IdString clock_domain = ctx->getPortClock(cell.second.get(), port.first);
if (clock_domain != IdString()) {
delay_t slack = clk_period; // TODO: clock constraints
DelayInfo clkToQ;
if (ctx->getCellDelay(cell.second.get(), clock_domain, port.first, clkToQ))
slack -= clkToQ.maxDelay();
if (port.second.net)
follow_net(port.second.net, 0, slack);
}
}
}
}
#else
// First, compute the topographical order of nets to walk through
// the circuit, assuming it is a _acyclic_ graph
// TODO: Handle the case where it is cyclic, e.g. combinatorial loops
@ -384,7 +297,6 @@ struct Timing
}
std::reverse(crit_path->begin(), crit_path->end());
}
#endif
return min_slack;
}