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Refactor new code and existing code

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This commit is contained in:
Eddie Hung 2018-07-24 09:20:07 -07:00
parent adc1a86648
commit 7b4c5594ed
1 changed files with 25 additions and 61 deletions
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86
common/timing.cc
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@ -26,10 +26,12 @@
NEXTPNR_NAMESPACE_BEGIN
static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack);
typedef std::unordered_map<const PortInfo*, delay_t> UpdateMap;
static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, UpdateMap &updates);
// Follow a path, returning budget to annotate
static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, delay_t slack)
static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, delay_t slack, UpdateMap &updates)
{
delay_t value;
if (ctx->getPortClock(user.cell, user.port) != IdString()) {
@ -48,7 +50,7 @@ static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, de
if (is_path) {
NetInfo *net = port.second.net;
if (net) {
delay_t path_budget = follow_net(ctx, net, path_length, slack - comb_delay);
delay_t path_budget = follow_net(ctx, net, path_length, slack - comb_delay, updates);
value = std::min(value, path_budget);
}
}
@ -56,23 +58,26 @@ static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, de
}
}
if (value < user.budget) {
user.budget = value;
auto ret = updates.emplace(&user.cell->ports.at(user.port), value);
if (!ret.second && value < ret.first->second) {
ret.first->second = value;
}
return value;
}
static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack)
static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, UpdateMap &updates)
{
delay_t net_budget = slack / (path_length + 1);
for (auto &usr : net->users) {
net_budget = std::min(net_budget, follow_user_port(ctx, usr, path_length + 1, slack));
net_budget = std::min(net_budget, follow_user_port(ctx, usr, path_length + 1, slack, updates));
}
return net_budget;
}
void assign_budget(Context *ctx)
{
UpdateMap updates;
log_break();
log_info("Annotating ports with timing budgets\n");
// Clear delays to a very high value first
@ -90,15 +95,23 @@ void assign_budget(Context *ctx)
if (clock_domain != IdString()) {
delay_t slack = delay_t(1.0e12 / ctx->target_freq); // TODO: clock constraints
if (port.second.net)
follow_net(ctx, port.second.net, 0, slack);
follow_net(ctx, port.second.net, 0, slack, updates);
}
}
}
}
// Post-allocation check
// Update the budgets
for (auto &net : ctx->nets) {
for (auto user : net.second->users) {
for (size_t i = 0; i < net.second->users.size(); ++i) {
auto& user = net.second->users[i];
auto pi = &user.cell->ports.at(user.port);
auto it = updates.find(pi);
if (it == updates.end()) continue;
auto budget = ctx->getNetinfoRouteDelay(net.second.get(), i) + it->second;
user.budget = ctx->getBudgetOverride(net.second->driver, budget);
// Post-update check
if (user.budget < 0)
log_warning("port %s.%s, connected to net '%s', has negative "
"timing budget of %fns\n",
@ -115,58 +128,9 @@ void assign_budget(Context *ctx)
log_info("Checksum: 0x%08x\n", ctx->checksum());
}
typedef std::unordered_map<const PortInfo*, delay_t> updates_t;
static delay_t follow_net_update(Context *ctx, NetInfo *net, int path_length, delay_t slack, updates_t& updates);
// Follow a path, returning budget to annotate
static delay_t follow_user_port_update(Context *ctx, PortRef &user, int path_length, delay_t slack, updates_t& updates)
{
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;
} 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) {
delay_t 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_update(ctx, net, path_length, slack - comb_delay, updates);
value = std::min(value, path_budget);
}
}
}
}
}
auto ret = updates.emplace(&user.cell->ports.at(user.port), value);
if (!ret.second && value < ret.first->second) {
ret.first->second = value;
}
return value;
}
static delay_t follow_net_update(Context *ctx, NetInfo *net, int path_length, delay_t slack, updates_t& updates)
{
delay_t net_budget = slack / (path_length + 1);
for (size_t i = 0; i < net->users.size(); ++i) {
auto& usr = net->users[i];
net_budget = std::min(net_budget, follow_user_port_update(ctx, usr, path_length + 1, slack - ctx->getNetinfoRouteDelay(net, i), updates));
}
return net_budget;
}
void update_budget(Context *ctx)
{
updates_t updates;
UpdateMap updates;
// Go through all clocked drivers and distribute the available path slack evenly into every budget
for (auto &cell : ctx->cells) {
@ -175,7 +139,7 @@ void update_budget(Context *ctx)
IdString clock_domain = ctx->getPortClock(cell.second.get(), port.first);
if (clock_domain != IdString()) {
if (port.second.net)
follow_net_update(ctx, port.second.net, 0, delay_t(1.0e12 / ctx->target_freq), updates);
follow_net(ctx, port.second.net, 0, delay_t(1.0e12 / ctx->target_freq), updates);
}
}
}