OpenSTA/sdc/CycleAccting.cc

432 lines
14 KiB
C++

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2025, Parallax Software, Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//
// The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software.
//
// Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
//
// This notice may not be removed or altered from any source distribution.
#include "CycleAccting.hh"
#include <cmath> // ceil
#include <algorithm> // max
#include "Debug.hh"
#include "Fuzzy.hh"
#include "Units.hh"
#include "TimingRole.hh"
#include "Clock.hh"
#include "Sdc.hh"
namespace sta {
CycleAcctings::CycleAcctings(Sdc *sdc) :
sdc_(sdc)
{
}
CycleAcctings::~CycleAcctings()
{
clear();
}
void
CycleAcctings::clear()
{
cycle_acctings_.deleteContentsClear();
}
// Determine cycle accounting "on demand".
CycleAccting *
CycleAcctings::cycleAccting(const ClockEdge *src,
const ClockEdge *tgt)
{
if (src == nullptr)
src = tgt;
CycleAccting probe(src, tgt);
CycleAccting *acct = cycle_acctings_.findKey(&probe);
if (acct == nullptr) {
acct = new CycleAccting(src, tgt);
if (src == sdc_->defaultArrivalClockEdge())
acct->findDefaultArrivalSrcDelays();
else
acct->findDelays(sdc_);
cycle_acctings_.insert(acct);
}
return acct;
}
void
CycleAcctings::reportClkToClkMaxCycleWarnings(Report *report)
{
// Find cycle acctings that exceed max cycle count. Eliminate
// duplicate warnings between different src/tgt clk edges.
ClockPairSet clk_warnings;
for (Clock *src_clk : *sdc_->clocks()) {
for (const RiseFall *src_rf : RiseFall::range()) {
ClockEdge *src = src_clk->edge(src_rf);
for (Clock *tgt_clk : *sdc_->clocks()) {
for (const RiseFall *tgt_rf : RiseFall::range()) {
ClockEdge *tgt = tgt_clk->edge(tgt_rf);
CycleAccting probe(src, tgt);
CycleAccting *acct = cycle_acctings_.findKey(&probe);
if (acct && acct->maxCyclesExceeded()) {
// Canonicalize the warning wrt src/tgt.
ClockPair clk_pair1(src_clk, tgt_clk);
ClockPair clk_pair2(tgt_clk, src_clk);
if (!clk_warnings.hasKey(clk_pair1)
&& !clk_warnings.hasKey(clk_pair2)) {
report->warn(1010, "No common period was found between clocks %s and %s.",
src_clk->name(),
tgt_clk->name());
clk_warnings.insert(clk_pair1);
}
}
}
}
}
}
}
////////////////////////////////////////////////////////////////
CycleAccting::CycleAccting(const ClockEdge *src,
const ClockEdge *tgt) :
src_(src),
tgt_(tgt),
max_cycles_exceeded_(false)
{
for (int i = 0; i <= TimingRole::index_max; i++) {
delay_[i] = MinMax::min()->initValue();
required_[i] = 0;
src_cycle_[i] = 0;
tgt_cycle_[i] = 0;
}
}
void
CycleAccting::findDelays(StaState *sta)
{
Debug *debug = sta->debug();
const Unit *time_unit = sta->units()->timeUnit();
debugPrint(debug, "cycle_acct", 1, "%s -> %s",
src_->name(),
tgt_->name());
const int setup_index = TimingRole::setup()->index();
const int latch_setup_index = TimingRole::latchSetup()->index();
const int data_check_setup_index = TimingRole::dataCheckSetup()->index();
const int hold_index = TimingRole::hold()->index();
const int gclk_hold_index = TimingRole::gatedClockHold()->index();
Clock *src_clk = src_->clock();
Clock *tgt_clk = tgt_->clock();
double tgt_opp_time1 = tgt_->opposite()->time();
double tgt_period = tgt_clk->period();
double src_period = src_clk->period();
if (tgt_period > 0.0 && src_period > 0.0) {
// If the clocks are related (ie, generated clock and its source) allow
// allow enough cycles to match up the common period.
int tgt_max_cycle;
if (tgt_period > src_period)
tgt_max_cycle = 100;
else {
int ratio = std::ceil(src_period / tgt_period);
tgt_max_cycle = std::max(ratio, 1000);
}
bool tgt_past_src = false;
bool src_past_tgt = false;
int tgt_cycle = firstCycle(tgt_);
int src_cycle = 0;
while (tgt_cycle <= tgt_max_cycle) {
double tgt_cycle_start = tgt_cycle * tgt_period;
double tgt_time = tgt_cycle_start + tgt_->time();
double tgt_opp_time = tgt_cycle_start + tgt_opp_time1;
for (src_cycle = firstCycle(src_);
;
src_cycle++) {
double src_cycle_start = src_cycle * src_period;
double src_time = src_cycle_start + src_->time();
// Make sure both setup and hold required are determined.
if (tgt_past_src && src_past_tgt
// Synchronicity achieved.
&& fuzzyEqual(src_cycle_start, tgt_cycle_start)) {
debugPrint(debug, "cycle_acct", 1, " setup = %s, required = %s",
time_unit->asString(delay_[setup_index]),
time_unit->asString(required_[setup_index]));
debugPrint(debug, "cycle_acct", 1, " hold = %s, required = %s",
time_unit->asString(delay_[hold_index]),
time_unit->asString(required_[hold_index]));
debugPrint(debug, "cycle_acct", 1,
" converged at src cycles = %d tgt cycles = %d",
src_cycle, tgt_cycle);
return;
}
if (fuzzyGreater(src_cycle_start, tgt_cycle_start + tgt_period)
&& src_past_tgt)
break;
debugPrint(debug, "cycle_acct", 2, " %s src cycle %d %s + %s = %s",
src_->name(),
src_cycle,
time_unit->asString(src_cycle_start),
time_unit->asString(src_->time()),
time_unit->asString(src_time));
debugPrint(debug, "cycle_acct", 2, " %s tgt cycle %d %s + %s = %s",
tgt_->name(),
tgt_cycle,
time_unit->asString(tgt_cycle_start),
time_unit->asString(tgt_->time()),
time_unit->asString(tgt_time));
// For setup checks, target has to be AFTER source.
if (fuzzyGreater(tgt_time, src_time)) {
tgt_past_src = true;
double delay = tgt_time - src_time;
if (fuzzyLess(delay, delay_[setup_index])) {
double required = tgt_time - src_cycle_start;
setSetupAccting(src_cycle, tgt_cycle, delay, required);
debugPrint(debug, "cycle_acct", 2,
" setup min delay = %s, required = %s",
time_unit->asString(delay_[setup_index]),
time_unit->asString(required_[setup_index]));
}
}
// Data check setup checks are zero cycle.
if (fuzzyLessEqual(tgt_time, src_time)) {
double setup_delay = src_time - tgt_time;
if (fuzzyLess(setup_delay, delay_[data_check_setup_index])) {
double setup_required = tgt_time - src_cycle_start;
setAccting(TimingRole::dataCheckSetup(), src_cycle, tgt_cycle,
setup_delay, setup_required);
double hold_required = tgt_time - (src_cycle_start + src_period);
double hold_delay = (src_period + src_time) - tgt_time;
setAccting(TimingRole::dataCheckHold(),
src_cycle + 1, tgt_cycle, hold_delay, hold_required);
}
}
// Latch setup cycle accting for the enable is the data clk edge
// closest to the disable (opposite) edge.
if (fuzzyGreater(tgt_opp_time, src_time)) {
double delay = tgt_opp_time - src_time;
if (fuzzyLess(delay, delay_[latch_setup_index])) {
double latch_tgt_time = tgt_time;
int latch_tgt_cycle = tgt_cycle;
// Enable time is the edge before the disable.
if (tgt_time > tgt_opp_time) {
latch_tgt_time -= tgt_period;
latch_tgt_cycle--;
}
double required = latch_tgt_time - src_cycle_start;
setAccting(TimingRole::latchSetup(),
src_cycle, latch_tgt_cycle, delay, required);
debugPrint(debug, "cycle_acct", 2,
" latch setup min delay = %s, required = %s",
time_unit->asString(delay_[latch_setup_index]),
time_unit->asString(required_[latch_setup_index]));
}
}
// For hold checks, target has to be BEFORE source.
if (fuzzyLessEqual(tgt_time, src_time)) {
double delay = src_time - tgt_time;
src_past_tgt = true;
if (fuzzyLess(delay, delay_[hold_index])) {
double required = tgt_time - src_cycle_start;
setHoldAccting(src_cycle, tgt_cycle, delay, required);
debugPrint(debug, "cycle_acct", 2,
" hold min delay = %s, required = %s",
time_unit->asString(delay_[hold_index]),
time_unit->asString(required_[hold_index]));
}
}
// Gated clock hold checks are in the same cycle as the
// setup check.
if (fuzzyLessEqual(tgt_opp_time, src_time)) {
double delay = src_time - tgt_time;
if (fuzzyLess(delay, delay_[gclk_hold_index])) {
double required = tgt_time - src_cycle_start;
setAccting(TimingRole::gatedClockHold(),
src_cycle, tgt_cycle, delay, required);
debugPrint(debug, "cycle_acct", 2,
" gated clk hold min delay = %s, required = %s",
time_unit->asString(delay_[gclk_hold_index]),
time_unit->asString(required_[gclk_hold_index]));
}
}
}
tgt_cycle++;
}
max_cycles_exceeded_ = true;
debugPrint(debug, "cycle_acct", 1,
" max cycles exceeded after %d src cycles, %d tgt_cycles",
src_cycle, tgt_cycle);
}
else if (tgt_period > 0.0)
findDefaultArrivalSrcDelays();
}
int
CycleAccting::firstCycle(const ClockEdge *clk_edge) const
{
if (clk_edge->time() < 0)
return 1;
else if (clk_edge->time() < clk_edge->clock()->period())
return 0;
else
return -1;
}
void
CycleAccting::setSetupAccting(int src_cycle,
int tgt_cycle,
float delay,
float req)
{
setAccting(TimingRole::setup(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::outputSetup(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::gatedClockSetup(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::recovery(), src_cycle, tgt_cycle, delay, req);
}
void
CycleAccting::setHoldAccting(int src_cycle,
int tgt_cycle,
float delay,
float req)
{
setAccting(TimingRole::hold(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::outputHold(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::removal(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::latchHold(), src_cycle, tgt_cycle, delay, req);
}
void
CycleAccting::setAccting(const TimingRole *role,
int src_cycle,
int tgt_cycle,
float delay,
float req)
{
int index = role->index();
src_cycle_[index] = src_cycle;
tgt_cycle_[index] = tgt_cycle;
delay_[index] = delay;
required_[index] = req;
}
void
CycleAccting::findDefaultArrivalSrcDelays()
{
const Clock *tgt_clk = tgt_->clock();
float tgt_time = tgt_->time();
float tgt_period = tgt_clk->period();
// Unclocked arrival setup check is in cycle zero.
if (tgt_time > tgt_period)
setDefaultSetupAccting(0, 0, tgt_time - tgt_period, tgt_time - tgt_period);
else if (tgt_time > 0.0)
setDefaultSetupAccting(0, 0, tgt_time, tgt_time);
else
setDefaultSetupAccting(0, 1, tgt_period, tgt_period);
setDefaultHoldAccting(0, 0, 0.0, tgt_time);
}
void
CycleAccting::setDefaultSetupAccting(int src_cycle,
int tgt_cycle,
float delay,
float req)
{
setSetupAccting(src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::latchSetup(), src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::dataCheckSetup(), src_cycle, tgt_cycle, delay, req);
}
void
CycleAccting::setDefaultHoldAccting(int src_cycle,
int tgt_cycle,
float delay,
float req)
{
setHoldAccting(src_cycle, tgt_cycle, delay, req);
setAccting(TimingRole::dataCheckHold(), src_cycle, tgt_cycle, delay, req);
}
float
CycleAccting::requiredTime(const TimingRole *check_role)
{
return required_[check_role->index()];
}
float
CycleAccting::sourceTimeOffset(const TimingRole *check_role)
{
return sourceCycle(check_role) * src_->clock()->period();
}
int
CycleAccting::sourceCycle(const TimingRole *check_role)
{
return src_cycle_[check_role->index()];
}
int
CycleAccting::targetCycle(const TimingRole *check_role)
{
return tgt_cycle_[check_role->index()];
}
float
CycleAccting::targetTimeOffset(const TimingRole *check_role)
{
return targetCycle(check_role) * tgt_->clock()->period();
}
////////////////////////////////////////////////////////////////
bool
CycleAcctingLess::operator()(const CycleAccting *acct1,
const CycleAccting *acct2) const
{
int src_index1 = acct1->src()->index();
int src_index2 = acct2->src()->index();
return src_index1 < src_index2
|| (src_index1 == src_index2
&& acct1->target()->index() < acct2->target()->index());
}
size_t
CycleAcctingHash::operator()(const CycleAccting *acct) const
{
return hashSum(acct->src()->index(), acct->target()->index());
}
bool
CycleAcctingEqual::operator()(const CycleAccting *acct1,
const CycleAccting *acct2) const
{
return acct1->src() == acct2->src()
&& acct1->target() == acct2->target();
}
} // namespace