OpenSTA/include/sta/TimingModel.hh

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2026, 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.

#pragma once

#include <string>
#include <string_view>

#include "Delay.hh"
#include "LibertyClass.hh"
#include "Variables.hh"

namespace sta {

// Abstract base class for GateTimingModel and CheckTimingModel.
class TimingModel
{
public:
  TimingModel(LibertyCell *cell);
  virtual ~TimingModel() = default;
  virtual void setIsScaled(bool is_scaled) = 0;

protected:
  LibertyCell *cell_;
};

// Abstract base class for LinearModel and TableModel.
class GateTimingModel : public TimingModel
{
public:
  GateTimingModel(LibertyCell *cell);
  // Gate delay calculation.
  virtual void gateDelay(const Pvt *pvt,
                         float in_slew,
                         float load_cap,
                         // Return values.
                         float &gate_delay,
                         float &drvr_slew) const = 0;
  // Fill in pocv parameters in gate_delay, drvr_slew.
  virtual void gateDelayPocv(const Pvt *pvt,
                             float in_slew,
                             float load_cap,
                             const MinMax *min_max,
                             PocvMode pocv_mode,
                             // Return values.
                             ArcDelay &gate_delay,
                             Slew &drvr_slew) const = 0;
  virtual std::string reportGateDelay(const Pvt *pvt,
                                      float in_slew,
                                      float load_cap,
                                      const MinMax *min_max,
                                      PocvMode pocv_mode,
                                      int digits) const = 0;
  virtual float driveResistance(const Pvt *pvt) const = 0;
};

// Abstract base class for timing check timing models.
class CheckTimingModel : public TimingModel
{
public:
  CheckTimingModel(LibertyCell *cell);
  // Timing check margin delay calculation.
  virtual ArcDelay checkDelay(const Pvt *pvt,
                              float from_slew,
                              float to_slew,
                              float related_out_cap,
                              const MinMax *min_max,
                              PocvMode pocv_mode) const = 0;
  virtual std::string reportCheckDelay(const Pvt *pvt,
                                       float from_slew,
                                       std::string_view from_slew_annotation,
                                       float to_slew,
                                       float related_out_cap,
                                       const MinMax *min_max,
                                       PocvMode pocv_mode,
                                       int digits) const = 0;
};

} // namespace sta