#ifndef ATOMS_SKY130_CARRY1_H_

#define ATOMS_SKY130_CARRY1_H_

#include <string>

#include <vector>

#include "../circuit.h"

#include "../geometry/instance.h"

#include "../geometry/point.h"

#include "../layout.h"

#include "../memory_bank.h"

#include "../routing/routing_grid.h"

#include "../cell.h"

#include "proto/parameters/sky130_carry1.pb.h"

#include "atom.h"

#include "sky130_parameters.h"

namespace bfg {

class DesignDatabase;

namespace routing {

class RouteManager;

} // namespace routing

namespace atoms {

// Sky130Carry1 forms 1 bit of the carry chain:

//

//

// +-----+

// P --------+----| XOR |---- S

// +---|----| |

// C_I ----+ | +-----+

// | |

// +-------+ +---------|---|--------------- CONFIG_OUT

// CONFIG_IN -| FF | | | |

// | |---+ | |\

// CONFIG_CLK -|> | | +--| |-------------- C_O

// +-------+ | +------| |

// | | |/ 2:1 MUX

// |\ |

// G_0 -| |----+ (i_0)

// G_1 -| |

// |/ 2:1 MUX

//

// Inputs:

// C_I, carry in, typically from a prior Sky130Carry1 bit

// P, propagate, typically from a LUT

// G_0, generate, typically from another LUT

// G_1, generate, typically from a bypass input

// CONFIG_IN, scan-chain config in

// CONFIG_CLK, scan-chain clock

//

// Outputs:

// S, the sum output

// C_O, carry out

// CONFIG_OUT, scan-chain config out

//

class Sky130Carry1 : public Atom {

public:

struct Parameters : public Sky130Parameters {

bool reverse_order = false;

void ToProto(proto::parameters::Sky130Carry1 *pb) const;

void FromProto(const proto::parameters::Sky130Carry1 &pb);

};

Sky130Carry1(

const Parameters &parameters, DesignDatabase *design_db)

: Atom(design_db),

parameters_(parameters) {

}

geometry::Instance *AddConfigMemory(RowGuide *row) const;

geometry::Instance *AddGenerateSelectMux(RowGuide *row) const;

geometry::Instance *AddSumXor(RowGuide *row) const;

geometry::Instance *AddCarrySelectMux(RowGuide *row) const;

Cell *Generate() override;

private:

void GenerateCircuit(const std::vector<geometry::Instance*> &taps,

geometry::Instance *config_memory,

geometry::Instance *generate_select,

geometry::Instance *carry_select,

geometry::Instance *sum_xor,

bfg::Circuit *circuit) const;

Parameters parameters_;

};

} // namespace atoms

} // namespace bfg

#endif // ATOMS_SKY130_CARRY1_H_