TEMPLATE adder {
  CELL <cellname> {
    CELLTYPE = block ;
    ATTRIBUTE { adder }
    PIN [<msb_in>:0] a_in {
      DIRECTION = input ;
    }
    PIN [<msb_in>:0] b_in {
      DIRECTION = input ;
    }
    PIN c_in {
      DIRECTION = input ;
    }
    PIN [<msb_out>:0] out {
      DIRECTION = output ;
    }
    FUNCTION {
      BEHAVIOR {
        out = a_in + b_in + c_in ;
      }
    }
    GROUP carry_bits { 0 : <msb_out> }
    VECTOR ( 01 c_in -> 01 out[carry_bits] ) {
      ENERGY = 1 ;
    }
    VECTOR ( 10 c_in -> 10 out[carry_bits] ) {
      ENERGY = 1 ;
    }
    VECTOR ( 10 c_in -> 01 out[carry_bits] ) {
      ENERGY = 1 ;
    }
    VECTOR ( 01 c_in -> 10 out[carry_bits] ) {
      ENERGY = 1 ;
    }
    TEMPLATE carry_propagate {
      GROUP low_bits { 0 : <high_bit> }
      VECTOR ( 01 a_in[low_bits] -> 01 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 10 a_in[low_bits] -> 10 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 10 a_in[low_bits] -> 01 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 01 a_in[low_bits] -> 10 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 01 b_in[low_bits] -> 01 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 10 b_in[low_bits] -> 10 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 10 b_in[low_bits] -> 01 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
      VECTOR ( 01 b_in[low_bits] -> 10 out[<high_bit>] ) {
        ENERGY = 1 ;
      }
    }
    GROUP high_bits { 0 : <msb_in> }
    carry_propagate {
      high_bit = high_bits ;
    }
  }
}
adder {
  cellname = adder_8 ;
  msb_in = 7 ;
  msb_out = 8 ;
}