1use ark_ff::{biginteger::BigInteger256 as BigInteger, fields::*};
  2
  3pub type Fr = Fp256<FrParameters>;
  4
  5pub struct FrParameters;
  6
  7impl Fp256Parameters for FrParameters {}
  8impl FftParameters for FrParameters {
  9    type BigInt = BigInteger;
 10
 11    const TWO_ADICITY: u32 = 28;
 12
 13    #[rustfmt::skip]
 14    const TWO_ADIC_ROOT_OF_UNITY: BigInteger = BigInteger([
 15        7164790868263648668u64,
 16        11685701338293206998u64,
 17        6216421865291908056u64,
 18        1756667274303109607u64,
 19    ]);
 20}
 21impl FpParameters for FrParameters {
 22    /// MODULUS = 21888242871839275222246405745257275088548364400416034343698204186575808495617
 23    #[rustfmt::skip]
 24    const MODULUS: BigInteger = BigInteger([
 25        4891460686036598785u64,
 26        2896914383306846353u64,
 27        13281191951274694749u64,
 28        3486998266802970665u64,
 29    ]);
 30
 31    const MODULUS_BITS: u32 = 254;
 32
 33    const CAPACITY: u32 = Self::MODULUS_BITS - 1;
 34
 35    const REPR_SHAVE_BITS: u32 = 2;
 36
 37    /// R = pow(2, 256) % MODULUS
 38    ///   = 6350874878119819312338956282401532410528162663560392320966563075034087161851
 39    #[rustfmt::skip]
 40    const R: BigInteger = BigInteger([
 41        12436184717236109307u64,
 42        3962172157175319849u64,
 43        7381016538464732718u64,
 44        1011752739694698287u64,
 45    ]);
 46
 47    /// R2 = R * R % MODULUS
 48    ///    = 944936681149208446651664254269745548490766851729442924617792859073125903783
 49    #[rustfmt::skip]
 50    const R2: BigInteger = BigInteger([
 51        1997599621687373223u64,
 52        6052339484930628067u64,
 53        10108755138030829701u64,
 54        150537098327114917u64,
 55    ]);
 56
 57    /// INV = (-MODULUS) ^ {-1} % pow(2, 64) = 14042775128853446655
 58    const INV: u64 = 14042775128853446655u64;
 59
 60    /// GENERATOR = 5
 61    #[rustfmt::skip]
 62    const GENERATOR: BigInteger = BigInteger([
 63        1949230679015292902u64,
 64        16913946402569752895u64,
 65        5177146667339417225u64,
 66        1571765431670520771u64,
 67    ]);
 68
 69    /// (MODULUS - 1)/2 =
 70    /// 10944121435919637611123202872628637544274182200208017171849102093287904247808
 71    #[rustfmt::skip]
 72    const MODULUS_MINUS_ONE_DIV_TWO: BigInteger = BigInteger([
 73        0xa1f0fac9f8000000,
 74        0x9419f4243cdcb848,
 75        0xdc2822db40c0ac2e,
 76        0x183227397098d014,
 77    ]);
 78
 79    // T and T_MINUS_ONE_DIV_TWO, where r - 1 = 2^s * t
 80
 81    /// T = (MODULUS - 1) / 2^s =
 82    /// 81540058820840996586704275553141814055101440848469862132140264610111
 83    #[rustfmt::skip]
 84    const T: BigInteger = BigInteger([
 85        0x9b9709143e1f593f,
 86        0x181585d2833e8487,
 87        0x131a029b85045b68,
 88        0x30644e72e,
 89    ]);
 90
 91    /// (T - 1) / 2 =
 92    /// 40770029410420498293352137776570907027550720424234931066070132305055
 93    #[rustfmt::skip]
 94    const T_MINUS_ONE_DIV_TWO: BigInteger = BigInteger([
 95        0xcdcb848a1f0fac9f,
 96        0x0c0ac2e9419f4243,
 97        0x098d014dc2822db4,
 98        0x183227397,
 99    ]);
100}