1use ark_ff::{
 2    biginteger::BigInteger256 as BigInteger,
 3    fields::{FftParameters, Fp256, Fp256Parameters, FpParameters},
 4};
 5
 6pub type Fr = Fp256<FrParameters>;
 7
 8pub struct FrParameters;
 9
10impl Fp256Parameters for FrParameters {}
11impl FftParameters for FrParameters {
12    type BigInt = BigInteger;
13
14    const TWO_ADICITY: u32 = 32;
15
16    #[rustfmt::skip]
17    const TWO_ADIC_ROOT_OF_UNITY: BigInteger = BigInteger([
18        0xb9b58d8c5f0e466a,
19        0x5b1b4c801819d7ec,
20        0xaf53ae352a31e64,
21        0x5bf3adda19e9b27b,
22    ]);
23}
24impl FpParameters for FrParameters {
25    /// MODULUS = 52435875175126190479447740508185965837690552500527637822603658699938581184513
26    #[rustfmt::skip]
27    const MODULUS: BigInteger = BigInteger([
28        0xffffffff00000001,
29        0x53bda402fffe5bfe,
30        0x3339d80809a1d805,
31        0x73eda753299d7d48,
32    ]);
33
34    const MODULUS_BITS: u32 = 255;
35
36    const CAPACITY: u32 = Self::MODULUS_BITS - 1;
37
38    const REPR_SHAVE_BITS: u32 = 1;
39
40    #[rustfmt::skip]
41    const R: BigInteger = BigInteger([
42        0x1fffffffe,
43        0x5884b7fa00034802,
44        0x998c4fefecbc4ff5,
45        0x1824b159acc5056f,
46    ]);
47
48    #[rustfmt::skip]
49    const R2: BigInteger = BigInteger([
50        0xc999e990f3f29c6d,
51        0x2b6cedcb87925c23,
52        0x5d314967254398f,
53        0x748d9d99f59ff11,
54    ]);
55
56    const INV: u64 = 0xfffffffeffffffff;
57
58    //
59    #[rustfmt::skip]
60    const GENERATOR: BigInteger = BigInteger([
61        0xefffffff1,
62        0x17e363d300189c0f,
63        0xff9c57876f8457b0,
64        0x351332208fc5a8c4,
65    ]);
66
67    #[rustfmt::skip]
68    const MODULUS_MINUS_ONE_DIV_TWO: BigInteger = BigInteger([
69        0x7fffffff80000000,
70        0xa9ded2017fff2dff,
71        0x199cec0404d0ec02,
72        0x39f6d3a994cebea4,
73    ]);
74
75    // T and T_MINUS_ONE_DIV_TWO, where MODULUS - 1 = 2^S * T
76
77    // T = (MODULUS - 1) / 2^S =
78    // 12208678567578594777604504606729831043093128246378069236549469339647
79    #[rustfmt::skip]
80    const T: BigInteger = BigInteger([
81        0xfffe5bfeffffffff,
82        0x9a1d80553bda402,
83        0x299d7d483339d808,
84        0x73eda753,
85    ]);
86
87    // (T - 1) / 2 =
88    // 6104339283789297388802252303364915521546564123189034618274734669823
89    #[rustfmt::skip]
90    const T_MINUS_ONE_DIV_TWO: BigInteger = BigInteger([
91        0x7fff2dff7fffffff,
92        0x4d0ec02a9ded201,
93        0x94cebea4199cec04,
94        0x39f6d3a9,
95    ]);
96}