pasta_curves/
fields.rs

1//! This module contains implementations for the two finite fields of the Pallas
2//! and Vesta curves.
3
4mod fp;
5mod fq;
6
7pub use fp::*;
8pub use fq::*;
9
10/// Converts 64-bit little-endian limbs to 32-bit little endian limbs.
11#[cfg(feature = "gpu")]
12fn u64_to_u32(limbs: &[u64]) -> alloc::vec::Vec<u32> {
13    limbs
14        .iter()
15        .flat_map(|limb| [(limb & 0xFFFF_FFFF) as u32, (limb >> 32) as u32].into_iter())
16        .collect()
17}
18
19#[cfg(feature = "gpu")]
20#[test]
21fn test_u64_to_u32() {
22    use rand::{RngCore, SeedableRng};
23    use rand_xorshift::XorShiftRng;
24
25    let mut rng = XorShiftRng::from_seed([0; 16]);
26    let u64_limbs: alloc::vec::Vec<u64> = (0..6).map(|_| rng.next_u64()).collect();
27    let u32_limbs = crate::fields::u64_to_u32(&u64_limbs);
28
29    let u64_le_bytes: alloc::vec::Vec<u8> = u64_limbs
30        .iter()
31        .flat_map(|limb| limb.to_le_bytes())
32        .collect();
33    let u32_le_bytes: alloc::vec::Vec<u8> = u32_limbs
34        .iter()
35        .flat_map(|limb| limb.to_le_bytes())
36        .collect();
37
38    assert_eq!(u64_le_bytes, u32_le_bytes);
39}