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Add impl Mul<(u32, u32, u32, u32)> for FieldElement51x4.

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Henry de Valence 2018-11-12 11:58:59 -08:00
parent 70199d6094
commit ff49673214
1 changed files with 83 additions and 0 deletions
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83
src/backend/vector/ifma/field.rs
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@ -98,8 +98,67 @@ impl FieldElement51x4 {
}
}
impl<'a> Mul<(u32, u32, u32, u32)> for &'a FieldElement51x4 {
type Output = FieldElement51x4;
#[inline]
fn mul(self, scalars: (u32, u32, u32, u32)) -> FieldElement51x4 {
unsafe {
let x = &self.0;
let y = u64x4::new(
scalars.0 as u64,
scalars.1 as u64,
scalars.2 as u64,
scalars.3 as u64,
);
let mask = u64x4::splat((1 << 51) - 1);
let r19 = u64x4::splat(19);
let mut z0lo = u64x4::splat(0);
let mut z1lo = u64x4::splat(0);
let mut z2lo = u64x4::splat(0);
let mut z3lo = u64x4::splat(0);
let mut z4lo = u64x4::splat(0);
let mut z1hi = u64x4::splat(0);
let mut z2hi = u64x4::splat(0);
let mut z3hi = u64x4::splat(0);
let mut z4hi = u64x4::splat(0);
let mut z5hi = u64x4::splat(0);
// Wave 0
z4hi = madd52hi(z4hi, y, x[3]);
z5hi = madd52hi(z5hi, y, x[4]);
z4lo = madd52lo(z4lo, y, x[4]);
z0lo = madd52lo(z0lo, y, x[0]);
z3lo = madd52lo(z3lo, y, x[3]);
z2lo = madd52lo(z2lo, y, x[2]);
z1lo = madd52lo(z1lo, y, x[1]);
z3hi = madd52hi(z3hi, y, x[2]);
// Wave 2
z2hi = madd52hi(z2hi, y, x[1]);
z1hi = madd52hi(z1hi, y, x[0]);
let z4 = z4hi + z4hi + z4lo;
let c4 = z4 >> 51;
let z5 = z5hi + z5hi + c4;
let z3 = z3hi + z3hi + z3lo;
let z2 = z2hi + z2hi + z2lo;
let z1 = z1hi + z1hi + z1lo;
FieldElement51x4([
madd52lo(z0lo & mask, z5, r19),
(z1 & mask) + (z0lo >> 51),
(z2 & mask) + (z1lo >> 51),
(z3 & mask) + (z2lo >> 51),
(z4 & mask) + (z3lo >> 51),
])
}
}
}
impl<'a, 'b> Mul<&'b FieldElement51x4> for &'a FieldElement51x4 {
type Output = FieldElement51x4;
#[inline]
fn mul(self, rhs: &'b FieldElement51x4) -> FieldElement51x4 {
unsafe {
// Inputs
@ -330,4 +389,28 @@ mod test {
assert_eq!(c, splits[i]);
}
}
#[test]
fn iterated_u32_mul_matches_serial() {
// Invert a small field element to get a big one
let a = FieldElement51([2438, 24, 243, 0, 0]).invert();
let b = FieldElement51([121665, 0, 0, 0, 0]);
let mut c = &a * &b;
for i in 0..1024 {
c = &b * &c;
}
let ax4 = FieldElement51x4::new(&a, &a, &a, &a);
let bx4 = (121665u32, 121665u32, 121665u32, 121665u32);
let mut cx4 = &ax4 * bx4;
for i in 0..1024 {
cx4 = &cx4 * bx4;
}
let splits = cx4.split();
for i in 0..4 {
assert_eq!(c, splits[i]);
}
}
}