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Reorganize AVX2 point code

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This commit is contained in:
Henry de Valence 2018-03-26 17:35:08 -07:00
parent e8b053b281
commit 7ef6a1e6fa
5 changed files with 68 additions and 77 deletions
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128
src/backend/avx2/edwards.rs
View file

@ -24,7 +24,7 @@ use subtle::Choice;
use edwards;
use scalar::Scalar;
use scalar_mul::window::LookupTable;
use scalar_mul::window::{LookupTable, OddLookupTable};
use traits::Identity;
@ -76,62 +76,6 @@ impl Identity for ExtendedPoint {
}
}
/// A cached point with some precomputed variables used for readdition.
#[derive(Copy, Clone, Debug)]
pub struct CachedPoint(pub(super) FieldElement32x4);
impl From<ExtendedPoint> for CachedPoint {
fn from(P: ExtendedPoint) -> CachedPoint {
let mut x = P.0;
// x = (S2 S3 Z2 T2)
x.diff_sum(0b00001111);
// x = (121666*S2 121666*S3 2*121666*Z2 2*121665*T2)
x.scale_by_curve_constants();
// x = (121666*S2 121666*S3 2*121666*Z2 -2*121665*T2)
x.negate(D_LANES);
CachedPoint(x)
}
}
impl Default for CachedPoint {
fn default() -> CachedPoint {
CachedPoint::identity()
}
}
impl Identity for CachedPoint {
fn identity() -> CachedPoint {
CachedPoint(FieldElement32x4([
u32x8::new(121647, 121666, 0, 0, 243332, 67108845, 0, 33554431),
u32x8::new(67108864, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
]))
}
}
impl ConditionallyAssignable for CachedPoint {
fn conditional_assign(&mut self, other: &CachedPoint, choice: Choice) {
self.0.conditional_assign(&other.0, choice);
}
}
impl<'a> Neg for &'a CachedPoint {
type Output = CachedPoint;
fn neg(self) -> CachedPoint {
let mut neg = *self;
neg.0.swap_AB();
neg.0.negate_lazy(D_LANES);
neg
}
}
impl ExtendedPoint {
pub fn double(&self) -> ExtendedPoint {
unsafe {
@ -236,6 +180,62 @@ impl ExtendedPoint {
}
}
/// A cached point with some precomputed variables used for readdition.
#[derive(Copy, Clone, Debug)]
pub struct CachedPoint(pub(super) FieldElement32x4);
impl From<ExtendedPoint> for CachedPoint {
fn from(P: ExtendedPoint) -> CachedPoint {
let mut x = P.0;
// x = (S2 S3 Z2 T2)
x.diff_sum(0b00001111);
// x = (121666*S2 121666*S3 2*121666*Z2 2*121665*T2)
x.scale_by_curve_constants();
// x = (121666*S2 121666*S3 2*121666*Z2 -2*121665*T2)
x.negate(D_LANES);
CachedPoint(x)
}
}
impl Default for CachedPoint {
fn default() -> CachedPoint {
CachedPoint::identity()
}
}
impl Identity for CachedPoint {
fn identity() -> CachedPoint {
CachedPoint(FieldElement32x4([
u32x8::new(121647, 121666, 0, 0, 243332, 67108845, 0, 33554431),
u32x8::new(67108864, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
u32x8::new(67108863, 0, 33554431, 0, 0, 67108863, 0, 33554431),
]))
}
}
impl ConditionallyAssignable for CachedPoint {
fn conditional_assign(&mut self, other: &CachedPoint, choice: Choice) {
self.0.conditional_assign(&other.0, choice);
}
}
impl<'a> Neg for &'a CachedPoint {
type Output = CachedPoint;
fn neg(self) -> CachedPoint {
let mut neg = *self;
neg.0.swap_AB();
neg.0.negate_lazy(D_LANES);
neg
}
}
impl<'a, 'b> Add<&'b CachedPoint> for &'a ExtendedPoint {
type Output = ExtendedPoint;
@ -288,8 +288,9 @@ impl<'a, 'b> Sub<&'b CachedPoint> for &'a ExtendedPoint {
}
}
impl From<ExtendedPoint> for LookupTable<CachedPoint> {
fn from(P: ExtendedPoint) -> Self {
impl<'a> From<&'a edwards::EdwardsPoint> for LookupTable<CachedPoint> {
fn from(point: &'a edwards::EdwardsPoint) -> Self {
let P = ExtendedPoint::from(*point);
let mut points = [CachedPoint::from(P); 8];
for i in 0..7 {
points[i+1] = (&P + &points[i]).into();
@ -298,11 +299,10 @@ impl From<ExtendedPoint> for LookupTable<CachedPoint> {
}
}
use scalar_mul::window::OddLookupTable;
impl<'a> From<&'a ExtendedPoint> for OddLookupTable<CachedPoint> {
fn from(A: &'a ExtendedPoint) -> Self {
let mut Ai = [CachedPoint::from(*A); 8];
impl<'a> From<&'a edwards::EdwardsPoint> for OddLookupTable<CachedPoint> {
fn from(point: &'a edwards::EdwardsPoint) -> Self {
let A = ExtendedPoint::from(*point);
let mut Ai = [CachedPoint::from(A); 8];
let A2 = A.double();
for i in 0..7 {
Ai[i + 1] = (&A2 + &Ai[i]).into();

5
src/backend/avx2/scalar_mul/straus.rs
View file

@ -31,10 +31,7 @@ where
// for each input point P
let lookup_tables: Vec<_> = points
.into_iter()
.map(|point| {
let avx2_point = ExtendedPoint::from(*point.borrow());
LookupTable::<CachedPoint>::from(avx2_point)
})
.map(|point| LookupTable::<CachedPoint>::from(point.borrow()))
.collect();
let scalar_digits_vec: Vec<_> = scalars

4
src/backend/avx2/scalar_mul/variable_base.rs
View file

@ -8,10 +8,8 @@ use scalar_mul::window::LookupTable;
/// Perform constant-time, variable-base scalar multiplication.
pub fn mul(point: &EdwardsPoint, scalar: &Scalar) -> EdwardsPoint {
// XXX combine these conversions
let avx2_point = ExtendedPoint::from(*point);
// Construct a lookup table of [P,2P,3P,4P,5P,6P,7P,8P]
let lookup_table = LookupTable::<CachedPoint>::from(avx2_point);
let lookup_table = LookupTable::<CachedPoint>::from(point);
// Setting s = scalar, compute
//
// s = s_0 + s_1*16^1 + ... + s_63*16^63,

3
src/backend/avx2/scalar_mul/vartime_double_base.rs
View file

@ -30,8 +30,7 @@ pub fn mul(a: &Scalar, A: &EdwardsPoint, b: &Scalar) -> EdwardsPoint {
}
}
let avx2_A = ExtendedPoint::from(*A);
let table_A = OddLookupTable::<CachedPoint>::from(&avx2_A);
let table_A = OddLookupTable::<CachedPoint>::from(A);
let table_B = &BASEPOINT_ODD_LOOKUP_TABLE;
let mut Q = ExtendedPoint::identity();

5
src/backend/avx2/scalar_mul/vartime_straus.rs
View file

@ -31,10 +31,7 @@ where
.collect();
let lookup_tables: Vec<_> = points
.into_iter()
.map(|point| {
let avx2_point = ExtendedPoint::from(*point.borrow());
OddLookupTable::<CachedPoint>::from(&avx2_point)
})
.map(|point| OddLookupTable::<CachedPoint>::from(point.borrow()))
.collect();
let mut Q = ExtendedPoint::identity();