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Better variable names

This commit is contained in:
Eirik Ogilvie-Wigley 2018-09-10 02:23:54 -06:00
parent af44c5da70
commit ecf2c11b51
1 changed files with 15 additions and 15 deletions
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30
src/fq.rs
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@ -60,22 +60,22 @@ const MODULUS: Fq = Fq([
/// Compute a + b + carry, returning the result the new carry over.
#[inline(always)]
fn adc(a: u64, b: u64, carry: u64) -> (u64, u64) {
let adc = u128::from(a) + u128::from(b) + u128::from(carry);
(adc as u64, (adc >> 64) as u64)
let ret = u128::from(a) + u128::from(b) + u128::from(carry);
(ret as u64, (ret >> 64) as u64)
}
/// Compute a - (b + carry), returning the result and the carry over
/// Compute a - (b + borrow), returning the result and the new borrow.
#[inline(always)]
fn sbb(a: u64, b: u64, carry: u64) -> (u64, u64) {
let sbb = u128::from(a).wrapping_sub(u128::from(b) + u128::from(carry >> 63));
(sbb as u64, (sbb >> 64) as u64)
fn sbb(a: u64, b: u64, borrow: u64) -> (u64, u64) {
let ret = u128::from(a).wrapping_sub(u128::from(b) + u128::from(borrow >> 63));
(ret as u64, (ret >> 64) as u64)
}
/// Compute a + (b * c) + carry, returning the result and the new carry over.
#[inline(always)]
fn mac(a: u64, b: u64, c: u64, carry: u64) -> (u64, u64) {
let mac = u128::from(a) + (u128::from(b) * u128::from(c)) + u128::from(carry);
(mac as u64, (mac >> 64) as u64)
let ret = u128::from(a) + (u128::from(b) * u128::from(c)) + u128::from(carry);
(ret as u64, (ret >> 64) as u64)
}
impl<'a> Neg for &'a Fq {
@ -101,14 +101,14 @@ impl<'a> Neg for &'a Fq {
impl<'b> SubAssign<&'b Fq> for Fq {
fn sub_assign(&mut self, rhs: &'b Fq) {
let (d0, carry) = sbb(self.0[0], rhs.0[0], 0);
let (d1, carry) = sbb(self.0[1], rhs.0[1], carry);
let (d2, carry) = sbb(self.0[2], rhs.0[2], carry);
let (d3, carry) = sbb(self.0[3], rhs.0[3], carry);
let (d0, borrow) = sbb(self.0[0], rhs.0[0], 0);
let (d1, borrow) = sbb(self.0[1], rhs.0[1], borrow);
let (d2, borrow) = sbb(self.0[2], rhs.0[2], borrow);
let (d3, borrow) = sbb(self.0[3], rhs.0[3], borrow);
// If underflow occurred on the final limb, carry = 0x111...111, otherwise
// carry = 0x000...000. Thus, we use it as a mask to conditionally add the modulus.
let borrow_mask = carry;
// If underflow occurred on the final limb, borrow = 0x111...111, otherwise
// borrow = 0x000...000. Thus, we use it as a mask to conditionally add the modulus.
let borrow_mask = borrow;
let (d0, carry) = adc(d0, MODULUS.0[0] & borrow_mask, 0);
let (d1, carry) = adc(d1, MODULUS.0[1] & borrow_mask, carry);