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Optimize mac_digit

This commit is contained in:
Nicolas Kirchner 2017-08-15 21:14:15 +02:00
parent 243bc6fe4c
commit bcd76c55e8
1 changed files with 8 additions and 10 deletions
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18
bigint/src/algorithms.rs
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@ -226,20 +226,18 @@ fn mac_digit(acc: &mut [BigDigit], b: &[BigDigit], c: BigDigit) {
return; return;
} }
let mut b_iter = b.iter();
let mut carry = 0; let mut carry = 0;
for ai in acc.iter_mut() { for (i, bi) in b.iter().enumerate() {
if let Some(bi) = b_iter.next() { acc[i] = mac_with_carry(acc[i], *bi, c, &mut carry);
*ai = mac_with_carry(*ai, *bi, c, &mut carry);
} else if carry != 0 {
*ai = mac_with_carry(*ai, 0, c, &mut carry);
} else {
break;
}
} }
assert!(carry == 0); let mut i = b.len();
while carry != 0 {
acc[i] = adc(acc[i], 0, &mut carry);
i += 1;
}
} }
/// Three argument multiply accumulate: /// Three argument multiply accumulate: