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Support for more backends #797
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} | ||
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pub(super) const fn mul_without_cond_subtract(mut self, other: &Self) -> (bool, Self) { | ||
let (mut lo, mut hi) = ([0u64; N], [0u64; N]); |
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Why not using the MulBuffer
helper here for an easier manipulation?
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Good question, it's been a while since I looked at this code =)
This is the basically tackling #769 (comment) right? |
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Looks good, just some minor comments
// We compute this as follows. | ||
// First, MODULUS mod 2^64 is just the lower 64 bits of MODULUS. | ||
// Hence MODULUS mod 2^64 = MODULUS.0[0] mod 2^64. | ||
// |
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As a follow-up to this PR, the next step would be to rename this existing BigInt
to BigInt64
, and then also add a BigInt32
, correct?
/// Does the modulus have a spare unused bit (i.e., the MSB is 0) | ||
/// | ||
/// This condition applies if | ||
/// (a) `Self::MODULUS[N-1] >> 63 == 0` |
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The comment Self::MODULUS[N-1] >> 63 == 0
would (later) need to be changed to reflect that the underlying representation might be other than an array of u64
s.
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/// (MODULUS + 1) / 4 when MODULUS % 4 == 3. Used for square root precomputations. | ||
/// | ||
/// Can be computed if the `BigInt` type has a `plus_one_div_four` method. |
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And otherwise?
Do you mean if plus_one_div_four
returns Some(...)
?
Description
closes: #XXXX
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