math.big: optimize add_digit_array() (#25139)

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Mike 2025-08-20 08:01:48 +03:00 committed by GitHub
parent 4c4028a84b
commit b502d52280
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@ -45,28 +45,25 @@ fn add_digit_array(operand_a []u64, operand_b []u64, mut sum []u64) {
return
}
// First pass intersects with both operands
smaller_limit := imin(operand_a.len, operand_b.len)
larger_limit := imax(operand_a.len, operand_b.len)
mut a, mut b := if operand_a.len >= operand_b.len {
operand_a, operand_b
} else {
operand_b, operand_a
}
mut carry := u64(0)
for index in 0 .. smaller_limit {
for index in 0 .. b.len {
partial := carry + a[index] + b[index]
sum[index] = u64(partial) & max_digit
carry = u64(partial >> digit_bits)
sum[index] = partial & max_digit
carry = partial >> digit_bits
}
for index in smaller_limit .. larger_limit {
for index in b.len .. a.len {
partial := carry + a[index]
sum[index] = u64(partial) & max_digit
carry = u64(partial >> digit_bits)
sum[index] = partial & max_digit
carry = partial >> digit_bits
}
sum[larger_limit] = carry
sum[a.len] = carry
shrink_tail_zeros(mut sum)
}