make gcd use divrem

[oscardssmith]

No description provided.

[ianatol]

I don't have much context, but should we do something similar here?

julia/base/intfuncs.jl

Lines 769 to 770 in 209a7d9

	a[i] = digits[1 + (rem(x, b) % Int)::Int]
	x = div(x,b)

[oscardssmith]

We can actually do better there. Since there are only 60 possible divisors, we could use one of the fancy division by a constant integer algorithms (see https://en.algorithmica.org/hpc/arithmetic/division/)

[oscardssmith]

And because Julia is awesome, this is just

function _base(base::Integer, x::Integer, pad::Int, neg::Bool)
    (x >= 0) | (base < 0) || throw(DomainError(x, "For negative `x`, `base` must be negative."))
    2 <= abs(base) <= 62 || throw(DomainError(base, "base must satisfy 2 ≤ abs(base) ≤ 62"))
    b = (base % Int)::Int
    b = Base.MultiplicativeInverses.multiplicativeinverse(b)
    digits = abs(b) <= 36 ? base36digits : base62digits
    n = neg + ndigits(x, base=b, pad=pad)
    a = StringVector(n)
    i = n
    @inbounds while i > neg
        if b > 0
            q,r = divrem(x,b)
            a[i] = digits[1 + (r % Int)::Int]
            x = q
        else
            a[i] = digits[1 + (mod(x, -b) % Int)::Int]
            x = cld(x,b)
        end
        i -= 1
    end
    if neg; @inbounds a[1]=0x2d; end
    String(a)
end

[oscardssmith]

merging tomorrow sans objections.