log10

    pub fn log10(a: Const, limbs_buffer: []Limb) Limb {
        assert(a.positive);
        assert(!a.eqlZero());
        const limb_base_as_bigint: Const = .{ .limbs = &.{constants.big_bases[10]}, .positive = true };

        var q: Mutable = .{
            .limbs = limbs_buffer[0 .. a.limbs.len + 2],
            .positive = true,
            .len = a.limbs.len,
        };
        @memcpy(q.limbs[0..a.limbs.len], a.limbs);

        var remainder: Mutable = .{
            .limbs = limbs_buffer[q.limbs.len..][0..a.limbs.len],
            .positive = true,
            .len = 1,
        };

        const division_buf = limbs_buffer[q.limbs.len + remainder.limbs.len ..];

        var num_digits: Limb = 0;
        while (q.len >= 2) {
            q.divTrunc(&remainder, q.toConst(), limb_base_as_bigint, division_buf);
            num_digits += constants.digits_per_limb[10];
        }
        var remaining_limb = q.limbs[0];
        while (remaining_limb != 0) {
            remaining_limb /= 10;
            num_digits += 1;
        }

        return num_digits - 1;
    }