src/api/arithmetic/add/add.js

import _add from '../../../core/arithmetic/add/_add.js';

/**
 * Adds two big endian arrays and puts result in a destination array.
 * Wraps on overflow. Works with any combination of array sizes.
 *
 * @param {Number} r base (radix)
 * @param {Array} a first operand
 * @param {Number} ai a left
 * @param {Number} aj a right
 * @param {Array} b second operand
 * @param {Number} bi b left
 * @param {Number} bj b right
 * @param {Array} c result, must be 0 initialized
 * @param {Number} ci c left
 * @param {Number} cj c right
 *
 */
export default function add(r, a, ai, aj, b, bi, bj, c, ci, cj) {
	ci = Math.max(0, ci);
	const k = cj - ci;

	ai = Math.max(0, ai, aj - k);
	bi = Math.max(0, bi, bj - k);
	const m = aj - ai;
	const n = bj - bi;

	return m < n
		? _add(r, b, bi, bj, a, ai, aj, c, ci, cj)
		: _add(r, a, ai, aj, b, bi, bj, c, ci, cj);
}