aureooms/js-integer-little-endian

export function bmul_t (r){

    /**
     * Computes product of two big endian arrays.
     * <p>
     * Computes product of two big endian arrays
     * using long multiplication algorithm (the one teached in
     * european primary schools)
     */

    var mul = function(a, ai, aj, b, bi, bj, c, ci, cj){
        var ak, ck = --cj, ct, t, u, v, w, y, z;

        while (bj --> bi && ck >= ci) {
            for (ak = aj, w = 0; ak --> ai && ck >= ci; --ck) {
                t = b[bj] * a[ak];
                u = t % r;
                v = c[ck] + u + w;

                y = v % r;

                c[ck] = y;

                z = (v - y) / r;

                for (ct = ck - 1; z > 0 && ct >= ci; --ct) {
                    v = c[ct] + z;
                    y = v % r;
                    c[ct] = y;
                    z = (v - y) / r;
                }

                w = (t - u) / r;
            }
            ck = --cj;
        }
    };

    return mul;

}