o am has enough room later
            x[x.t++] = 0;
        for (var i = 0; i < this.m.t; ++i) {
            // faster way of calculating u0 = x[i]*mp mod DV
            var j = x[i] & 0x7fff;
            var u0 = (j * this.mpl + (((j * this.mph + (x[i] >> 15) * this.mpl) & this.um) << 15)) & x.DM;
            // use am to combine the multiply-shift-add into one call
            j = i + this.m.t;
            x[j] += this.m.am(0, u0, x, i, 0, this.m.t);
            // propagate carry
            while (x[j]