:= 0; i < n; i += 4 { w0 := uint32(v[0]) | uint32(v[1])<<8 | uint32(v[2])<<16 r[i+0] = fieldSubToMontgomery(b, w0&mask18) w1 := uint32(v[2])>>2 | uint32(v[3])<<6 | uint32(v[4])<<14 r[i+1] = fieldSubToMontgomery(b, w1&mask18) w2 := uint32(v[4])>>4 | uint32(v[5])<<4 | uint32(v[6])<<12 r[i+2] = fieldSubToMontgomery(b, w2&mask18) w3 := uint32(v[6])>>6 | uint32(v[7])<<2 | uint32(v[8])<<10 r[i+3] = fieldSubToMontgomery(b, w3&mask18) v = v[4*18/8:] } return r } // bitUnpack20 implements BitUnpack(v, 2¹⁹-1,...