2²⁸-1] w0 := b - fieldCenteredMod(r[i]) v[0] = byte(w0 << 0) v[1] = byte(w0 >> 8) v[2] = byte(w0 >> 16) w1 := b - fieldCenteredMod(r[i+1]) v[2] |= byte(w1 << 2) v[3] = byte(w1 >> 6) v[4] = byte(w1 >> 14) w2 := b - fieldCenteredMod(r[i+2]) v[4] |= byte(w2 << 4) v[5] = byte(w2 >> 4) v[6] = byte(w2 >> 12) w3 := b - fieldCenteredMod(r[i+3]) v[6] |= byte(w3 << 6) v[7] = byte(w3 >> 2) v[8] = byte(w3 >> 10) v = v[4*18/8:] } return out } // bitPack20 implements BitPack(r mod± q, 2¹⁹-1, 2¹⁹), which packs...