X_PRIVATE_BITS
for (t = X_PRIVATE_BITS - 1; t >= 0; t--) {
else if (t == X_PRIVATE_BITS - 1)
scalar2[X_PRIVATE_BYTES - 1] &= ~((0u - 1u) << ((X_PRIVATE_BITS + 7) % 8));
scalar2[X_PRIVATE_BYTES - 1] |= 1 << ((X_PRIVATE_BITS + 7) % 8);