docs: def smix(B, Bi, r, N, V, X):
      """SMix; a specific case of ROMix based on Salsa20/8"""
  
      X[0:(0)+(32 * r)] = B[Bi:(Bi)+(32 * r)]
  
      for i in xrange(N):                                # ROMix - 2
          V[i * (32 * r):(i * (32 * r))+(32 * r)] = X[0:(0)+(32 * r)]
          blockmix_salsa8(X, 32 * r, r)                  # ROMix - 4
  
      for i in xrange(N):                                # ROMix - 6
          j = integerify(X, r) & (N - 1)                 # ROMix - 7
          blockxor(V, j * (32 * r), X, 0, 32 * r)        # ROMix - 8(inner)
          blockmix_salsa8(X, 32 * r, r)                  # ROMix - 9(outer)
  
      B[Bi:(Bi)+(32 * r)] = X[0:(0)+(32 * r)]