I want tidy code that creates an opcode from two pieces, and encodes it as a little endian binary. Where “the OGF occupies the upper 6 bits of the Opcode, and the OCF occupies the remaining 10 bits.” This code is almost what I want, except that the resulting binary is big endian:

def opcode_bin(ogf, ocf), do: <<ogf::6, ocf::10>>

<<16, 1>> = opcode_bin(4, 1)
# I want <<1, 16>>

The following works, but the intermediate step isn’t very elegant:

def opcode_bin(ogf, ocf) do
  <<opcode::16>> = <<ogf::6, ocf::10>>
  <<opcode::little-16>>
end

Is there a nicer way to accomplish this, maybe by specifying that I want little-endian output directly?