@Override
    public DecodedInstruction decode(int opcodeUnit, CodeInput in) throws EOFException {
      int opcode = byte0(opcodeUnit);
      int literal = byte1(opcodeUnit); // should be zero
      int a = in.read();
      int b = in.read();
      return new TwoRegisterDecodedInstruction(this, opcode, 0, null, 0, literal, a, b);
    }
Representation of an instruction format, which knows how to decode into and encode from instances
of {@link DecodedInstruction}.
android/android_framework/dex-maker/src/main/java/com/android/dx/io/instructions/InstructionCodec.java