text: #ifndef _opcodes_h
  #define _opcodes_h
  
  // op_code functions
  void op_0000(unsigned short opcode);
  void op_1000(unsigned short opcode);
  void op_2000(unsigned short opcode);
  void op_3000(unsigned short opcode);
  void op_4000(unsigned short opcode);
  void op_5000(unsigned short opcode);
  void op_6000(unsigned short opcode);
  void op_7000(unsigned short opcode);
  void op_8000(unsigned short opcode);
  void op_9000(unsigned short opcode);
  void op_A000(unsigned short opcode);
  void op_B000(unsigned short opcode);
  void op_C000(unsigned short opcode);
  void op_D000(unsigned short opcode);
  void op_E000(unsigned short opcode);
  void op_F000(unsigned short opcode);
  #endif