for name in ('ax', 'bx', 'cx', 'dx', 'si', 'di', 'bp', 'ip', 'sp', 'r8w', 'r9w', 'r10w', 'r11w', 'r12w', 'r13w', 'r14w', 'r15w'):
  registers[name] = register_t(name, SIZE_16, WORD)