switch p.arch.Family {
	case sys.ARM64:
		err := arm64.EncodeRegisterExtension(a, ext, reg, num, isAmount, isIndex)
		if err != nil {
			p.errorf("%v", err)
		}
	case sys.Loong64:
		err := arch.Loong64RegisterExtension(a, ext, reg, num, isAmount, isIndex)
		if err != nil {
			p.errorf("%v", err)
		}
	default:
		p.errorf("register extension not supported on this architecture")
	}
}