ISO/IEC 11889-4:2015包含描述ISO/IEC 11889-3中命令代码使用的算法和方法的C代码。ISO/IEC 11889-4:2015中的代码扩充了ISO/IEC 11889-2和ISO/IEC 11889-3，以提供TPM的完整描述，包括执行命令操作的代码的支持框架。 ISO/IEC 11889-4:2015中的任何代码可替换为在与ISO/IEC 11889-3中的操作代码接口时提供类似结果的代码。本ISO/IEC 11889-4:2015中未包含在附录中的规范行为是规范性的，正如在与ISO/IEC 11889-3规范的接口处所观察到的那样。附录中的代码是为了完整性而提供的，也就是说，允许根据提供的代码全面实施ISO/IEC 11889。 ISO/IEC 11889-3和本ISO/IEC 11889-4:2015中的代码旨在定义合规TPM的行为。在某些情况下（例如固件更新），不可能提供符合要求的实施。在这些情况下，供应商提供的满足ISO/IEC 11889-3中提供的功能一般描述的任何实现都将符合要求。 ISO/IEC 11889-3和本ISO/IEC 11889-4:2015中的代码不是为了满足任何特定的一致性水平而编写的，ISO/IEC 11889也不要求TPM满足任何特定的一致性水平。

ISO/IEC 11889-4:2015 contains C code that describes the algorithms and methods used by the command code in ISO/IEC 11889-3. The code in ISO/IEC 11889-4:2015 augments ISO/IEC 11889-2 and ISO/IEC 11889-3 to provide a complete description of a TPM, including the supporting framework for the code that performs the command actions. Any code in ISO/IEC 11889-4:2015 may be replaced by code that provides similar results when interfacing to the action code in ISO/IEC 11889-3. The behavior of code in this ISO/IEC 11889-4:2015 that is not included in an annex is normative, as observed at the interfaces with ISO/IEC 11889-3 code. Code in an annex is provided for completeness, that is, to allow a full implementation of ISO/IEC 11889 from the provided code. The code in ISO/IEC 11889-3 and this ISO/IEC 11889-4:2015 is written to define the behavior of a compliant TPM. In some cases (e.g., firmware update), it is not possible to provide a compliant implementation. In those cases, any implementation provided by the vendor that meets the general description of the function provided in ISO/IEC 11889-3 would be compliant. The code in ISO/IEC 11889-3 and this ISO/IEC 11889-4:2015 is not written to meet any particular level of conformance nor does ISO/IEC 11889 require that a TPM meet any particular level of conformance.