Deviations from the original PowerPC Architecture offer flexibility to allow for enhancements that may come over time. In addition, IBM has defined its own Virtual Environment and Operating Environment levels for its PowerPC 400 family of embedded controllers. A new PowerPC architecture update has been developed. All of these enhancements address the needs of embedded systems. Also, PowerPC implementations can handle string operations for multi-byte strings up to 128 bytes in length.
All storage is byte addressable.
For misaligned data accesses, alignment support varies by product family, with some taking exceptions and others handling the access through multiple operations in hardware. Support for little endian varies by implementation. Classic PowerPC had minimal support, while the 400 family provides more robust support for little endian storage. Book E is endian-neutral, as the Book E architecture fully supports both accessing method. The three classes are explained below.