Chapter 8. Low Level System Information

8.1. Machine Interface

8.1.1. Processor Architecture

The PowerPC Architecture is specified by the following documents:

Only the features of the PowerPC Power3 processor instruction set may be assumed to be present. An application should determine if any additional instruction set features are available before using those additional features. If a feature is not present, then the application may not use it.

Conforming applications may use only instructions which do not require elevated privileges.

Conforming applications shall not invoke the implementations underlying system call interface directly. The interfaces in the implementation base libraries shall be used instead.

Rationale: Implementation-supplied base libraries may use the system call interface but applications must not assume any particular operating system or kernel version is present.

An implementation must support the 64-bit computation mode as described in The PowerPC™ Microprocessor Family.

Applications conforming to this specification must provide feedback to the user if a feature that is required for correct execution of the application is not present. Applications conforming to this specification should attempt to execute in a diminished capacity if a required feature is not present.

This specification does not provide any performance guarantees of a conforming system. A system conforming to this specification may be implemented in either hardware or software.

8.1.2. Data Representation

LSB-conforming applications shall use the data representation as defined in Chapter 3 of the 64-bit PowerPC™ ELF ABI Supplement.

8.1.3. Byte Ordering

LSB-conforming applications shall use big-endian byte ordering. LSB-conforming implementations may support little-endian applications.

8.1.4. Fundamental Types

LSB-conforming applications shall use the fundamental types as defined in Chapter 3 of the 64-bit PowerPC™ ELF ABI Supplement.

LSB-conforming applications shall not use the long double fundamental type.