1.1. Processor Architecture

The Itanium™ Architecture is specified by the following documents

• Itanium ™ Architecture Software Developer's Manual Volume 1

• Itanium ™ Architecture Software Developer's Manual Volume 2

• Itanium ™ Architecture Software Developer's Manual Volume 3

• Itanium ™ Architecture Software Developer's Manual Volume 4

• Itanium ™ Software Conventions and Runtime Guide

• Intel® Itanium ™ Processor-specific Application Binary Interface

Only the features of the Itanium™ processor instruction set may be assumed to be present. An application is responsible for determining 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.

Only instructions which do not require elevated privileges may be used.

Applications may not make system calls directly. The interfaces in the C library must be used instead.

There are some features of the Itanium™ processor architecture that need not be supported by a conforming implementation. These are described in this chapter. A conforming application shall not rely on these features.

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

This specification describes only LP64 (i.e. 32-bit integers, 64-bit longs and pointers) based implementations. Implementations may also provide ILP32 (32-bit integers, longs, and pointers), but conforming applications shall not rely on support for ILP32. See section 1.2 of the Intel® Itanium ™ Processor-specific Application Binary Interface for further information.