Instruction Set Transition Model; System Environment; Major Operating Environments - Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual

Figure 2-1.
Table 2-1.
System
Environment
Itanium System
Environment
2.2 Instruction Set Transition Model Overview
Within the Itanium System Environment, the processor can execute either IA-32 or
Itanium instructions at any time. Three special instructions and interruptions are
defined to transition the processor between the IA-32 and the Itanium instruction set.
• jmpe (IA-32 instruction) Jump to an Itanium target instruction, and transition to the
Itanium instruction set.
• br.ia (Itanium instruction) Branch to an IA-32 target instruction, and change the
instruction set to IA-32.
• rfi (Itanium instruction) "Return from interruption" is defined to return to an IA-32
or Itanium instruction.
• Interrupts transition the processor to the Itanium instruction set for all interrupt
conditions.
1:14

System Environment

®
Intel Itanium
IA-32 Instructions
Segmentation

Major Operating Environments

Application
Environment
IA-32 Protected Mode IA-32 Protected Mode applications in the Intel
Environment.
IA-32 Real Mode IA-32 Real Mode applications in the Intel
Environment.
IA-32 Virtual Mode IA-32 Virtual 86 Mode applications in the Intel
Environment.
® ®
Intel Itanium Itanium architecture-based applications on Intel
Instruction Set architecture-based operating systems.
Volume 1, Part 1: Introduction to the Intel
®
System Environment
®
Itanium
Instructions
Paging
& Interruption
Handling
®
in the Intel Itanium
Architecture
Usage
®
® ®
Itanium System
® ®
Itanium System
® ®
Itanium System
®
Itanium
® ®
Itanium Architecture