Volume 1, Part 2: Introduction to Programming for the Intel
®
Itanium
®
Architecture
1:139
Introduction to Programming for the Intel
®
Itanium
®
Architecture
2
2.1
Overview
The Itanium instruction set is designed to allow the compiler to communicate
information to the processor to manage resource characteristics such as instruction
latency, issue width, and functional unit assignment. Although such resources can be
statically scheduled, the Itanium architecture does not require that code be written for
a specific microarchitecture implementation in order to be functional.
The Itanium architecture includes a complete instruction set with new features
designed to:
• Increase instruction-level parallelism (ILP).
• Better manage memory latencies.
• Improve branch handling and management of branch resources.
• Reduce procedure call overhead.
The architecture also enables high floating-point performance and provides direct
support for multimedia applications.
Complete descriptions of the syntax and semantics of Itanium instructions can be found
in
. Though this chapter provides
a high level introduction to application level programming, it assumes prior experience
with assembly language programming as well as some familiarity with the Itanium
application architecture. Optimization is explored in other chapters of this guide.
2.2
Registers
The architecture defines 128 general purpose registers, 128 floating-point registers, 64
predicate registers, and up to 128 special purpose registers. The large number of
architectural registers enable multiple computations to be performed without having to
frequently spill and fill intermediate data to memory.
There are 128, 64-bit
general purpose registers
(
r0-r127
) that are used to hold
values for integer and multimedia computations. Each of the 128 registers has one
additional NaT (Not a Thing) bit which is used to indicate whether the value stored in
the register is valid. Execution of Itanium speculative instructions can result in a
register’s NaT bit being set. Register
r0
is read-only and contains a value of zero (0).
Attempting to write to
r0
will cause a fault.
There are 128, 82-bit
floating-point registers
(
f0-f127
) that are used for
floating-point computations. The first two registers,
f0
and
f1
, are read-only and read
as +0.0 and +1.0, respectively. Instructions that write to
f0
or
f1
will fault.
Summary of Contents for ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Page 1: ......
Page 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Page 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Page 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Page 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Page 230: ......
Page 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Page 380: ...2 132 Volume 2 Part 1 Interruptions ...
Page 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Page 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Page 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Page 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Page 808: ...2 560 Volume 2 Part 2 Context Management ...
Page 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Page 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Page 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Page 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Page 891: ......
Page 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Page 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Page 1296: ......
Page 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...