Overview/History of Architecture

By the late 20th century, Intel's x86 processors (running on IA-32 architecture) were obsolete compared with modern design and technology. In the 1970's, the IA-32 architecture was designed around a relatively small number of transistors. Intel decided to design a new processor architecture based around the ability to fit several million transistors on a single chip. The result was the IA-64 architecture, developed jointly with Hewlett-Packard.

This new architecture was first used in a processor called the Itanium, unveiled in May 2001. The Itanium ran at up to 800 MHz, but it's performance compared to equivalent x86 processors was only a slight improvement. And while the architecture was backward compatible with IA-32 instruction, it's performance of running that instruction was actually worse!

Intel and HP attempted to correct the problems in their next model, the Itanium 2, first released in June 2002. The Itanium 2 improved its performance, and several new versions released over the next couple of years continued to improve the architecture.

Main Innovations:

Rich Instruction Set

Bundled Execution

Predicated Instructions

Large Register Files

 -Register Stack

 -Rotating Registers

Modulo Scheduled Loops

Control/Data Speculation

Cache Control Instructions

High-precision Floating-Point