Intel 64 and IA-32 Architectures Software Developers Manual Volume 1, Basic Architecture

2-20 Vol. 1
INTEL
®
64 AND IA-32 ARCHITECTURES
• 8 additional general-purpose registers (GPRs)
• 8 additional registers for streaming SIMD extensions (SSE, SSE2, SSE3 and
SSSE3)
• 64-bit-wide GPRs and instruction pointers
• uniform byte-register addressing
• fast interrupt-prioritization mechanism
• a new instruction-pointer relative-addressing mode
An Intel 64 architecture processor supports existing IA-32 software because it is able
to run all non-64-bit legacy modes supported by IA-32 architecture. Most existing
IA-32 applications also run in compatibility mode.
2.2.8 Intel
®
Virtualization Technology (Intel
®
VT)
Intel
®
Virtualization Technology for Intel 64 and IA-32 architectures provide exten-
sions that support virtualization. The extensions are referred to as Virtual Machine
Extensions (VMX). An Intel 64 or IA-32 platform with VMX can function as multiple
virtual systems (or virtual machines). Each virtual machine can run operating
systems and applications in separate partitions.
VMX also provides programming interface for a new layer of system software (called
the Virtual Machine Monitor (VMM)) used to manage the operation of virtual
machines. Information on VMX and on the programming of VMMs is in Intel® 64
and IA-32 Architectures Software Developer’s Manual, Volume 3B. Chapter 5, “VMX
Instruction Reference,” in the Intel® 64 and IA-32 Architectures Software Devel-
oper’s Manual, Volume 2B, provides information on VMX instructions.
2.3 INTEL
®
64 AND IA-32 PROCESSOR GENERATIONS
In the mid-1960s, Intel cofounder and Chairman Emeritus Gordon Moore had this
observation: “the number of transistors that would be incorporated on a silicon die
would double every 18 months for the next several years.” Over the past three and
half decades, this prediction known as “Moore's Law” has continued to hold true.
The computing power and the complexity (or roughly, the number of transistors per
processor) of Intel architecture processors has grown in close relation to Moore's law.
By taking advantage of new process technology and new microarchitecture designs,
each new generation of IA-32 processors has demonstrated frequency-scaling head-
room and new performance levels over the previous generation processors.
The key features of the Intel Pentium 4 processor, Intel Xeon processor, Intel Xeon
processor MP, Pentium III processor, and Pentium III Xeon processor with advanced
transfer cache are shown in Table 2-1. Older generation IA-32 processors, which do
not employ on-die Level 2 cache, are shown in Table 2-2.