Vol. 3B 22-1
CHAPTER 22
ARCHITECTURE COMPATIBILITY
Intel 64 and IA-32 processors are binary compatible. Compatibility means that, within limited constraints,
programs that execute on previous generations of processors will produce identical results when executed on later
processors. The compatibility constraints and any implementation differences between the Intel 64 and IA-32
processors are described in this chapter.
Each new processor has enhanced the software visible architecture from that found in earlier Intel 64 and IA-32
processors. Those enhancements have been defined with consideration for compatibility with previous and future
processors. This chapter also summarizes the compatibility considerations for those extensions.
22.1
PROCESSOR FAMILIES AND CATEGORIES
IA-32 processors are referred to in several different ways in this chapter, depending on the type of compatibility
information being related, as described in the following:
•
IA-32 Processors — All the Intel processors based on the Intel IA-32 Architecture, which include the
8086/88, Intel 286, Intel386, Intel486, Pentium, Pentium Pro, Pentium II, Pentium III, Pentium 4, and Intel
Xeon processors.
•
32-bit Processors — All the IA-32 processors that use a 32-bit architecture, which include the Intel386,
Intel486, Pentium, Pentium Pro, Pentium II, Pentium III, Pentium 4, and Intel Xeon processors.
•
16-bit Processors — All the IA-32 processors that use a 16-bit architecture, which include the 8086/88 and
Intel 286 processors.
•
P6 Family Processors — All the IA-32 processors that are based on the P6 microarchitecture, which include
the Pentium Pro, Pentium II, and Pentium III processors.
•
Pentium
®
4 Processors — A family of IA-32 and Intel 64 processors that are based on the Intel NetBurst
®
microarchitecture.
•
Intel
®
Pentium
®
M Processors — A family of IA-32 processors that are based on the Intel Pentium M
processor microarchitecture.
•
Intel
®
Core™ Duo and Solo Processors — Families of IA-32 processors that are based on an improved Intel
Pentium M processor microarchitecture.
•
Intel
®
Xeon
®
Processors — A family of IA-32 and Intel 64 processors that are based on the Intel NetBurst
microarchitecture. This family includes the Intel Xeon processor and the Intel Xeon processor MP based on the
Intel NetBurst microarchitecture. Intel Xeon processors 3000, 3100, 3200, 3300, 3200, 5100, 5200, 5300,
5400, 7200, 7300 series are based on Intel Core microarchitectures and support Intel 64 architecture.
•
Pentium
®
D Processors — A family of dual-core Intel 64 processors that provides two processor cores in a
physical package. Each core is based on the Intel NetBurst microarchitecture.
•
Pentium
®
Processor Extreme Editions — A family of dual-core Intel 64 processors that provides two
processor cores in a physical package. Each core is based on the Intel NetBurst microarchitecture and supports
Intel Hyper-Threading Technology.
•
Intel
®
Core™ 2 Processor family— A family of Intel 64 processors that are based on the Intel Core microar-
chitecture. Intel Pentium Dual-Core processors are also based on the Intel Core microarchitecture.
•
Intel
®
Atom™ Processors — A family of IA-32 and Intel 64 processors. 45 nm Intel Atom processors are
based on the Intel Atom microarchitecture. 32 nm Intel Atom processors are based on newer microarchitec-
tures including the Silvermont microarchitecture and the Airmont microarchitecture. Each generation of Intel
Atom processors can be identified by the CPUID’s DisplayFamily_DisplayModel signature; see Table 35-1
“CPUID Signature Values of DisplayFamily_DisplayModel”.