Intel 64 and IA-32 Architectures Software Developers Manual Volume 3A, System Programming Guide, Part 1

Vol. 3A 17-1
CHAPTER 17
ARCHITECTURE COMPATIBILITY
Intel 64 and IA-32 processors are binary compatible. Compatibility means that,
within limited constraints, programs that execute on previous generations of proces-
sors will produce identical results when executed on later processors. The compati-
bility 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.
17.1 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 Archi-
tecture, 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 Family Processors — A family of IA-32 processors that is based on
the Intel NetBurst microarchitecture.
• Intel Xeon Family Processors — A family of IA-32 processors that is based on
the Intel NetBurst microarchitecture. This family includes the Intel Xeon
processor and the Intel Xeon processor MP.
• Pentium D Processors — A family of dual-core IA-32 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 IA-32
processors that provides two processor cores in a physical package. Each core is
based on the Intel NetBurst microarchitecture and supports Hyper-Threading
Technology.