Intel® Architecture Instruction Set Extensions Programming Reference

INPUT EAX = 80000000H: Returns CPUID’s Highest Value for Extended Processor Information
APPLICATION PROGRAMMING MODEL
When CPUID executes with EAX set to 0, the processor returns the highest value the processor recognizes for
returning extended processor information. The value is returned in the EAX register (see Table 2-24) and is
processor specific.
Table 2-24. Highest CPUID Source Operand for Intel 64 and IA-32 Processors
Intel 64 or IA-32 Processors
Basic Information
Highest Value in EAX
Extended Function Information
Earlier Intel486 Processors CPUID Not Implemented CPUID Not Implemented
Later Intel486 Processors and Pentium
Processors
01H Not Implemented
Pentium Pro and Pentium II Processors,
Intel ® Celeron ® Processors
02H Not Implemented
Pentium III Processors 03H Not Implemented
Pentium 4 Processors 02H 80000004H
Intel Xeon Processors 02H 80000004H
Pentium M Processor 02H 80000004H
Pentium 4 Processor supporting Hyper-
Threading Technology
05H 80000008H
Pentium D Processor (8xx) 05H 80000008H
Pentium D Processor (9xx) 06H 80000008H
Intel Core Duo Processor 0AH 80000008H
Intel Core 2 Duo Processor 0AH 80000008H
Intel Xeon Processor 3000, 5100, 5300
Series
0AH 80000008H
Intel Xeon Processor 3000, 5100, 5200,
5300, 5400 Series
0AH 80000008H
Intel Core 2 Duo Processor 8000 Series 0DH 80000008H
Intel Xeon Processor 5200, 5400 Series 0AH 80000008H
IA32_BIOS_SIGN_ID Returns Microcode Update Signature
For processors that support the microcode update facility, the IA32_BIOS_SIGN_ID MSR is loaded with the update
signature whenever CPUID executes. The signature is returned in the upper DWORD. For details, see Chapter 10 in
the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A.
INPUT EAX = 1: Returns Model, Family, Stepping Information
When CPUID executes with EAX set to 1, version information is returned in EAX (see Figure 2-2). For example:
model, family, and processor type for the Intel Xeon processor 5100 series is as follows:
• Model — 1111B
• Family — 0101B
• Processor Type — 00B
See Table 2-25 for available processor type values. Stepping IDs are provided as needed.
Ref. # 319433-014 2-35