Filter
Top Products
Vol. 2A 3-169
INSTRUCTION SET REFERENCE, A-M
CPUID—CPU Identification
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 9 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 3-5). For example: model, family, and processor type for the Intel Xeon
processor 5100 series is as follows:
• Model — 1111B
• Family — 0101B
• Processor Type — 00B
Table 3-13. Highest CPUID Source Operand for Intel 64 and IA-32 Processors
Intel 64 or IA-32 Processors
Highest Value in EAX
Basic Information 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