Initial EAX
Value Information Provided about the Processor
BASIC CPUID Information
0H EAX Maximum Input Value for Basic CPUID Information
EBX "Genu"
ECX "ntel"
EDX "inel"
1H EAX Version Information (Type, Family, Model, and Stepping ID)
EBX Bits 7-0: Brand Index
Bits 15-8: CLFLUSH line size. (Value returned ∗ 8 = cache line size)
Bits 23-16: Reserved.
Bits 31-24: Processor local APIC physical ID
ECX Reserved
EDX Feature Information
2H EAX Cache and TLB Information
EBX Cache and TLB Information
ECX Cache and TLB Information
EDX Cache and TLB Information
3H EAX Reserved
EBX Reserved
ECX Bits 00-31 of 96 bit processor serial number. (Available in
Pentium III processor only; otherwise,
the value in this register is reserved.)
EDX Bits 32-63 of 96 bit processor serial number. (Available in
Pentium III processor only; otherwise,
the value in this register is reserved.)
Extended Function CPUID Information
80000000H EAX Maximum Input Value for Extended Function CPUID Information
EBX Reserved
ECX Reserved
EDX Reserved
80000001H EAX Extended Processor Signature and Extended Feature Bits.
EBX Reserved
ECX Reserved
EDX Reserved
80000002H EAX Processor Brand String
EBX Processor Brand String Continued
ECX Processor Brand String Continued
EDX Processor Brand String Continued
80000003H EAX Processor Brand String Continued
EBX Processor Brand String Continued
ECX Processor Brand String Continued
EDX Processor Brand String Continued
80000004H EAX Processor Brand String Continued
EBX Processor Brand String Continued
ECX Processor Brand String Continued
EDX Processor Brand String Continued
当通过向EAX寄存器置入0H获取Vendor Information时应顺序读取EAX、EDX和ECX的数据,如:
EBX ← 756e6547h (* "Genu", with G in the low nibble of BL *)
EDX ← 49656e69h (* "ineI", with i in the low nibble of DL *)
ECX ← 6c65746eh (* "ntel", with n in the low nibble of CL *)
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 1H Not Implemented
Pentium Pro and Pentium II
Processors, Intel Celeron™
Processors 2H Not Implemented
Pentium III Processors 3H Not Implemented
Pentium 4 Processors 2H 80000004H
Intel Xeon Processors 2H 80000004H
当EAX初始值为1时,返回CPU版本信息到EAX寄存器,版本信息分布如下:
处理器类型对应表如下:
Type Encoding
Original OEM Processor 00B
Intel OverDrive® Processor 01B
Dual processor* 10B
Intel reserved. 11B