Intel® Architecture Instruction Set Extensions Programming Reference

APPLICATION PROGRAMMING MODEL
Table 2-23. Information Returned by CPUID Instruction(Continued)
Initial EAX
Value Information Provided about the Processor
80000007H EAX
EBX
ECX
EDX
NOTES:
* L2 associativity field encodings:
00H - Disabled
01H - Direct mapped
02H - 2-way
04H - 4-way
06H - 8-way
08H - 16-way
0FH - Fully associative
Reserved = 0
Reserved = 0
Reserved = 0
Reserved = 0
80000008H EAX Virtual/Physical Address size
Bits 7-0: #Physical Address Bits*
Bits 15-8: #Virtual Address Bits
Bits 31-16: Reserved = 0
EBX
ECX
EDX
Reserved = 0
Reserved = 0
Reserved = 0
NOTES:
* If CPUID.80000008H:EAX[7:0] is supported, the maximum physical address number supported
should come from this field.
INPUT EAX = 0: Returns CPUID’s Highest Value for Basic Processor Information and the Vendor Identification String
When CPUID executes with EAX set to 0, the processor returns the highest value the CPUID recognizes for
returning basic processor information. The value is returned in the EAX register (see Table 2-24) and is processor
specific.
A vendor identification string is also returned in EBX, EDX, and ECX. For Intel processors, the string is “GenuineIntel”
and is expressed:
EBX ← 756e6547h (* "Genu", with G in the low 4 bits of BL *)
EDX ← 49656e69h (* "ineI", with i in the low 4 bits of DL *)
ECX ← 6c65746eh (* "ntel", with n in the low 4 bits of CL *)
2-34 Ref. # 319433-014