Intel® Architecture Instruction Set Extensions Programming Reference

APPLICATION PROGRAMMING MODEL
Table 2-23. Information Returned by CPUID Instruction
Initial EAX
Value Information Provided about the Processor
Basic CPUID Information
0H EAX
EBX
ECX
EDX
01H EAX
EBX
ECX
EDX
02H EAX
EBX
ECX
EDX
Maximum Input Value for Basic CPUID Information (see Table 2-24)
“Genu”
“ntel”
“ineI”
Version Information: Type, Family, Model, and Stepping ID (see Figure 2-2)
Bits 7-0: Brand Index
Bits 15-8: CLFLUSH line size (Value ∗ 8 = cache line size in bytes)
Bits 23-16: Maximum number of addressable IDs for logical processors in this physical package*.
Bits 31-24: Initial APIC ID
Feature Information (see Figure 2-3 and Table 2-26)
Feature Information (see Figure 2-4 and Table 2-27)
NOTES:
* The nearest power-of-2 integer that is not smaller than EBX[23:16] is the maximum number of
unique initial APIC IDs reserved for addressing different logical processors in a physical package.
Cache and TLB Information (see Table 2-28)
Cache and TLB Information
Cache and TLB Information
Cache and TLB Information
03H 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.)
NOTES:
Processor serial number (PSN) is not supported in the Pentium 4 processor or later. On all models,
use the PSN flag (returned using CPUID) to check for PSN support before accessing the feature.
See AP-485, Intel Processor Identification and the CPUID Instruction (Order Number 241618) for
more information on PSN.
04H
CPUID leaves > 3 < 80000000 are visible only when IA32_MISC_ENABLES.BOOT_NT4[bit 22] = 0 (default).
Deterministic Cache Parameters Leaf
NOTES:
Leaf 04H output depends on the initial value in ECX.
See also: “INPUT EAX = 4: Returns Deterministic Cache Parameters for each level on page 2-44.
EAX Bits 4-0: Cache Type Field
0 = Null - No more caches
1 = Data Cache
2 = Instruction Cache
3 = Unified Cache
4-31 = Reserved
2-28 Ref. # 319433-014