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Vol. 3 9-5
PROCESSOR MANAGEMENT AND INITIALIZATION
9.1.3 Model and Stepping Information
Following a hardware reset, the EDX register contains component identification and
revision information (see
Figure 9-2). For example, the model, family, and processor
type returned for the first processor in the Intel Pentium 4 family is as follows: model
(0000B), family (1111B), and processor type (00B).
The stepping ID field contains a unique identifier for the processor’s stepping ID or
revision level. The extended family and extended model fields were added to the
IA-32 architecture in the Pentium 4 processors.
Figure 9-1. Contents of CR0 Register after Reset
Figure 9-2. Version Information in the EDX Register after Reset
External x87 FPU error reporting: 0
(Not used): 1
No task switch: 0
x87 FPU instructions not trapped: 0
WAIT/FWAIT instructions not trapped: 0
Real-address mode: 0
31
19 16
15
0
P
E
123456
1718
282930
M
P
E
M
1
N
E
T
S
P
G
C
D
N
W
W
P
A
M
Paging disabled: 0
Alignment check disabled: 0
Caching disabled: 1
Not write-through disabled: 1
Write-protect disabled: 0
Reserved
Reserved
31 12 11 8 7 4 3 0
EDX
Family (1111B for the Pentium 4 Processor Family)
Model (Beginning with 0000B)
1314
Processor Type
Model
Family
Stepping
ID
15
Model
Extended
Extended
Family
1619202324
Reserved