G1-266B-85-1.8
| Model | G1-266B-85-1.8 |
| Description | Processor Series Low Power Integrated x86 Solution |
| PDF file | Total 247 pages (File size: 4M) |
| Chip Manufacturer | NSC |
Geode™ GX1 Processor Series
Instruction Set
(Continued)
8.2.2 Extended CPUID Levels
Testing for extended CPUID instruction support can be
accomplished by executing a CPUID instruction with the
EAX register initialized to 80000000h. If a value greater
than or equal to 80000000h is returned to the EAX regis-
ter by the CPUID instruction, the processor supports
extended CPUID levels.
8.2.2.1 CPUID Instruction with EAX = 8000 0000h
Extended function 80000000h (EAX = 80000000h) of the
CPUID instruction returns the maximum extended CPUID
levels supported by the current processor in EAX (Table 8-
reserved.
Table 8-22. EAX, EBX, ECX CPUID Data
Returned when EAX = 80000001h
Register
EAX[3:0]
EAX[7:4]
EAX[11:8]
EAX[15:12]
EAX[31:16]
EBX
ECX
Returned
Contents
xx
4
5
0
-
-
-
Description
Stepping ID
Model
Family
Processor Type
Reserved
Reserved
Reserved
Table 8-21. Maximum Extended CPUID Level
Register
EAX
EBX
ECX
EDX
Returned
Contents
8000 0005h
-
-
-
Description
Maximum Extended CPUID
Level (six levels)
Reserved
Reserved
Reserved
Table 8-23. EDX CPUID Data Returned
when EAX = 80000001h
Returned
EDX
EDX[0]
EDX[1]
EDX[2]
EDX[3]
Contents
1
0
0
0
1
1
1
Feature Flag
FPU On-Chip
Virtual Mode Extension
Debugging Extension
Page Size Extension
(4 MB)
Time Stamp Counter
Model-Specific Registers
(via RDMSR / WRMSR
Instructions)
Reserved
Machine Check Exception
CMPXCHG8B Instruction
Reserved
Reserved
SYSCALL / SYSRET
Instruction
Reserved
Page Global Enable
Reserved
Integer Conditional Move
Instruction
FPU Conditional Move
Instruction
Reserved
MMX
6x86MX Multimedia
Extensions
CR4
Bit
-
-
-
-
2
-
8.2.2.2 CPUID Instruction with EAX = 80000001h
Extended function 80000001h (EAX = 80000001h) of the
CPUID instruction returns the processor type, family,
model, and stepping information of the current processor
in EAX. The EBX and ECX registers are reserved.
The extended feature flags supported are returned in the
EDX register as shown in Table 8-23. Each flag refers to a
specific feature and indicates if that feature is present on
the processor. Some of these features have protection
control in CR4. Before using any of these features on the
processor, the software should check the corresponding
feature flag.
EDX[4]
EDX[5]
EDX[6]
EDX[7]
EDX[8]
EDX[9]
EDX[10]
EDX[11]
EDX[12]
EDX[13]
EDX[14]
EDX[15]
EDX[16]
EDX[22:17]
EDX[23]
EDX[24]
1.
0
0
1
0
0
0
0
0
0
1
0
0
1
1
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0 = Not supported
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