Instruction Set (Continued)
9.2.2.3 CPUID Instruction with
9.2.2.4 CPUID Instruction with
EAX = 80000002h, 80000003h, 80000004h
EAX = 80000005h
Extended functions 80000002h through 80000004h (EAX
= 80000002h, EAX = 80000003h, EAX = 80000004h) of
the CPUID instruction return an ASCII string containing
the name of the current processor. These functions elimi-
nate the need to look up the processor name in a lookup
table. Software can simply call these functions to obtain
the name of the processor. The string may be 48 ASCII
characters long, and is returned in little endian format. If
the name is shorter than 48 characters long, the remain-
ing bytes will be filled with ASCII NUL character (00h).
Extended function 80000005h (EAX = 80000005h) of the
CPUID instruction returns information about the TLB and
L1 cache to be looked up in a lookup table. Refer to Table
9-25.
Table 9-25. Standard CPUID with
EAX = 80000005h
Returned
Register
Contents
Description
Reserved
EAX
EBX
--
Table 9-24. Official CPU Name
xx xx 70 xxh TLB is 32 Entry, 4-way set
associative, and has 4 KByte
Pages
80000002h
80000003h
80000004h
EAX CPUName EAX CPU Name EAX CPU Name
EBX
xx xx xx 01h The CPUID instruction needs
to be executed only once with
an input value of 02h to retrieve
complete information about the
cache and TLB
1
5
9
EBX CPUName EBX CPU Name EBX CPU Name
10
ECX CPUName ECX CPU Name ECX CPU Name
11
EDX CPUName EDX CPU Name EDX CPU Name
12
2
6
ECX
EDX
xx xx xx 80h L1 cache is 16 KBytes, 4-way
set associated, and has 16
bytes per line.
3
7
4
8
--
Reserved
Revision 3.1
211
www.national.com
NSC [ National Semiconductor ]
