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Vol. 2A 3-183
INSTRUCTION SET REFERENCE, A-M
CPUID—CPU Identification
Table 3-18 shows the brand string that is returned by the first processor in the
Pentium 4 processor family.
Extracting the Maximum Processor Frequency from Brand Strings
Figure 3-9 provides an algorithm which software can use to extract the maximum
processor operating frequency from the processor brand string.
NOTE
When a frequency is given in a brand string, it is the maximum
qualified frequency of the processor, not the frequency at which the
processor is currently running.
Table 3-18. Processor Brand String Returned with Pentium 4 Processor
EAX Input Value Return Values ASCII Equivalent
80000002H EAX = 20202020H
EBX = 20202020H
ECX = 20202020H
EDX = 6E492020H
“ ”
“”
“”
“nI ”
80000003H EAX = 286C6574H
EBX = 50202952H
ECX = 69746E65H
EDX = 52286D75H
“(let”
“P )R”
“itne”
“R(mu”
80000004H EAX = 20342029H
EBX = 20555043H
ECX = 30303531H
EDX = 007A484DH
“ 4 )”
“ UPC”
“0051”
“\0zHM”