Amd Processor Signature (Extended Function); Displaying The Processor's Name; Figure 30. Contents Of Eax Register Returned By Extended Function 8000_0001H - AMD -K6-2/450 - MHz Processor Application Note

Embedded AMD-K6™ Processors BIOS Design Guide
3DNow! Extensions
Test
AMD Multimedia
Instruction
Extensions Test

AMD Processor Signature (Extended Function)

31
Reserved
Generation/Family
Model
Stepping

Figure 30. Contents of EAX Register Returned by Extended Function 8000_0001h

Displaying the Processor's Name

66
Preliminary Information
10. If bit 30 of the extended feature flags is set to 1, the
additions to the 3DNow! instruction set are supported.
11. If bit 22 of the extended feature flags is set to 1, the new
multimedia enhancement instructions that augment the
MMX instruction set are supported.
Extended function 8000_0001h returns the embedded AMD
processor signature. The signature is returned in the EAX
register and provides generation, model, and stepping
information for AMD processors. Figure 30 shows the contents
returned in the EAX register.
11–8
7–4
3–0
Extended functions 8000_0002h, 8000_0003h, and 8000_0004h
return an ASCII string containing the name of the processor
(also called the boot string or name string). These functions
eliminate the need for software to search for the processor
name in a lookup table, a process requiring a large block of
memory and frequent updates. Instead, software can simply
call these three functions to obtain the name string (48 ASCII
characters in little-endian format) and display it on the screen.
Although the name string can be up to 48 characters in length,
shorter names have the remaining byte locations filled with the
ASCII NULL character (00h). To simplify the display routines
and avoid using screen space, software only needs to display
characters until a NULL character is detected.
23913A/0—November 2000
12 11 8 7
Embedded AMD Processor Recognition
4 3 0