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Contents
Embedded AMD-K6™ Processors BIOS Design Guide
23913A/0—November 2000
Preliminary Information
Model 8/[F:8] Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Extended Feature Enable Register (EFER) . . . . . . . . . . . . . . 24
Write Handling Control Register (WHCR) . . . . . . . . . . . . . . . 27
UC/WC Cacheability Control Register (UWCCR) . . . . . . . . . 30
Processor State Observability Register (PSOR) . . . . . . . . . . . 34
Page Flush/Invalidate Register (PFIR) . . . . . . . . . . . . . . . . . . 36
Model 9 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Extended Feature Enable Register (EFER) . . . . . . . . . . . . . . 39
Level-2 Cache Array Access Register (L2AAR) . . . . . . . . . . . 40
Model D Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Processor State Observability Register (PSOR)
(Low-Power Versions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Level-2 Cache Array Access Register (L2AAR) . . . . . . . . . . . 48
Enhanced Power Management Register (EPMR)
(Low-Power Versions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
EPM 16-Byte I/O Block (Low-Power Versions Only) . . . . . . . . 55
Embedded AMD Processor Recognition. . . . . . . . . . . . . . . . . . . . . . . 57
CPUID Instruction Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Testing for the CPUID Instruction . . . . . . . . . . . . . . . . . . . . . . 58
Using CPUID Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Identifying the Processor’s Vendor . . . . . . . . . . . . . . . . . . . . . 60
Testing For Extended Functions . . . . . . . . . . . . . . . . . . . . . . . 61
Determining the Processor Signature . . . . . . . . . . . . . . . . . . . 61
Identifying Supported Features . . . . . . . . . . . . . . . . . . . . . . . . 63
Determining Instruction Set Support. . . . . . . . . . . . . . . . . . . . 64
Detection Algorithm for Determining Instruction Set
Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
AMD Processor Signature (Extended Function). . . . . . . . . . . 66
Displaying the Processor’s Name . . . . . . . . . . . . . . . . . . . . . . . 66
Displaying Cache Information . . . . . . . . . . . . . . . . . . . . . . . . . 67
Determining AMD PowerNow!™ Technology Information . . 67
Sample Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
New AMD-K6™ Processor Instructions. . . . . . . . . . . . . . . . . . . . . . . . 68
Additional Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69