Appendix B: BIOS POST Codes
B-3
POST (hex) Defi nition
2Fh Reserved
30h Reserved
31h Reserved
32h Reserved
33h Reset keyboard except Winbond 977 series Super I/O chips
34h Reserved
35h Reserved
36h Reserved
37h Reserved
38h Reserved
39h Reserved
3Ah Reserved
3Bh Reserved
3Ch Test 8254
3Dh Reserved
3Eh Test 8259 interrupt mask bits for channel 1
3Fh Reserved
40h Test 8259 interrupt mask bits for channel 2
41h Reserved
42h Reserved
43h Test 8259 functionality
44h Reserved
45h Reserved
46h Reserved
47h Initialize EISA slot
48h Reserved
49h 1. Calculate total memory by testing the last double word of each 64K page.
2. Program writes allocation for AMDK5 CPU.
4Ah 1. Initialize multi-language
2. Put information on screen display, including Award title, CPU type, CPU speed, etc.
4Bh Reserved
4Ch Reserved
4Dh Reserved
4Eh 1. Program MTRR of M1 CPU.
2. Initialize L2 cache for P6 class CPU & program CPU with proper cacheable range.
3. Initialize the APIC for P6 class CPU.
4. On MP platform, adjust the cacheable range to smaller one in case the cacheable ranges
between each CPU are not identical.
4Fh Reserved
50h Initialize USB
51h Reserved