4 BIOS overview
order in which the POST tests are performed
43 | To enable interrupts for diagnostics mode. | ||
|
|
|
|
44 | To initialize data to check memory wrap around at 0:0. | ||
|
|
|
|
45 | Data initialized. Going to check for memory wrap around at 0:0 and finding the total system | ||
|
| memory size. | |
|
|
|
|
46 | Memory wrap around test done. Memory size calculation over. About to go for writing patterns to | ||
|
| test memory. | |
|
|
|
|
47 | Pattern to be tested written in extended memory. Going to write patterns in base 640k memory. | ||
|
|
|
|
48 | Patterns written in base memory. Going to findout amount of memory below 1M memory. | ||
|
|
|
|
49 | Amount of memory below 1M found and verified. Going to findout amount of memory above 1M | ||
|
| memory. | |
|
|
|
|
| 4B | Amount of memory above 1M found and verified. Check for soft reset and going to clear memory | |
|
| below 1M for soft reset. (If power on, go to check point# 4Eh). | |
|
|
|
|
| 4C | Memory below 1M cleared.(SOFT RESET) Going to clear memory above 1M. | |
|
|
|
|
| 4D | Memory above 1M cleared.(SOFT RESET) Going to save the memory size. (Goto check point# 52h). | |
|
|
|
|
| 4E | Memory test started.(NOT SOFT RESET) About to display the first 64k memory size. | |
|
|
|
|
| 4F | Memory size display started. This will be updated during memory test. Going for sequential and | |
|
| random memory test. | |
|
|
|
|
50 | Memory testing/initialization below 1M complete. Going to adjust displayed memory size for | ||
|
| relocation/ shadow. | |
|
|
|
|
51 | Memory size display adjusted due to relocation/ shadow. Memory test above 1M to follow. | ||
|
|
|
|
52 | Memory testing/initialization above 1M complete. Going to save memory size information. | ||
|
|
|
|
53 | Memory size information is saved. CPU registers are saved. Going to enter in real mode. | ||
|
|
|
|
54 | Shutdown successful, CPU in real mode. Going to disable gate A20 line and disable parity/NMI. | ||
|
|
|
|
57 | A20 address line, parity/NMI disable successful. Going to adjust memory size depending on | ||
|
| relocation/shadow. | |
|
|
|
|
58 | Memory size adjusted for relocation/shadow. Going to clear Hit <DEL> message. Going to clear | ||
|
| Hit <DEL> message. | |
|
|
|
|
59 | Hit <DEL> message cleared. <WAIT...> message displayed. About to start DMA and | ||
|
| interrupt controller test. | |
|
|
|
|
60 | DMA page register test passed. To do DMA#1 base register test. | ||
|
|
|
|
62 | DMA#1 base register test passed. To do DMA#2 base register test. | ||
|
|
|
|
65 | DMA#2 base register test passed. To program DMA unit 1 and 2. | ||
|
|
|
|
66 | DMA unit 1 and 2 programming over. To initialize 8259 interrupt controller. | ||
|
|
|
|
| 7F | Extended NMI sources enabling is in progress. | |
|
|
|
|
|
|
|
|
41