F000:F065h
F000:F0A4h
F000:F841h
F000:F84Dh
F000:F859h
F000:FA6Eh
F000:FE6Eh
F000:FEA5h
F000:FF53h
F000:FF54h
F000:FFF0h
F000:FFF5h
F000:FFFEh
SurePOS 500
Compatibility for Video interrupt
MDA and CGA Video Parameter Table Int 1Dh Int 12h Entry Point
Int 11h Entry Point
Int 15h Entry Point
Low 128 character of graphic video font Int 1Ah Entry Point
Int 08h Entry Point Dummy Interrupt Handler
Int 05h Print Screen Entry Point
8 character ROM Date in ASCII “MM/DD/YY” System Model (FCh) (outdated – use SMBIOS)
3.6BDA Memory Addresses
The BIOS Data Area (BDA) starts at 40:0 and should be populated as follows.
Start | Length in | Description | Interrupt | Comments | |
Location | bytes | Using It | |||
|
| ||||
00h | 2 | COM1 base address | 14h | motherboard UART1 I/O address | |
02h | 2 | COM2 base address | 14h | motherboard UART2 I/O address | |
04h | 2 | COM3 base address | 14h | motherboard UART5 I/O address | |
06h | 2 | COM4 base address | 14h | motherboard UART4 I/O address | |
08h | 2 | LPT1 base address | 17h | Should be 0000h | |
0Ah | 2 | LPT2 base address | 17h | Should be 0000h | |
0Ch | 2 | LPT3 base address | 17h | Should be 0000h | |
0Eh | 2 | EBDA segment |
|
| |
10h | 2 | Installed hardware | 11h |
| |
12h | 1 | Reserved |
|
| |
13h | 2 | Base memory size | 12h |
| |
15h | 2 | Reserved |
|
| |
17h | 1 | Keyboard control 1 | 16h |
| |
18h | 1 | Keyboard control 2 | 16h |
| |
19h | 1 | Work area for ALT key | 16h |
| |
1Ah | 2 | 16h |
| ||
1Ch | 2 | 16h |
| ||
1Eh | 32 | Keyboard Buffer | 16h |
| |
3Eh | 1 | Floppy recalibrate status | 13h |
| |
3Fh | 1 | Floppy motor status | 13h |
| |
40h | 1 | Floppy motor timeout | 13h |
| |
41h | 1 | Floppy operation status | 13h |
| |
42h | 7 | Floppy controller status | 13h |
| |
49h | 30 | Video info | 10h |
| |
67h | 4 | POST callback address |
|
| |
6Bh | 1 | Last Unexpected |
|
| |
interrupt |
|
| |||
|
|
|
|
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