IBM 500 Manuel D’Utilisation
SurePOS 500 4846-XX5 Technical Reference
Page 24 of 63
F000:F065h
Compatibility for Video interrupt
F000:F0A4h
MDA and CGA Video Parameter Table Int 1Dh
F000:F841h
Int 12h Entry Point
F000:F84Dh
Int 11h Entry Point
F000:F859h
Int 15h Entry Point
F000:FA6Eh
Low 128 character of graphic video font
F000:FE6Eh
Int 1Ah Entry Point
F000:FEA5h
Int 08h Entry Point
F000:FF53h
Dummy Interrupt Handler
F000:FF54h
Int 05h Print Screen Entry Point
F000:FFF0h
Power-On Entry Point
F000:FFF5h
8 character ROM Date in ASCII “MM/DD/YY”
F000:FFFEh
System Model (FCh) (outdated – use SMBIOS)
3.6 BDA Memory Addresses
The BIOS Data Area (BDA) starts at 40:0 and should be populated as follows.
Start
Location
Location
Length in
bytes
bytes
Description
Interrupt
Using It
Using It
Comments
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
Keyboard-buffer Head
16h
1Ch
2
Keyboard-buffer Tail
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
interrupt