IBM 500 Manuel D’Utilisation

Page 23 of 63 

•  Memory Location 40:96h 

This word contains the extended keyboard status. 

•  Memory Location 40:72h 

This word contains the soft reset flag. 

•  Int 10h – Video 

This interrupt is supported by the video ROM. 
Int 11h - Equipment Determination 

Returns the data at memory location 40:10h. 

•  Memory Location 40:10h 

This word contains the equipment list. 

•  Int 12h - Base Memory Size 

Returns the value at memory location 40:13h. 

•  Memory Location 40:13h 

This word contains the amount of memory up to 640 KB.  This count will often be less than 640 KB due to NIC 
ROM bootloaders. 

•  Int 13h - HDD and Floppy Diskette Services 

•  Int 14h - Serial Communication Services 

•  Int 15h - System Services 

Sub functions are those defined by the IBM Personal System/2 and Personal Computer BIOS Interface Technical 
Reference manual.  Additional sub function support is OEM dependent. 

•  Int 16h - Keyboard Services 

•  Int 1Ah - System-Timer Services, PCI BIOS 

•  Int 1Bh – CTRL+Break Handler 

•  Int 1Ch - Periodic Timer Interrupt 

•  Int 1Dh - Video Parameter Table 

Set by the video BIOS 

•  Int 1Eh - Floppy Diskette Drive Parameters 

Points to an 11-byte data structure 

•  Int 1Fh - Video Graphics Characters 

Set by the video BIOS 

•  Int 23h - CTRL+C, CTRL+Break Handler 

•  Int 41h - HDD C: Drive Parameters 

Points to a 16-byte data structure for drive C: 

•  Int 46h - HDD D: Drive Parameters 

Points to a 16-byte data structure for drive D: 

The fixed entry points in F000:xxxx must be supported for traditional reasons.  The table below lists the fixed BIOS 
entry points. 

F000:E05Bh 

POST Entry Point 

F000:E2C3h 

NMI Entry Point 

F000:E6F2h 

Int 19h Entry Point 

F000:E6F5h 

Configuration Data Table 

F000:E729h 

Baud Rate Generator Table 

F000:E739h 

Int 14h Entry Point 

F000:E82Eh 

Int 16h Entry Point 

F000:E987h 

Int 09h Entry Point 

F000:EC59h 

Int 13h Floppy Entry Point 

F000:EF57h 

Int 0Eh Entry Point 

F000:EFC7h 

Floppy Disk Controller Parameter Table 

F000:EFD2h 

Compatibility for printer Int 17h