Compatibility Issues

Bios Special Compatible Subroutine

The following code fragment must be present at the address indicated for compatibility with the Industry Standard.

F000:E00D 20 49 42        AND [BX+DI+42],CL    ;db ' ', 'I', 'B', 'M' 
F000:E010 4D              DEC BP
F000:E011 C3              RET

Compatibility Addresses

The table below shows the compatible entry points and data table addresses which the 100LX/200LX BIOS system supports.

Int    ROM Entry   Type    Function
------------------------------------------------------------------------------------------
--     F000:E05B   code    Reset
02     F000:E2C3   code    Nonmaskable Interrupt
19     F000:E6F2   code    Boot
--     F000:E729   data    Baud rate divisor table
14     F000:E739   code    Serial 
16     F000:E82E   code    Keyboard 
09     F000:E987   code    Int 09h (Kbd ISR)
13     F000:EC59   code    Int 13h (Disk Services)
0E     F000:EF57   code    Disk ISR (Not used in 100LX/200LX)
--     F000:EFC7   data    Disk parameter table (Not used in 100LX/200LX)
17     F000:EFD2   code    Int 17h (Printer Services)
10     F000:F065   code    Int 10h (Video Services)
1D     F000:F0A4   data    Video parameter table
12     F000:F841   code    Int 12h (Memory Size)
11     F000:F84D   code    Int 11h (Equipment Check)
15     F000:F859   code    Int 15h (System Services)
--     F000:FA6E   data    8x8 Character table (lower 128 chars only)
1A     F000:FE6E   code    Int 1Ah (Time and Date Services)
08     F000:FEA5   code    Int 08h (Timer0 ISR)
--     F000:FEF3   data    Interrupt Vector Table
--     F000:FF23   data    Unexpected Interrupt Handler (handles interrupts not 
                           specifically handled by the BIOS.
--     F000:FF53   code    Dummy IRET
05     F000:FF54   code    Int 05h (Print Screen)
--     F000:FFF0   code    Hardware reset point
--     F000:FFF5   data    BIOS date stamp 
--     F000:FFFE   data    Hardware ID byte
Notes: