INT 11, INT 12, INT 16, INT 19 8086 Microprocessor by Ravinder Nath Rajotiya - April 19, 20210 Share on Facebook Share Send email Mail Print Print INT 11h – get BIOS equipment list. INT 11h D15-14 D13 D12 D11-9 D8 D7-6 D5-4 D3 D2 D1 D0 Get BIOS equipment list. No. of // device Res Game port yes/ no No. of serial device Res. No. of FDD-1 Initial vedio mode res PS/2 mouse installed Math uP installed Set if booted from FDD Return Bios list word in AX; details given here for All bits D15-0 from memory 0040:0010h 00 – 1 01 – 2 10 – 3 11 – 4 0 no 1yes 000 001 010 011 100 101 110 111 00 -1 01 -2 10- 3 11-4 00 EGA/ VGA/PGA 01 – 40×25 CGA color 10 – 80×25 CGA color 11 – 80×25 mono txt 1 yes 0 no 1-enabled 2- Diabled INT 12h – Get Memory Size. INT 12h Service no. NIL Returns Description Example Get memory Size. AX = kilobytes of contiguous memory starting at absolute address 00000h, this call returns the contents of the word at 0040h:0013h INT 16h / AH = 00h – get keystroke from keyboard (no echo). INT 16h Service no. 00h Returns Description Example Get keystroke from keyboard (no echo). AH = BIOS scan code. AL = ASCII Character. (if a keystroke is present, it is removed from the keyboard buffer). INT 16h / AH = 01h – Check for keystroke in the keyboard buffer. INT 16h Service no. 01h Returns Description Example Check for keystroke in the keyboard buffer. ZF = 1 if keystroke is not available. ZF = 0 if keystroke available. AH = BIOS scan code. AL = ASCII Character. (if a keystroke is present, it is not removed from the keyboard buffer). INT 19h – system reboot. Usually, the BIOS will try to read sector 1, head 0, track 0 from drive A: to 0000h:7C00h. The emulator just stops the execution, to boot from floppy drive select from the menu: ‘virtuAL drive’ -> ‘boot from floppy’ INT 1Ah / AH = 00h – get system time. INT 1Ah Service no. 00h Returns Description Example Get system time. CX:DX = number of Clock ticks SInce midnight. AL = midnight counter, advanced each time midnight passes. notes: there are approximately 18.20648 Clock ticks per second, and 1800B0h per 24 hours. AL is not set by the emulator INT 20h – exit to operating system. Share on Facebook Share Send email Mail Print Print