INT 11, INT 12, INT 16, INT 19


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.

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