http://eprom.myetang.com/intr/int.htm   : Interrupt Jump Table
http://hdebruijn.soo.dto.tudelft.nl/newpage/interupt/INT.HTM
http://lrs.fmi.uni-passau.de/support/doc/interrupt-57/INT.HTM : Interrupt Jump Table
http://members.tripod.com/~oldboard/assembly/idx_interrupt.html
http://moon.inf.uji.es/docs/interr/ : Interrupts
http://poli.cs.vsb.cz/misc/rbint/ : Ralph Browns List of Interrupt files
http://www.clipx.net/ng/rbrown/index.php : Ralph Browns Interrupt List
http://www.hszk.bme.hu/~kr304/intlist.htm : Ralph Browns Interupt list (3.5 MB)
http://www.htl-steyr.ac.at/~morg/pcinfo/hardware/interrupts/inte1at0.htm
http://www.iro.umontreal.ca/~feeley/cours/ift2240/doc/assembly/interrup.html  

09 : BIOS keyboard handler
10 : BIOS screen services
11 : BIOS Equipment list
13 : BIOS Disk services
14 : BIOS Serial communication (RS-232) services
15 : BIOS System services
16 : BIOS Keyboard services
17 : BIOS Parallel port (printer) services
19 : Bootstrap Loader
1A : BIOS Timer services
20 : DOS Terminate
21 : DOS Functions
25 : DOS Sector Read
26 : DOS Sector Write
27 : DOS TSR
29 : DOS Quick TTL
2F : DOS Multiplex

INT 09: BIOS keyboard handler

> port 60h

> DOS6PT.112

- read 1-byte scancode at port 60h
- check for special combinations
- <ctrl-break> set bit 7 of 40:71 - put 2 0-bytes in keyboard buffer

issue INT 1Bh (some ctrl-break handler)

- <pause> suspend (loop) until any other key - discard the scan code
- <ctrl-alt-del> put 1234h ('warm boot') in reset flag at 40:72, reboot.
- <prtsc> issue INT 5
- <alt-sysreq> issue INT 15h, 85h (do nothing - for terminal emulation)
- if shift/toggle key: set 40:17-18
- else: translate into (Ascii+scan) using 40:17-18
- place byte-pair in keyboard buffer at 40:1E
- may be hooked >INT 21.25: Set Interupt Vector

 

INT 10: BIOS Screen Services

 

INT 11: Equipment List

returns bitflags in AX:

bits	MEGA386SX
0	1	=1 :one or more diskette drives exist (see bits 7,6)
1	0	=1 :math coprocessor installed
3,2	00	old PC & PCjr: RAM on main board: =00:16k, =01:32k, =10:48k, =11:64k newer PCs: use INT 12 for mem info PS/2: bit 2: =1:mouse installed
5,4	10	initial videomode: =00:unknown adapter =01:color txt 40*25 (uses B800) =10:color txt 80*25 (uses B800) =11:mono txt 80*25 (uses B000)
7,6	01	no. of installed diskette drives: (see bit 0) =00:1, =01:2, =10:3, =11:4
8	0	=0: DMA present
11,10,9	010 (=2)	no. of installed RS232 serial ports (binary no.)
12	0	=1: game I/O (joystick controller) installed
13	0	PC & XT: =1:internal modem installed PCjr: =1:serial printer is on
15,14	01 (=1)	no. of printers installed (binary no.)

 

INT 13: BIOS Disk services

uses parameter tables pointed to by INT 1E, INT 41, INT 46

Sector = LogicalSector MOD SectorsPerTrack + 1

Head =(LogicalSector \ SectorsPerTrack) MOD NumberOfHeads

Cylinder = LogicalSector \(SectorsPerTrack*NumberOfHeads)

compare DOS INT 25

 

AH=0: reset drive and controller AL=drive =00: first floppy drive =80: first hard drive	AH=disk status: (hex) = 0: no error = 1: function invalid = 2: sector mark not found = 3: write attempt on write-protected floppy = 4: sector not found = 8: DMA overflow = 9: DMA crossed 64k boundary =10: read error (CRC or ECC) =20: disk controller error =40: track not found on seek =80: time out - drive not responding
AH=1: get disk status	AH=disk status (see above)
AH=2: read disk sectors AL= no.of sectors DH= side (0-1) DL= drive (0-3) CH= track (0-39d) CL= start sector (1-9) ES:BX-> buffer for info	AH=disk status AL=no.of read sectors Cf=0: no error (ES changed)
AH=3: write disk sectors AL,DX,CX,ES,BX as above	as above
AH=4: verify disk sectors as above	as above Cf=1: verify error
AH=5: format disk track ES:BX-> table see JL/HN"maskinkode.."p.130

 

INT 14: BIOS Serial communications (RS-232) services

 

AH=0: Initialize Serial Port AL=initializing parameters bit 7,6,5: Baud: 000= 110 001= 150 010= 300 011= 600 100=1200 101=2400 110=4800 111=8600 4,3: Parity: 00=none 01=odd 11=even 2: Stopbit: 0=1 bit 1=2 bit 1,0: Word Length: 10=7 bit 11=8 bit DX=serial port =0,1: COM1,COM2	AX=Serial Port Status
AH=1: Send Character AL=character DX=serial port	AH bit 7 = 0: no error AL = character -- or -- AH bit 7 = 1: transmission error AL bit 0-6 : status
AH=2: Read Character DX=serial port	AH bit 7 = 0: no error AL = character -- or -- AH bit 7 = 1: transmission error
AH=3: Get Serial Port Status DX=serial port	AH = transmission status code AL = modem status code

 

INT 15: BIOS System services

PC: Cassette/ AT: virtual memory

 

AH=85: SysReq - see INT 9h
AH=86
AH=87: Protected mode Data Move
AH=88: Get Extended Memory Size
AH=C0: >DOS6PT.23	CF set: no success - ignore ES:BX -> configuration table byte 5: bit 2: 1: EBDA is present
AH=C1: >DOS6PT.23	CF set: no success - ignore ES = segment of EBDA

 

INT 16: BIOS Keyboard services

 

AH=0: read (wait for) key AL=0 remove 2 bytes from buffer	AH=scan code AL=ASCII code note: will not read F11,F12 - use AH=10?
AH=0: read (wait for) key AL<>0	AH=extended IBM keycode (?)
AH=1: preview char bytes are not removed	Zf=1: no codes in key buffer Zf=0: codes in buffer: AH=scan code AL=ASCII code
AH=2: report keyboard status bits	AL=bits at 0417h: 0=1: <right shift> pressed 1=1: <left shift> pressed 2=1: <ctrl> pressed 3=1: <alt> pressed 4=1: <scroll lock> on 5=1: <num lock> on 6=1: <caps lock> on 7=1: <Insert> on
AH=10?: reads F11,F12 (see AH=0)

 

INT 17: BIOS Parallel Port (Printer) services

 

AH=0: Write Character AL=character DX=printer no. =0: LPT1 =1: LPT2 =2: LPT3 =3: (LPT4)	AH= printer status: - see port 379h 0=1: time out error 1,2: not used 3=1: I/O error (off line / out of paper) 4=1: selected (on line) =0: off line 5=1: out of paper 6=1: acknowledge - data received, ready for more 7=1: printer not busy (on line) =0: busy (printing) or off line
AH=1: initialize printer DX=printer no.	AH= printer status - see above
AH=2: report printer status DX=printer no.	AH= printer status - see above

 

INT 1A: BIOS time services

clock number is 4 bytes, each count = 1 tick (18.2/sec)
automatically reset at midnight (18.2*60*60 = 65520)

 

AH=0: read clock	CX=hi bits: incremented approx. each hour DX=lo bits: incremented each 55 ms (1/18.2 sec)
AH=1: set clock CX,DX: new value

 

INT 19: Bootstrap Loader

Reads track 0, sector 1 into 0000:7C00 - then jumps to this address

 

INT 20: DOS Terminate

CS must point to PSP - used in .COM programs - same as INT 21,0
restore INT 22,23,24 vectors from old values stored in PSP.
does not close open files.

 

INT 21: DOS Services

 

INT 25: DOS sector read

- using logical drives (remapped by ASSIGN)
- using Logical Sectors 0..
LogicalSector = BIOSSector - 1 +
SectorsPerTrack*(Head + NumberOfHeads*Cylinder)
compare BIOS INT 13,2

 

AL= disk drive (A:0, B:1, C:2,..) CX= no. of sectors to read DX= starting sector nr. DS:BX->buffer(DTA)

NB - after return: old flag-register on stack - remove with ADD SP,2 or POP (>PCPB.249) CF=0/1: no error/error AL=error codes based on DOS INT 24 codes =00: write-protect error =01: unknown unit, invalid drive number =02: drive not ready =04: CRC error, parity error =06: seek error =07: unknown media =08: sector not found =0A: write error =0B: read error =0C: general, nonspecific error =0F: invalid disk change AH=error codes based on BIOS INT 13 codes =01: bad command =02: bad address (sector ID) mark =03: write-protect error =04: sector error, sector not on disk =08: DirectMemoryAccess error =10: CRC error, parity error =20: disk drive controller error =40: seek error =80: time-out (no response from drive)

 

INT 26: DOS sector write

 

as INT 25 CX= no. of sectors to write

NB - after return: old flag-register on stack - remove with ADD SP,2 or POP (>PCPB.249) as INT 25

 

INT 27: DOS TSR

max 64K resident (DX)
recommended alternative: INT 21,31

 

CS->PSP CS:DX=offset EndOfResidentPart (first non-resident byte)

restore INT 22,23,24 vectors from old values stored in PSP.

 

INT 29: DOS Quick TTL

(undocumented) - Somerson DOSPT.476

 

AL= char

moves cursor

 

INT 2F: DOS Multiplex

used to communicate with memory resident programs (TSR)
used by PRINT spooler - ID (in AH) 1
>PCProgBible.250..
>PC'ere under lup s.130..

 

AH=01: PRINT AL=00: Get Installed Status	AL=0: spooler not installed - ok to install =1: spooler not installed - not ok to install =FF: spooler installed
AH=01: PRINT AL=01: Submit (add) File to Print DS:DX->5-byte area: 1 : niveau code (?) 2-5: seg:offs pointer to ASCIIZ-path\filename	CF=0: ok CF=1: error: AX=error code
AH=01: PRINT AL=02: Remove File from Queue DS:DX->ASCIIZ-path\filename	CF=0: ok CF=1: error: AX=error code
AH=01: PRINT AL=03: Cancel all Files in Queue	CF=0: ok CF=1: error: AX=error code
AH=01: PRINT AL=04: Hold (show) Queue	CF=0: ok: DS:SI->Queue (list of filenames) CF=1: error: AX=error code DX=number of errors (?)
AH=01: PRINT AL=05: Release Queue (functions 0-3 also release queue)	CF=0: ok CF=1: error: AX=error code
AH=01: PRINT AL=06: Get Printer's Header