| Interrupt |
Description |
| INT 00h |
CPU: Executed after an attempt to divide by zero or when the quotient does not fit in the destination |
| INT 01h |
CPU: Executed after every instruction while the trace flag is set |
| INT 02h |
CPU: NMI, used e.g. by POST for memory errors |
| INT 03h |
CPU: The lowest non-reserved interrupt, it is used exclusively for debugging, and the INT 03 handler is always implemented by a debugging program |
| INT 04h |
CPU: Numeric Overflow. Usually caused by the INTO instruction when the overflow flag is set. |
| INT 05h |
Executed when Shift-PrintScreen is pressed, as well as when the BOUND instruction detects a bound failure. |
| INT 06h |
CPU: Called when the Undefined Opcode (invalid instruction) exception occurs. Usually installed by the operating system. |
| INT 07h |
CPU: Called when an attempt was made to execute a floating-point instruction and no numeric coprocessor was available. |
| INT 08h |
IRQ0: Implemented by the system timing component; called 18.2 times per second (once every 55 ms) by the PIC |
| INT 09h |
IRQ1: Called after every key press and release (as well as during the time when a key is being held) |
| INT 0Bh |
IRQ3: Called by serial ports 2 and 4 (COM2/4) when in need of attention |
| INT 0Ch |
IRQ4: Called by serial ports 1 and 3 (COM1/3) when in need of attention |
| INT 0Dh |
IRQ5: Called by hard disk controller (PC/XT) or 2nd parallel port LPT2 (AT) when in need of attention |
| INT 0Eh |
IRQ6: Called by floppy disk controller when in need of attention |
| INT 0Fh |
IRQ7: Called by 1st parallel port LPT1 (printer) when in need of attention |
| INT 10h |
Video Services - installed by the BIOS or operating system; called by software programs
| AH=00h |
Set Video Mode |
| AH=01h |
Set Cursor Shape |
| AH=02h |
Set Cursor Position |
| AH=03h |
Get Cursor Position And Shape |
| AH=04h |
Get Light Pen Position |
| AH=05h |
Set Display Page |
| AH=06h |
Clear/Scroll Screen Up |
| AH=07h |
Clear/Scroll Screen Down |
| AH=08h |
Read Character and Attribute at Cursor |
| AH=09h |
Write Character and Attribute at Cursor |
| AH=0Ah |
Write Character at Cursor |
| AH=0Bh |
Set Border Color |
| AH=0Eh |
Write Character in TTY Mode |
| AH=0Fh |
Get Video Mode |
| AH=13h |
Write String |
|
| INT 11h |
Installed by the BIOS; returns equipment list |
| INT 12h |
Installed by the BIOS or operating system; returns Conventional Memory Size |
| INT 13h |
Low Level Disk Services; installed by the BIOS or operating system; called by software programs
| AH=00h |
Reset Disk Drives |
| AH=01h |
Check Drive Status |
| AH=02h |
Read Sectors From Drive |
| AH=03h |
Write Sectors To Drive |
| AH=04h |
Verifies Sectors On Drive |
| AH=05h |
Format Track On Drive |
| AH=08h |
Get Drive Parameters |
| AH=09h |
Init Fixed Drive Parameters |
| AH=0Ch |
Seek To Specified Track |
| AH=0Dh |
Reset Fixed Disk Controller |
| AH=15h |
Get Drive Type |
| AH=16h |
Get Floppy Drive Media Change Status |
|
| INT 14h |
Routines for communicating via the serial port. Used by software programs.
| AH=00h |
Serial Port Initialization |
| AH=01h |
Transmit Character |
| AH=02h |
Receive Character |
| AH=03h |
Status |
|
| INT 15h |
Miscellaneous (System services support routines)
| AH=4FH |
Keyboard Intercept |
| AH=83H |
Event Wait |
| AH=84H |
Read Joystick |
| AH=85H |
Sysreq Key Callout |
| AH=86H |
Wait |
| AH=87H |
Move Block |
| AH=88H |
Get Extended Memory Size |
| AH=C0H |
Get System Parameters |
| AH=C1H |
Get Extended BIOS Data Area Segment |
| AH=C2H |
Pointing Device Functions |
| AH=0E8h, AL=01h (AX = 0E801h) |
Get Extended Memory Size(Newer function, since 1994). Gives results for memory size above 64 Mb. |
|
| INT 16h |
Implemented by the BIOS or operating system. Provides routines to be called by software programs which communicate with the keyboard.
| AH=00h |
Read Character |
| AH=01h |
Read Input Status |
| AH=02h |
Read Keyboard Shift Status |
| AH=10h |
Read Character Extended |
| AH=11h |
Read Input Status Extended |
| AH=12h |
Read Keyboard Shift Status Extended |
|
| INT 17h |
Print Services - used by software programs to communicate with the printer
| AH=00h |
Print Character to Printer |
| AH=01h |
Initialize Printer |
| AH=02h |
Check Printer Status |
|
| INT 18h |
Execute Cassette BASIC: True IBM computers contain BASIC in the ROM to be interpreted and executed by this routine in the event of a boot failure (called by the BIOS) |
| INT 19h |
After POST this interrupt is used by BIOS to load the operating system. |
| INT 1Ah |
Real Time Clock Services - called by software programs to communicate with the RTC
| AH=00h |
Read RTC |
| AH=01h |
Set RTC |
| AH=02h |
Read RTC Time |
| AH=03h |
Set RTC Time |
| AH=04h |
Read RTC Date |
| AH=05h |
Set RTC Date |
| AH=06h |
Set RTC Alarm |
| AH=07h |
Reset RTC Alarm |
|
| INT 1Bh |
Installed by the operating system; automatically called by INT 9 when Ctrl-Break has been pressed |
| INT 1Ch |
Called automatically by INT 08; available for use by software programs when a routine needs to be executed regularly |
| INT 1Dh |
Not to be called; simply a pointer to the VPT (Video Parameter Table), which contains data on video modes |
| INT 1Eh |
Not to be called; simply a pointer to the DPT (Diskette Parameter Table), containing a variety of information concerning the diskette drives |
| INT 1Fh |
Not to be called; simply a pointer to the VGCT (Video Graphics Character Table), which contains the data for ASCII characters 80h to FFh |
| INT 41h |
Address pointer: FDPT = Fixed Disk Parameter Table (1st hard drive) |
| INT 46h |
Address pointer: FDPT = Fixed Disk Parameter Table (2nd hard drive) |
| INT 4Ah |
Called by RTC for alarm |
| INT 70h |
IRQ8: Called by RTC |
| INT 74h |
IRQ12: Called by mouse |
| INT 75h |
IRQ13: Called by math coprocessor |
| INT 76h |
IRQ14: Called by primary IDE controller |
| INT 77h |
IRQ15: Called by secondary IDE controller |
