List Of Interrupts

Print Screen
Interrupt	0x5
Returns	Nothing
Notes	Send screen contents to printer. Works in text mode.
Get Peripheral Equipment List Interrupt          0x11 Input Nothing Returns  AX = equipment list Notes  Bit setting for AX are as follows: 00 = disk drive present/absent (0:absent, 1:present) 01 = math co-processor (0:absent, 1:present) 02-03 = RAM in 16 kb blocks 04-05 = initial video mode 00 = (unused) 01 = 40 x 25 colour 10 = 80 x 25 colour 11 = 80 x 25 mono 06-07 = number of disk drives 08 = DMA present (0:present, 1:absent ) 09-11 = number of serial ports 12 = game port (0:absent, 1:present) 13 = serial printer 14-15 = number of printers Reset Disk Controller Interrupt          0x13 Input AH = 0x0 DL = drive 0x00-0x7F floppy disk 0x80-0xFF fixed disk Returns  Nothing Get Disk Status Interrupt          0x13 Input AH = 0x01 DL = drive 0x00-0x7F floppy disk 0x80-0xFF fixed disk Returns  AL = status code Note Status code values in AL are AL = 0 : no error AL = 1 : bad command AL = 2 : address mark not found AL = 3 : write attempt to write-protected disk (F) AL = 4 : sector not found AL = 5 : reset failed (H) AL = 6 : floppy disk removed (F) AL = 7 : bad parameter table (H) AL = 8 : DMA overrun (F) AL = 9 : DMA across 64 kb boundary AL = A : bad sector flag (H) AL = B : bad track flag (H) AL = C : media type not found (F) AL = D : invalid number of sectors on format (H) AL = E : control data address mark detected (H) AL = F : DMA arbitration level out of range (H) AL = 10 : bad CRC AL = 11 : ECC corrected data error (H) AL = 20 : NEC controller failure AL = 40 : seek failed AL = 80 : time out (failed to respond) AL = AA : drive not ready (H) AL = BB : undefined error (H) AL = CC : write fault (H) AL = E0 : status register error (H) AL = FF : sense operation failed (H) H = fixed disk only, F = floppy disk only Read Disk Sectors Interrupt          0x13 Input AH = 0x02 AL = number of sectors CH = track number CL = sector number DH = head number DL = drive number 0x00-0x7F floppy disk 0x80-0xFF fixed disk ES:BX = pointer to buffer Returns  If function successful Carry flag = clear AH = 0x00 AL = number of sectors read If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Write disk sectors Interrupt          0x13 Input AH = 0x03 AL = number of sectors CH = track number CL = sector number DH = head number DL = drive number 0x00-0x7F floppy disk 0x80-0xFF fixed disk ES:BX = pointer to buffer Returns  If function successful Carry flag = clear AH = 0x00 AL = number of sectors written If function unsuccessful Carry flag = set AH = status code CF = success/failure flag AH = status code (refer interrupt 0x13, function 0x01) Verify Disk Sectors Interrupt 0x13 Input AH = 0x04 AL = number of sectors CH = track number CL = sector number DH = head number DL = drive number 0x00-0x7F floppy disk 0x80-0xFF fixed disk ES:BX = pointer to buffer Returns  If function successful Carry flag = clear AH = 0x00 AL = number of sectors verified If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Format Disk Track Interrupt 0x13 Input AH = 0x05 AL = number of sectors CH = track number CL = sector number DH = head number DL = drive number ES:BX = pointer to 4-byte address fields consisting of byte 0 = track byte 1 = head byte 2 = sector byte 3 = bytes/sector 0 if 128 bytes per sector 1 if 256 bytes per sector 2 if 512 bytes per sector (standard) 3 if 1024 bytes per sector Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Get Current Drive Parameters Interrupt 0x13 Input AH = 0x08 DL = drive 0x00-0x7F floppy disk 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear BL = drive type (PC/AT floppy disks) 0x01 if 360 kb, 40 track, 5.25" 0x02 if 1.2 mb, 80 track, 5.25" 0x03 if 720 kb, 80 track, 3.5" 0x04 if 1.44 mb, 80 track, 3.5" CH = low 8 bits of maximum cylinder number CL = bits 6-7 high-order 2 bits of maximum cylinder number         bits 0-5 maximum sector number DH = maximum head number DL = number of drives ES:DI = segment:offset of disk drive parameter table If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) On PC/XT this service is supported on fixed disk only. Initialize Two Fixed Disk Base Tables Interrupt 0x13 Input AH = 0x09 DL = drive 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes  On PC/XT vector for interrupt 0x41 must point to disk parameter table. On PC/AT and above vector for interrupt 0x41 must point to table for drive 0; and the one for interrupt 46 must point to table for drive 1. Read Long Interrupt 0x13 Input AH = 0x0A AL = number of sectors DL = drive 0x80-0xFF fixed disk DH = head number CH = cylinder number CL = sector number (see notes) ES:BX = pointer to buffer Returns  If function successful Carry flag = clear AH = 0x00 AL = number of sectors read If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes  This service is supported on fixed disks only. The upper 2 bits of the 10-bit cylinder number are placed in the upper 2 bits of register CL. Write Long Interrupt 0x13 Input AH = 0x0B AL = number of sectors DL = drive 0x80-0xFF fixed disk DH = head number CH = cylinder number CL = sector number (see notes) ES:BX = pointer to buffer Returns  If function successful Carry flag = clear AH = 0x00 AL = number of sectors written If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. The upper 2 bits of the 10-bit cylinder number are placed in the upper 2 bits of register CL. Seek To Cylinder Interrupt 0x13 Input AH = 0x0C CH = lower 8 bits of cylinder CL = upper 2 bits of cylinder in bits 6-7 DH = head DL = drive 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. Reset Fixed Disk System Interrupt 0x13 Input AH = 0x0D DL = drive 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. Test For Drive Ready Interrupt 0x13 Input AH = 0x10 DL = drive ID 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. Recalibrate Drive Interrupt 0x13 Input AH = 0x11 DL = drive ID 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. Controller Diagnostics Interrupt 0x13 Input AH = 0x14 Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This service is supported on fixed disks only. Get Disk Type Interrupt 0x13 Input AH = 0x15 DL = drive ID 0x00-0x7F floppy disk 0x80-0xFF fixed disk Returns  If function successful Carry flag = clear AH = disk type code CX:DX = number of 512-byte sectors, when AH = 3 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This function is not supported on the PC or PC/XT. Disk type codes are: AH = 0 : disk non-existent AH = 1 : disk, no change detection present AH = 2 : disk change detection present AH = 3 : fixed disk Get Disk Change Status Interrupt 0x13 Input AH = 0x16 Returns  DL = drive that had disk change 0x00-0x7F floppy disk AH = disk change status Notes This function is not supported on the PC or PC/XT. Status codes in AH are: 00 = no disk change 01 = disk changed Set Disk Type Interrupt 0x13 Input AH = 0x17 AL = floppy disk type code 0x00 not used 0x01 320/360 kb floppy disk in 360 kb drive 0x02 320/360 kb floppy disk in 1.2 mb drive 0x03 1.2 mb floppy disk in 1.2 mb drive 0x04 720 kb floppy disk in 720 kb drive DL = drive 0x00-0x7F floppy disk Returns  If function successful Carry flag = clear AH = 0x00 If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01) Notes This function is not supported on the PC or PC/XT. Disk type codes for AL are: AL = 00 : no disk AL = 01 : regular disk, regular drives AL = 03 : high-capacity disk in high-capacity drives Set Media Type For Format Interrupt 0x13 Input AH = 0x18 CH = number of cylinders CL = sectors per track DL = drive 0x00-0x7F floppy disk Returns  If function successful Carry flag = clear AH = 0x00 ES:DI = segment:offset of disk parameter table for media type If function unsuccessful Carry flag = set AH = status code (refer interrupt 0x13, function 0x01)   Read Next Keyboard Character Interrupt 0x16 Input AH = 0x00 Returns  AH = scan code AL = ASCII code Report Whether Character Ready Interrupt 0x16 Input AH = 0x01 Returns  zero flag = 0 - character available to be received,                 1 - no character in keyboard buffer AH = scan code AL = ASCII code Get shift status Interrupt 0x16 Input AH = 0x02 Returns  AL shift status bits Notes Shift status bits are Bit 0 = 1 : Right shift depressed Bit 1 = 1 : Left shift depressed Bit 2 = 1 : Ctrl depressed Bit 3 = 1 : Alt depressed Bit 4 = 1 : Scroll Lock on Bit 5 = 1 : Num Lock on Bit 6 = 1 : Caps Lock on Bit 7 = 1 : Insert on   Reboot  Computer Interrupt 0x19 Input Nothing   Set Disk Transfer Address Input AH = 0x01A DS:DX = address of disk transfer area Returns  Nothing Notes  Useful if you want to write your own DIR command Get FAT Information For Any Drive Input AH = 0x01C DL = Drive number ( 0 = default, 1 = A, 2 = B, etc.) Returns  If function successful DS:BX = Segment offset of Media descriptor 0xF8 - Hard disk 0xFC - 5.25 inch single sided, 9 sector 0xFD - 5.25 inch double sided, 9 sectors 0xFE - 5.25 inch single sided, 8 sectors 0xFF - 5.25 inch double sided, 8 sectors DX = number of clusters AL = number of sectors/cluster CX = bytes/sector If function unsuccessful (invalid drive or critical error) AL = 0xFF Get Disk Free Space Input AH = 0x36 DL = Drive number ( 0 = default, 1 = A, 2 = B, etc.) Returns  If function successful AX = number of sectors/cluster BX = number of available clusters on disk CX = number of bytes/sector DX = Total number of clusters on drive If function unsuccessful (drive invalid) AX = 0xFFFF Notes  Useful if you want to check whether a file can be accommodated on a disk or not. Make Directory Input AH = 0x39 DS:DX = segment:offset address of directory name Returns  If function successful Carry flag = clear If function unsuccessful Carry flag = set AX = error code Remove Directory Input AH = 0x3A DS:DX = segment:offset address of directory name Returns  If function successful Carry flag = clear If function unsuccessful Carry flag = set AX = error code Change Directory Input AH = 0x3B DS:DX = segment:offset address of directory name Returns  If function successful Carry flag = clear If function unsuccessful Carry flag = set AX = error code Delete File Input AH = 0x41 DS:DX = segment:offset address of file name Returns  If function successful Carry flag = clear If function unsuccessful Carry flag = set AX = error code Notes  Wild card characters not allowed in file name. Get File Attributes Input AH = 0x43 AL = 0 DS:DX = segment:offset address of file name Returns If function successful Carry flag = clear CX = Current file attributes If function unsuccessful Carry flag = set AX = error code Notes  File attributes are bit encoded. Set File Attributes Input AH = 0x43 AL = 1 CX = file attributes DS:DX = segment:offset address of file name Returns If function successful Carry flag = clear CX = Current file attributes If function unsuccessful Carry flag = set AX = error code Notes  File attributes are bit encoded. Get Current Directory Input AH = 0x47 DL = Drive number (0 = default, 1 = A, 2 = B, etc.) DS:DI= segment:offset address of buffer where DOS places the current directory name. Returns If function successful Carry flag = clear and buffer is filled with full pathname from root of current directory. If function unsuccessful Carry flag = set AX = error code Notes  File attributes are bit encoded. Find First Matching File Input AH = 0x4E DS:DX = segment:offset address of file name. Filename can contain wild card characters CX = file attributes used while searching Returns If function successful ( matching file found ) Carry flag = clear Disk transfer area is set up with the file information. The file information is 43 bytes long and contains following details: 0 - 20 reserved bytes 21 file attribute 22 - 23 time of creation/modification 24 - 25 date of creation/modification 26 - 30 file size 31 - 42 file name If function unsuccessful (no matching files) Carry flag = set AX = error code Notes  This service is useful if you want to write your own DIR command Find Next Matching File Input AH = 0x4F Assumes that DTA points to buffer used by previous successful interrupt 0x21, function 0x4E or 0x4E. Returns If function successful ( matching file found ) Carry flag = clear Disk transfer area is set up with the file information. The file information is 43 bytes long and contains detail given in service 0x4E : If function unsuccessful (no more matching files) Carry flag = set AX = error code Notes  This service is useful if you want to write your own DIR command Rename File Input AH = 0x56 DS:DX = segment:offset address of file to be renamed. Wild card characters are not allowed. ES:DI = segment:offset address of new name of file. Wild card characters are not allowed. Returns If function successful  Carry flag = clear If function unsuccessful  Carry flag = set AX = error code Notes  The path and new file name can be different than original. However, the drive must be same. In MS-DOS version 3.0 and later, this function can also be used to rename directories.   Set Video Mode Interrupt          0x10 Input AH = 0x00 AL = video mode Returns  Nothing Notes  Video modes in AL are: 0x0 : 40 x 25 text, 16 grey 0x1 : 40 x 25 text, 16/8 colour 0x2 : 80 x 25 text, 16 grey 0x3 : 80 x 25 text, 16/8 colour 0x4 : 320 x 200 graphics, 4 colour 0x5 : 320 x 200 graphics, 4 grey 0x6 : 640 x 200 graphics, mono 0x7 : 80 x 25 text, mono 0x8 : 160 x 200 graphics, 16 colour 0x9 : 320 x 200 graphics, 16 colour 0xA : 640 x 200 graphics, 4 colour 0xD : 320 x 200, 16 colour EGA, VGA 0xE : 640 x 200, 16 colour EGA, VGA 0xF : 640 x 350, mono on EGA, VGA 0x10 : 640 x 350, 4 or 16 colour EGA, VGA 0x11 : 640 x 480, graphics, 2 colours 0x12 : 640 x 480, graphics, 16 colours, VGA 0x13 : 320 x 200, graphics, 256 colours, VGA Set Cursor Size Interrupt          0x10 Input AH = 0x01 CH = starting scan line CL = ending scan line Returns  Nothing Notes  Cursor blinking is under hardware control. Set Cursor Position Interrupt          0x10 Input AH = 0x02 BH = display page number DH = row DL = column Returns  Nothing Notes  0,0 is upper left. To turn off the cursor, set to (0,25) Read Current Cursor Position Interrupt          0x10 Input AH = 0x03 BH = display page number Returns  CH = starting scan line CL = ending scan line DH = row DL = column Set Active Display Page Interrupt          0x10 Input AH = 0x05 AL = page number Returns  Nothing Scroll Window Up Interrupt          0x10 Input AH = 0x06 AL = lines to scroll up BH = filler attribute CH = upper row CL = left column DH = lower row DL = right column Returns  Nothing Scroll Window Down Interrupt          0x10 Input AH = 0x07 AL = lines to scroll down BH = filler attribute CH = upper row CL = left column DH = lower row DL = right column Returns  Nothing Set Colour Palette Interrupt          0x10 Input AH = 0x0B BH = palette colour ID BL = colour to be used with palette Notes  This works for CGA/EGA/VGA only. Write Pixel Dot Interrupt 0x10 Input AH = 0x0C AL = pixel value CX = pixel column DX = pixel row BH = page Returns Nothing Read Pixel dot Interrupt 0x10 Input AH = 0x0D BH = page CX = pixel column DX = pixel row Returns AL = pixel value Get Current Video Mode Interrupt 0x10 Input AH = 0x0F Returns AH = number of character columns on screen AL = video mode BH = page number Get Memory Size In kb Interrupt 0x12 Input Nothing Returns AX = memory size (in kb)   Delay Interrupt 0x15 Input AH = 0x86 CX, DX = number of microseconds to wait. Returns  Nothing Get extended memory size Interrupt 0x15 Input AH = 0x88 Returns  Nothing Notes  Applies to AT and later only. Send One Byte To Printer Interrupt 0x17 Input AH = 0x00 AL = character DX = printer number (0 = LPT1, 1 = LPT2, 2 = LPT3) Returns  AH = success/failure code Notes Status code values are Bit 0 = 1 : time out Bit 3 = 1 : I/O error Bit 4 = 1 : printer selected Bit 5 = 1 : out of paper Bit 6 = 1 : printer acknowledge Bit 7 = 1 : printer not busy Initialise  Printer Interrupt 0x17 Input AH = 0x01 DX = printer number (0 = LPT1, 1 = LPT2, 2 = LPT3) Returns  AH = status code (refer interrupt 0x13, function 0x01) Notes Status code is the same as for service 0x01. Get Printer Status Interrupt 0x17 Input AH = 0x02 DX = printer number (0 = LPT1, 1 = LPT2, 2 = LPT3) Returns  AH = status code (refer interrupt 0x13, function 0x01) Notes Status code is the same as for service 0x01. Read Contents Of The Clock Tick Counter Interrupt 0x1A Input AH = 0x00 Returns AL = midnight signal, 0x00 if midnight passed since last read,         non-zero otherwise CX = tick count, high portion DX = click count, low portion Set Value In Clock Tick Counter Interrupt 0x1A Input AH = 0x01 CX = tick count, high portion DX = click count, low portion Returns Nothing Get Current Time From CMOS Time/Date Chip Interrupt 0x1A Input AH = 0x02 Returns CH = hours in Binary Coded Decimal (BCD) CL = minutes in BCD DH = seconds in BCD DL = 1 if daylight saving time, 0 if standard time Notes   Applies to AT and later only. Set Time In CMOS Time/Date Chip Interrupt 0x1A Input AH = 0x03 CH = hours in Binary Coded Decimal (BCD) CL = minutes in BCD DH = seconds in BCD DL = 1 if daylight saving time, 0 if standard time Returns Nothing Read date from CMOS time/date chip Interrupt 0x1A Input AH = 0x04 Returns CL = day in Binary Coded Decimal (BCD) DH = month in BCD CL = year in BCD CH = century in BCD Set Date In CMOS Time/Date Chip Interrupt 0x1A Input AH = 0x05 CL = day in Binary Coded Decimal (BCD) DH = month in BCD CL = year in BCD CH = century in BCD Returns Nothing Set Alarm In CMOS Date/Time Chip Interrupt 0x1A Input AH = 0x06 CH = hours in Binary Coded Decimal (BCD) CL = minutes in BCD DH = seconds in BCD Returns If function successful Carry flag = clear If function unsuccessful  Carry flag = set Notes  The program using this routine must place the address of its interrupt handler for the alarm in the vector for interrupt 0x4A. Reset Alarm Interrupt 0x1A Input AH = 0x07 Returns Nothing