bios.h

• biosdisk
• _bios_keybrd, bioskey
• biosprint
• biostime
• _bios_disk
• _bios_equiplist, biosequip
• _bios_keybrd, bioskey
• _bios_memsize, biosmemory
• _bios_printer
• _bios_serialcom, bioscom
• _bios_timeofday
• _int86, int86_real, int86
• _int86x, int86x_real, int86x

biosdisk

Header

bios.h

Prototype

int biosdisk(int cmd, int drive, int head, int track, int sector, int nsects, void *buffer);

Description

biosdisk accesses interrupt 0x13 for BIOS disk operations on the drive specified by the drive argument. For floppy drives, 0 identifies the first drive, 1 is for the second drive, and so forth. This function is not available under DOSX.

cmd specifies the disk operation to perform. head, track, sector, nsects, and buffer provide further information for the command specified by cmd.

The following command values are available:

cmd	Meaning
0	Resets disk system by a hard reset; all other parameters are ignored.
1	Returns the status of the last disk operation; all other parameters are ignored.
2	Reads the specified disk sectors. The head, track, and sector arguments specify the starting sector. The nsects argument specifies the number of sectors to read. The read data is stored in buffer.
3	Writes disk sectors from memory. The head, track, and sector arguments specify the starting sector. The nsects argument specifies the number of sectors to write. The data is read from buffer.
4	Verifies sectors. The head, track, and sector arguments specify the starting sector. The nsects argument specifies the number of sectors to verify.
5	Formats a track. The head and track arguments specify the track to format. Buffer stores the sector headers.
6	Formats a track and sets bad sector flags.
7	Formats the drive beginning at a specific track.
8	Gets the current drive parameters and stores them in buffer.
9	Initializes drive-pair characteristics.
10	Does a long read.
11	Does a long write.
12	Does a disk seek.
13	Alternates disk reset.
14	Reads sector buffer.
15	Writes sector buffer.
16	Tests the specified drive to see if it is ready.
17	Recalibrates the drive.
18	Performs diagnostics on controller RAM.
19	Performs drive diagnostics.
20	Performs controller internal diagnostics.

Return Value

A status byte that can contain the following values:

0x00	Successful completion
0x01	Bad command
0x02	Address mark not found
0x03	Attempt to write to write-protected disk
0x04	Sector not found
0x05	Reset failed (hard disk)
0x06	Disk changed since last operation
0x07	Drive parameter activity failed
0x08	Direct memory access (DMA) overrun
0x09	Attempt to perform DMA across 64K
0x0A	Bad sector detected
0x0B	Bad track detected
0x0C	Usupported track
0x11	CRC/ECC corrected data error
0x20	Controller failure
0x40	Seek operation failed
0x80	Attachment failed to respond
0xAA	Drive not ready (hard disk)
0xBB	Undefined errror occurred (hard disk)
0xCC	Write fault occurred
0xE0	Status error
0xFF	Sense operation failed

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

absread
abswrite
_bios_disk

Example

/* 	Example for biosdisk 	*/ 

#include <stdio.h> 
#include <stdlib.h> 
#include <bios.h>

void main()
{   
   int result; 
   char buffer[512]; 

   printf("Attempting to read from drive A:\n"); 
   result = biosdisk(_DISK_READ, 0, 0, 1, 1, 1, buffer); 
}

_bios_keybrd, bioskey

Header

bios.h

Prototype

int _bios_keybrd(int flag);
int bioskey(int flag);

Description

The _bios_keybrd and bioskey functions pass flag to BIOS interrupt 0x16, the keyboard interrupt. The values for flag are:

Name	Value	Meaning
_KEYBRD_READ	0x00	Read the next key value from the keyboard input buffer. Wait for one if none are available.
_KEYBRD_READY	0x01	Determine if any keys are in the keyboard input buffer.
_KEYBRD_SHIFTSTATUS	0x02	Read the status of the shift keys.
_NKEYBRD_READ	0x10	Enhanced read
_NKEYBRD_READY	0x11	Enhanced ready
_NKEYBRD_SHIFTSTATUS	0x12	Enhanced shift status

Return Value

If flag is 0, the value returned is the key value. The ASCII value of the key is returned in the low byte, and the scan code in the high byte. If the low byte is 0, then the key value is not an ASCII key (it might be an arrow or function key).

If flag is 1, 0 is returned if there are no keys in the input buffer, otherwise the next key value is returned. The key value is not removed from the input buffer, and is still available to be read.

If flag is 2, the value returned is the state of the shift keys encoded into the bits as follows:

0x01	Right shift key is down
0x02	Left shift key is down
0x04	Ctrl key is down
0x08	Alt key is down
0x10	Scroll Lock is toggled
0x20	Num Lock is toggled
0x40	Caps Lock is toggled
0x80	Ins is toggled

Compatibility

DOS Windows 3.x Phar Lap DOSX

Example

/* 	Example for _bios_keybrd 	*/

#include <bios.h> 
#include <stdio.h> 
#include <stdlib.h> 

void main() 
{   
   int key, shift; 
   int lastshift; 

   while (1) 
   {   
      shift = _bios_keybrd(2); 

      /* if shift status changes */ 
      if (shift != lastshift)
	 printf("Shift = 0x% 02x \n", shift);

      /* if a key is available */ 
      if (_bios_keybrd(1)) 
      {   
	 /* read the key */ 
	 key = _bios_keybrd(0); 
	 if ((key & 0xFF) == 'q')
	     break; 
	 printf("Key = 0x% 04x \n", key); 
      } 

      lastshift = shift; 
   } 
}

Output

1. Press the right shift key down, release it.
2. Press the right shift key down, then the left, release the right then release the left.
3. Press 'q' to quit.

Output looks like this:

Shift = 0x20
Shift = 0x21
Shift = 0x20
Shift = 0x21
Shift = 0x23
Shift = 0x22
Shift = 0x20

biosprint

Header

bios.h

Prototype

int biosprint(int cmd, int abyte, int port);

Description

The biosprint function performs printer functions using BIOS interrupt 0x17. The cmd argument specifies a print command; the abyte argument specifies the character to print, and the port argument specifies the port to which the printer is connected. Port numbers are zero-based. (That is, a port argument of 0 indicates LPT1; 1 indicates LPT2, and so on.)

The cmd argument specifies one of the following operations:

cmd	operation
0	Print the character specified in the abyte argument.
1	Initialize the selected printer. Ignore abyte argument.
2	Return current printer status. Ignore abyte argument.

Return Value

The current printer status. Possible values are:

value	meaning
0x01	Printer timed out
0x08	I/ O error
0x10	Printer selected
0x20	Out of paper
0x40	Acknowledge
0x80	Printer not busy

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

_bios_equiplist
_bios_printer
_bios_serialcom

Example

/* 	Example for biosprint */ 

#include <stdio.h>
#include <bios.h>

void main () 
{   
   int status, bit_number; 
   char *description[] = 
   {   
      "Printer timed out", 
      "Unknown status", 
      "Unknown status", 
      "I/O error", 
      "Printer selected", 
      "Out of paper", 
      "Acknowledge", 
      "Printer not busy" 
   }; 

   status = biosprint (_PRINTER_STATUS, 0, 1); 
   for (bit_number = 0; bit_number < 8; bit_number += 1) 
      if (status & (1 << bit_number)) 
	 printf("% s\n", description[bit_number]); 
} 

Output

I/O error
Acknowledge
Printer not busy 

biostime

Header

bios.h

Prototype

long biostime(int cmd, long newtime);

Description

The biostime function either reads or sets the BIOS timer, using BIOS interrupt 0x1A. The cmd argument determines whether the time is to be read (cmd = 0) or set (cmd = 1). If the time is to be read, the function returns current BIOS time (in clock ticks since midnight). If the time is to be set, the BIOS time of day counter is set to the value of newtime. The BIOS timer counts ticks since midnight at a rate of approximately 18. 2 clock ticks per second.

Return Value

If the cmd argument is 0, the current value of the BIOS timer is returned. If the cmd argument is 1, the timer is set to the long value in the newtime argument.

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

_bios_timeofday

Example

/* 	Example for biostime 	*/ 

#include <stdio.h> 
#include <bios.h> 

void main () 
{   
   long ticks;

   ticks = biostime (0, 0L); 
   printf("Ticks since midnight is %d\n", ticks); 
}

Output

Ticks since midnight is 25622

_bios_disk

Header

bios.h

Prototype

int _bios_disk(unsigned service, struct diskinfo_t *info);

Description

_bios_disk is a direct interface to the BIOS disk control interrupt 0x13. service specifies the disk function desired; info specifies the disk parameters. This function is not available under DOSX.

Six services are available on a basic IBM PC. They are selected by service:

service	Value	Operation
_DISK_RESET	0	Causes a hard reset of the floppy disk controller and is useful after an error occurs. Ignores the info parameter.
_DISK_STATUS	1	Obtains the status of the last disk operation. Ignores the info parameter.
_DISK_READ	2	Reads one or more disk sectors into the memory buffer pointed to by buffer in the diskinfo_t structure. Requires all fields in the diskinfo_t structure, pointed to by info, be correctly set up.
_DISK_WRITE	3	Writes one or more disk sectors with data from the memory buffer pointed to by buffer in the diskinfo_t structure. Requires all fields in structure diskinfo_t, pointed to by info, be correctly set up.
_DISK_VERIFY	4	Verifies that disk sectors exist and are readable. Performs a CRC (cyclic redundancy check). Requires all fields in structure diskinfo_t, pointed to by info, be correctly set up.
_DISK_FORMAT	5	Formats the track specified in the head and track fields of the diskinfo_t structure pointed to by info. Only one track can be formatted in each call. The buffer field contains a set of sector markers, the format of which depends on the type of disk drive. See an IBM reference manual for marker formats.

The format of the diskinfo_t structure is:

struct diskinfo_t { 
  unsigned drive;      /* drive number*/
  unsigned head;       /* head number*/
  unsigned track;      /* track number*/
  unsigned sector;     /* start sector no.*/
  unsigned nsectors;   /* sectors to process */
  void __far *buffer;  /* Memory buffer to use */ 
};

Return Value

Depends on the service requested. Reset and format services do not return meaningful values. Read, write, and verify services return the number of sectors processed in the low byte; the high byte is 0. The status service, and if an error has occurred, the read, write, or verify service, places a code in the high byte of the return value.

The status codes are:

0x01	Invalid request / bad command
0x02	Address mark not found
0x04	Sector not found
0x05	Reset failure
0x07	Drive parameter activity failure
0x09	DMA overrun
0x0a	Bad sector flag detected
0x10	Data read (ECC) error
0x11	Corrected data read (ECC) error
0x20	Controller failure
0x40	Seek error
0x80	Disk timed out / not responding
0xaa	Drive not ready
0xbb	Undefined error
0xcc	Write fault
0xe0	Status error
0XFF	Sense operation failed

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

biosdisk

Example

/* 	Example for _bios_disk 	*/ 

#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h> 

int lowbytes (int tomask) 
{   
   return (tomask & 0x00FF); 
} 

int highbytes (int toshift) 
{   
   return (toshift >> 8); 
} 

void main() 
{   
   int status; 
   struct diskinfo_t disk; 

   status = _bios_disk (1, &disk); 
   status = highbytes (status); 
   if (status != 0) 
      printf("Last disk operation had error %x\n", status); 
   else 
      printf("Last disk operation completed OK.\n"); 
}

Output

Last disk operation completed OK.

_bios_equiplist, biosequip

Header

bios.h

Prototype

int _bios_equiplist(void);

Synonym

biosequip

Description

The _bios_equiplist function executes BIOS interrupt 0x11 to determine what equipment is present.

Return Value

A register value indicating what equipment is installed.

Bit	Meaning
15,14	The number of printers attached
13	Not used
12	1 if a game adaptor is attached
11,10,9	The number of serial (RS232) ports
8	Not used
7,6	The number of diskette drives (maximum 4)
5,4	The initial video mode
00	Not used
01	40x25 color
10	80x25 color
11	Monochrome
3,2	Planar RAM size (11 = 64k which is normal)
1	Not used
0	Set if there are any diskette drives

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

_bios_keybrd
_bios_memsize
_bios_printer
_bios_serialcom
_bios_disk

Example

/* 	Example for _bios_equiplist 	*/ 

#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h> 

#define GAME_ADAPTOR 0x0c

void main() 
{   
   unsigned equipment;

   equipment = _bios_equiplist(); 

   if (equipment & GAME_ADAPTOR) 
      printf("Game adaptor installed.\n"); 
   else 
      printf("No game adaptor installed.\n"); 

}

Output

Game adaptor installed.

_bios_keybrd, bioskey

Header

bios.h

Prototype

int _bios_keybrd(int flag);
int bioskey(int flag);

Description

The _bios_keybrd and bioskey functions pass flag to BIOS interrupt 0x16, the keyboard interrupt. The values for flag are:

Macro	flag	Meaning
_KEYBRD_READ	0x00	Read the next key value from the keyboard input buffer. Wait for one if none are available.
_KEYBRD_READY	0x01	Determine if any keys are in the keyboard input buffer.
_KEYBRD_SHIFTSTATUS	0x02	Read the status of the shift keys.
_NKEYBRD_READ	0x10	Enhanced read
_NKEYBRD_READY	0x11	Enhanced ready
_NKEYBRD_SHIFTSTATUS	0x12	Enhanced shift status

Return Value

If flag is 0, the value returned is the key value. The ASCII value of
the key is returned in the low byte, and the scan code in the high
byte. If the low byte is 0, then the key value is not an ASCII key (it
might be an arrow or function key). If flag is 1, 0 is returned if
there are no keys in the input buffer, otherwise the next key value is
returned. The key value is not removed from the input buffer, and is
still available to be read. If flag is 2, the value returned is the state
of the shift keys encoded into the bits as follows:

0x01	Right shift key is down
0x02	Left shift key is down
0x04	Ctrl key is down
0x08	Alt key is down
0x10	Scroll Lock is toggled
0x20	Num Lock is toggled
0x40	Caps Lock is toggled
0x80	Ins is toggled

Compatibility

DOS Windows 3.x Phar Lap DOSX

Example

/* 	Example for _bios_keybrd 	*/

#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h> 

void main() 
{   
   int key, shift; 
   int lastshift; 

   while (1) 
   {   
      shift = _bios_keybrd (2); 

      /* if shift status changes */ 
      if (shift != lastshift)
	 printf("Shift = 0x% 02x \n", shift);

      /* if a key is available */ 
      if (_bios_keybrd(1)) 
      {   
	 /* read the key */ 
	 key = _bios_keybrd(0); 
	 if ((key & 0xFF) == 'q') break; 
	 printf("Key = 0x% 04x \n", key); 
      } 

      lastshift = shift; 
   } 
}

Output

Press the right shift key down, release it.
Press the right shift key down, then the left,
release the right
then release the left. Press 'q' to quit.
Output looks like this:

Shift = 0x20
Shift = 0x21
Shift = 0x20
Shift = 0x21
Shift = 0x23
Shift = 0x22
Shift = 0x20

_bios_memsize, biosmemory

Header

bios.h

Prototype

int _bios_memsize(void);

Synonym

biosmemory()

Description

The function _bios_memsize executes a BIOS interrupt 0x12, which is the memory size determination routine.

Return Value

Returns the maximum number of contiguous 1K memory blocks which are present, as an integer.

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

_bios_equiplist

Example

/* 	Example for _bios_memsize 	*/

#include <bios.h>
#include <stdio.h> 
#include <stdlib.h>

void main() 
{   
   printf("The memory size of this system is %dK\n",
	_bios_memsize());
}

Output

The memory size of this system is 636K

_bios_printer

Header

bios.h

Prototype

int _bios_printer(unsigned service, unsigned printer, unsigned data);

Description

_bios_printer executes a BIOS interrupt 0x17, which is the printer interface routine. service determines which of three possible operations to perform:

service	Value	Operation
_PRINTER_WRITE	0	Write the low order byte of data to the printer which was specified in the printer argument.
_PRINTER_INIT	1	Initialize the selected printer. Ignore the data argument.
_PRINTER_STATUS	2	Return the current printer status. Ignore the data argument.

_bios_printer is not supported under windows.

Return Value

The low byte of the return value, for all three services, contains the printer status. Possible values are:

0x01	Printer timed out
0x08	I/ O error
0x10	Printer selected
0x20	Out of paper
0x40	Acknowledge
0x80	Printer not busy

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

_bios_equiplist
biosprint

Example

/* 	Example for _bios_printer 
*/ 
#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h> 

void main() 
{   

   unsigned i, data = 36; 
   unsigned status; 

   printf("Place printer offline and press [Enter]\n"); 
   getchar (); 
   status = _bios_printer(2, 0, data); 
   printf("Status with printer offline: %x\n", status); 

   printf("Press [Enter] to initialize printer\n"); 
   getchar(); 
   status = _bios_printer(1, 0, data); 
   printf("Status after printer initialized: %x\n", status);

   printf("Press [Enter] to print\n"); 
   getchar(); 
   for (i= 0; i> 10; i++) 
      _bios_printer(0, 0, data); 

   status = _bios_printer(0, 0, '\n'); 
   printf("Status after printing %d %c's:% x\n", i, data, status); 
}

Output

Place printer offline and press [Enter]
Status with printer offline:
Press [Enter] to initialize printer
Status after printer initialized:
Press [Enter] to print
Status after printing $'s: 

_bios_serialcom, bioscom

Header

bios.h

Prototype

int _bios_serialcom(unsigned service, unsigned port, unsigned data);

Synonym

bioscom()

Description

This function uses the BIOS to provide serial RS232 operations. The function is not supported under Microsoft Windows. The IBM BIOS allows only polled operation of the serial ports, not interrupt operation. The port argument is the number of the serial port to address. This is set to 0 for COM1 and 1 for COM2.

Four services are provided:

_COM_INIT, or 0	Set up the serial port as specified in the data argument (see below).
_COM_SEND, or 1	Transmit the data character through the selected serial port
_COM_RECEIVE, or 2	Accepts an input character through the selected serial port.
_COM_STATUS, or 3	Return the current status of the selected serial port.

The data argument for the initialize service is created by OR'ing together one value from each of the following categories.

Baud Rate	Value
_COM_110	0
_COM_150	32
_COM_300	64
_COM_600	96
_COM_1200	128
_COM_2400	160
_COM_4800	192
_COM_9600	224

Data Word Length	Value
_COM_CHR7	2
_COM_CHR8	3

# of Stop Bits	Value
_COM_STOP1	0
_COM_STOP2	4

Parity	Value
_COM_NOPARITY	0
_COM_ODDPARITY	8
_COM_EVENPARITY	24

Return Value

A 16-bit integer whose high byte contains status bits. The low byte
varies according to the service requested. High byte status bits are:

Bit	Meaning when set
15	Timed out
14	Transmitter Shift register empty
13	Transmitter Holding register empty
12	Break detected
11	Framing Error
10	Parity Error
9	Overrun Error
8	Data Ready

If the send service is requested but data cannot be sent, bit 15 is set.

If the receive service is requested, the byte read is returned in the low byte. If an error occurrs, at least one bit in the high byte is set to indicate the source of the error.

If the service requested is either initialize or status, additional status information are returned in the low byte:

Bit	Meaning when set
7	Data Carrier Detect (DCD) state
6	Ring Indicator (RI) state
5	Data Set Ready (DSR) state
4	Clear To Send (CTS) state
3	Change in DCD
2	Change in RI
1	Change in DSR
0	Change in CTS

Compatibility

DOS Windows 3.x Phar Lap DOSX

Example

/* 	Example for _bios_serialcom 	*/

#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h>

void main() 
{   
   unsigned com1_status;

   com1_status = _bios_serialcom (3,0,0); 
   printf("Com1 status : %x\n", com1_status); 
}

Output

Com1 status : 6000

_bios_timeofday

Header

bios.h

Prototype

int _bios_timeofday(unsigned mode, long *btime);

Description

_bios_timeofday provides an interface to the IBM BIOS time of day functions, interrupt 0x1A (26). mode determines whether the time is to be read or set:

mode	Value	Meaning
_TIME_GETCLOCK	0	Retrieve time
_TIME_SETCLOCK	1	Set time

If the time is to be read, the current BIOS time (in clock ticks since midnight) is placed in the long integer pointed to by btime. Otherwise, the BIOS time of day counter is set to the value of that long. There are approximately 18. 2 clock ticks per second.

Return Value

If mode is 0, the function returns 1 if the system clock has passed midnight since the last time it was read. Otherwise, it returns 0. If mode is 1, no meaningful value is returned.

Compatibility

DOS Windows 3.x Phar Lap DOSX

See Also

biostime

Example

/* 	Example for _bios_timeofday 	*/ 

#include <bios.h> 
#include <stdio.h> 
#include <stdlib. h>

void main() 
{   
   unsigned hours, minutes; 
   long btime; 

   _bios_timeofday (0,& btime);

   btime = (btime* 10)/ 182; 
   minutes = (unsigned) btime / 60; 
   hours = minutes / 60; 
   minutes %= 60; 

   printf("The time is %2d:%2d\n", 
	     hours, minutes); 
}

Output

The time is 15:34

_int86, int86_real, int86

Header

dos.h

Prototype

int _int86(int intnum, union _REGS *regsin, union REGS *regsout);

Description

int int86_real(int intnum, union _REGS *regsin, union REGS *regsout); The _int86 functions perform a software interrupt, where intnum is the interrupt number (0.. 255), regsin is a pointer to a structure containing the values of the registers AX, BX, CX, DX, SI and DI to be passed to the interrupt, and regsout is a pointer to a structure into which the return values of the registers will be written.

The _REGS structure is defined in dos. h. Consult your system hardware and software manuals to determine what the interrupt numbers are and what they do on your machine.

In the 32-bit memory models, the functions _bdos, bdos, bdosx, _int86, int86, _int86x, int86x, _intdos, intdos, _intdosx, and intdosx filter parameters sent to the real mode interrupt. For example, if DOS function 40h (write) is detected, the source buffer is copied to a buffer in conventional memory (dos-buffer) and a pointer to dos-buffer is passed to DOS, since DOS could not properly use the buffer located in extended memory. If the information passed is larger than dos-buffer, there are multiple calls to DOS to transfer all information, which may be much larger than 64k. Where pointers are passed to these functions, they are assumed to contain protected mode addresses. The filtering routine used for these functions assumes that all far pointers passed in registers to DOS have a segment address of DGROUP. If you use int86x to execute INT 21h and specify selectors other than DGROUP, the results will be unpredictable. It is possible to bypass this filtering by using the function int_86real instead of int86. This function bypasses all protected mode filtering in both the Phar Lap and DOSX extenders and executes the interrupt in real mode. It can be used to retrieve real mode segment values from the BIOS or from DOS if desired. Under the X memory model, not all DOS calls are supported in the filtering process. DOS calls (listed in hex) that are completely supported include:

0..9, b, d, e, 19, 2a..2e, 30, 33, 36, 39..43, 45..47, 4c..4f, 54..58, 5b..5c, 63, 66..68

Partial support is provided for:

0c	AL = 0AH not supported
1a	DTA set to a location in conventional memory
2f	Get DTA returns protected mode address of DTA in conventional memory
44	Subfunctions 2, 3, 4, 5, c, and d are not supported
59	Information at ES: DI not available
5a	Information at ds: dx is not available
62	returns protected mode selector, not real mode segment

Functions not supported:

0a, 0f..17, 1b..1c, 21..29, 31, 35, 38, 48..4b, 5e..5f, 65

Synonym

Function: int86

Return Value

The _int86 function returns the value in the AX register at the completion of the interrupt. The state of the carry flag can be determined from x. cflag in regsout. Do not use _int86 for interrupts 0x25 or 0x26. Use dos_abs_disk_read / write for those.

Compatibility

_int86: DOS Windows 3. x Phar Lap/ DOSX int86_real: DOS Windows 3. x Phar Lap/ DOSX

See Also

_int86x
int86x_real
_intdos

Example

/* 	Example for _int86 */ 

#include <dos.h> 
#include <stdio.h>

void main () 
{   
   union _REGS inregs, outregs; 
   unsigned char last_flags, new_flags; 
   int n; 
   char *description[] = 
   {   
      "right shift", 
      "left shift", 
      "control", 
      "alt", 
      "scroll lock", 
      "num lock", 
      "caps lock", 
      "insert" 
   }; 
   printf("Press keyboard toggles and shift 
	     keys\n"); 
   printf("Press ctrl-break to quit\n"); 
   for (;;) 
   {   
      inregs. h. ah = 2; /* get keyboard flags */ 
	     _int86 (0x16, &inregs, &outregs); 
      new_flags = outregs. h. al ^ last_flags; 
      if (new_flags) 
	 for (n = 0; n < 8; n += 1) 
	     if (new_flags & (1 << n)) 
		 printf("% s %s\n", description[n], 
		    outregs. h. al & (1 << n)? "on": 
				      "off"); 
      last_flags = outregs. h. al; 
   } 
} 

Output

Press keyboard toggles and shift keys
Press ctrl-break to quit
alt on
left shift on
left shift off
alt off
insert on
right shift on
alt on
control on
right shift off
control off
alt off
num lock off
num lock on
control on
^C

_int86x, int86x_real, int86x

Header

dos.h

Prototype

int _int86x(int intnum, union _REGS *regsin, union _REGS *regsout, struct _SREGS *segregs);

int int86x_real(int intnum, union _REGS *regsin, union _REGS *regsout, struct _SREGS *segregs);

Description

The _int86x and int86x_real functions perform a software interrupt, where intnum is the interrupt number (0 through 255). regsin is a pointer to a structure containing the values of the registers AX, BX, CX, DX, SI and DI to be passed to the interrupt. segregs is a pointer to a structure containing the values of the segment registers to be passed to the interrupt. These functions also are used to return the values in the segment registers after the interrupt has completed. regsout is a pointer to a structure into which the return values of the registers will be written. The _REGS, and _SREGS structures are defined in dos. h. Consult your system hardware and software manuals to determine what the interrupt numbers are and what they do on your machine.

The int86x_real function is used with the 32-bit models. For a further explanation of performing interrupts in the 32-bit model, see _int86, int86_real.

Synonym

Function: int86x

Return Value

The _int86x and int86x functions return the value in the AX register at the completion of the interrupt. The state of the carry flag can be determined from x. cflag in regsout. Do not use _int86x for interrupts 0x25 or 0x26. For _int86x, if an error occurs, the cflag field in regsout is non-zero and _doserrno is set to the corresponding error code.

Compatibility

_int86x: DOS Windows 3.x Phar Lap/ DOSX
int86x_real: DOS Windows 3.x Phar Lap/ DOSX

See Also

_int86
int86_real
_intdos
_intdosx

Example

See _int86