int86x

interrupt the CPU

Synopsis:

#include <i86.h>
int int86x( int inter_no,
            const union REGS *in_regs,
            union REGS *out_regs,
            struct SREGS *seg_regs );

Description:

The int86x() function causes the computer's central processor (CPU) to be interrupted with an interrupt whose number is given by inter_no. Before the interrupt, the CPU registers are loaded from the structure located by in_regs, and the DS and ES segment registers are loaded from the structure located by seg_regs.

All of the segment registers must contain valid values. Failure to do so will cause a segment violation when running in protect mode. If you don't care about a particular segment register, then it can be set to 0, which will not cause a segment violation. The function segread() can be used to initialize seg_regs to their current values.

Following the interrupt, the structure located by out_regs is filled with the contents of the CPU registers. The in_regs and out_regs structures may be located at the same location in memory. The original values of the DS and ES registers are restored. The structure seg_regs is updated with the values of the segment registers following the interrupt.

Returns:

the value of the CPU AX register after the interrupt

See also:

int386(), int386x(), int86(), intr(), segread()

Examples:

#include <stdio.h>
#include <i86.h>

/* get current mouse interrupt handler address */

void main()
  {
    union REGS r;
    struct SREGS s;

    r.h.ah = 0x35;  /* DOS get vector */
    r.h.al = 0x33;  /* interrupt vector 0x33 */
    int86x( 0x21, &r, &r, &s );
    printf( "mouse handler address=%4.4x:%4.4x\n",
        s.es, r.w.bx );
  }

Classification:

Intel

Systems:

DOS/16, Windows, Win386, QNX/16, DOS/PM