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INT             Interrupt                            Flags: O D I T S Z A P C
                                                            ? ? ? ? ? ? ? ? ?
INT int_number                                       IOv86

        Logic   ; Real mode
                PUSHF
                TF . 0
                IF . 0
                CALL FAR [0000:(int_number * 4)]
   
    The INT n instruction generates via software a call to an
    interrupt handler. The immediate operand, from 0 to 255, gives the
    index number into the interrupt descriptor table (IDT) of the
    interrupt service routine to be called. INT generally behaves like
    a far call except that the flags register is pushed onto the stack
    before the return address. Interrupt procedures return via the
    IRET instruction, which pops the flags and return address from the
    stack.

    In protected mode, the interrupt descriptor table (IDT) consists
    of an array of 8-byte descriptors; the descriptor for the
    interrupt invoked must indicate an interrupt, trap, or task gate.
    In real-address mode, the IDT is an array of 4-byte pointers
    (interrupt vectors).
    In protected and real address modes, the base linear address of
    the IDT is defined by the contents of the IDTR.

    This instruction is IOPL-sensitive in V86 mode.


    INT 3 is a single-byte form (the breakpoint instruction) that is
    useful for debugging.


    Note
    The first 32 interrupts are reserved by Intel for system use. Some
    of these interrupts are used for internally generated exceptions.


    Opcode      Format
    CC          INT 3
    CD ib       INT imm8
    CE          INTO


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    3             1     72      45      23+m    33      26      13   NP
    imm8          2     71      47      23+m    37      30      16   NP

                             Protected mode

                Bytes   8088    186     286     386     486     Pentium
                  1     -       -     (40-78)+m 59-99   44-71  27-82 NP