INT (x86 instruction)

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INT is an assembly language instruction for x86 processors that generates a software interrupt. It takes the interrupt number formatted as a byte value.^[1]

When written in assembly language, the instruction is written like this:

INT X

where X is the software interrupt that should be generated (0-255).

As is customary with machine binary arithmetic, interrupt numbers are often written in hexadecimal form, which can be indicated with a prefix 0x or with the suffix h. For example, INT 13H will generate the 20th software interrupt (0x13 is nineteen (19) in hexadecimal notation, and the count starts at 0), causing the function pointed to by the 20th vector in the interrupt table to be executed.

INT is widely used in real mode. In protected mode, INT is a privileged instruction.^[1]