Compatibility: DPMI 0.9+
Expects: AX    0201H
BL    interrupt number
CX:DX real-mode segment:offset to use for the vector
Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
Info: Changes the address of a real-mode interrupt handler.

The value return in CX must be a real-mode segment address (not a
selector).  Thus, the real-mode interrupt handler must either
reside in DOS memory (below 1MB) or you must allocate a real-mode
callback address.  See INT 31H 0100H (allocate dos mem) and
INT 31H 0303H (allocate real-mode callback address).

When hooking hardware interrupt handlers, the memory that the
handler uses must be locked.  See INT 31H 0600H (lock linear

See Also: DPMI API
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INT 31H 0201H: Set Real-mode Interrupt Vector