INT 31 P - DPMI 0.9+ - GET REAL MODE INTERRUPT VECTOR
        AX = 0200h
        BL = interrupt number
Return: CF clear
        CX:DX = segment:offset of real mode interrupt handler
Note:   the DPMI implementation is required to support all 256 vectors
SeeAlso: AX=0204h,INT 21/AX=2503h