INT 2F PU - Borland C++ 3.0 DPMILOAD.EXE - SET PROTECTED-MODE INTERRUPT VECTOR
        AX = FB42h
        BX = 0025h
        CL = interrupt number
        SI:DX = selector:offset of new handler
Return: DX = status (0000h,0004h,FFF2h) (see AX=FB42h/BX=0004h)
SeeAlso: INT 31/AX=0205h