INT 2F PU - Borland C++ 3.0 DPMILOAD.EXE - SIMULATE REAL MODE INTERRUPT
        AX = FB42h
        BX = 000Dh
        CX = number of words to copy from protected-mode to real mode stack
        DL = interrupt number
        DH = flags
            bit 0: reset the interrupt controller and A20 line
        ES:DI -> real-mode call structure (see INT 31/AX=0300h)
Return: CX = status
            0000h successful
            0001h failed