INT 31 P - DPMI 1.0+ - MODIFY PAGE ATTRIBUTES
        AX = 0507h
        ESI = memory block handle
        EBX = offset in memory block of first page
        ECX = number of pages
        ES:EDX -> array of WORDs with new page attributes (see AX=0506h)
Return: CF clear if successful
        CF set on error
            AX = error code (8001h,8002h,8013h,8014h,8021h,8023h,8025h)
                (see AX=0000h)
            ECX = number of pages which have been set
Notes:  only supported by 32-bit DPMI hosts, but may be used by 16-bit clients
        if EBX is not page-aligned, it will be rounded down
SeeAlso: AX=0506h,INT 21/AX=251Eh