INT 31 P - DPMI 0.9+ - PHYSICAL ADDRESS MAPPING
        AX = 0800h
        BX:CX = physical address (should be above 1 MB)
        SI:DI = size in bytes
Return: CF clear if successful
            BX:CX = linear address which maps the requested physical memory
        CF set on error
            AX = error code (DPMI 1.0+) (8003h,8021h) (see AX=0000h)
Notes:  implementations may refuse this call because it can circumvent protects
        the caller must build an appropriate selector for the memory
        do not use for memory mapped in the first megabyte
SeeAlso: AX=0508h,AX=0509h,AX=0801h,INT 21/AX=250Ah,INT 21/AX=EB05h