INT 21 - European MSDOS 4.0 - "CREATMEM" - CREATE A SHARED MEMORY AREA
        AX = 8400h
        BX = size in bytes (0000h = 65536)
        CX = flags
            bit 6: zero-initialize segment
        DS:DX -> ASCIZ name (must begin with "\SHAREMEM\")
Return: CF clear if successful
            AX = segment address of shared memory global object
        CF set on error
            AX = error code (06h,08h) (see AH=59h)
Desc:   create an area of memory which may be accessed by multiple processes
Notes:  shared memory objects are created as special files (thus the
          restriction on the name)
        on successful creation, the reference count is set to 1
SeeAlso: AX=8402h,INT 15/AX=DE19h