INT 15 - DESQview v2.50+ - "ADDINSTANCEDATA" - ADD PER-TASK SAVE/RESTORE AREA
        AX = DE27h
        BX = type
            0000h process
            0001h task
        ES:DI -> list of Instance Item Structures (see below)
Return: CF clear if successful
            AX = ???
            BX = ???
        CF set on error
            AX = error code???
                0004h invalid BX value
Note:   DESQview 2.50-2.52 are distributed as part of DESQview/X v1.0x.
SeeAlso: INT 2F/AX=DE08h,INT 2F/AX=DE09h

Format of Instance Item Structure [one element of list]:
Offset  Size    Description
 00h    WORD    length of data area DESQview should save and restore on context
                switches (0000h = end of list)
 02h    DWORD   pointer to area to be saved/restored

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