Int 21 Fn F8  - DOS V2.11 - Set Oem Int 21 Handler                         [D]

   AH = F8h
   DS:DX -> OEM INT 21 handler for functions F9h to FFh
        FFFFh:FFFFh disables OEM handler

Notes: this function is supported by Toshiba T1000 ROM MS-DOS 2.11
   calls to AH=F9h through AH=FFH will return AL=00h if no handler set
   handler is called with all registers exactly as set by caller, and
     should exit with IRET

See Also: AH=F9h"OEM"