Int 21 Fn 37DC  - Diet V1.43e - Set Address Of External Procedure          [k]

   AX = 37DCh
   BX = 899Dh ('DI' + 'ET')
   DS:DX -> external procedure

Return: AX = 0000h

Note:  the resident code will call the specified external procedure at the
     beginning of decompression and when compression is exited on failure

See Also: AX=37DDh

External procedure called with:
   STACK:  WORD    class
           FFFDh creation failed for unknown reasons
           FFFEh creation failed due to lack of space
           FFFFh file creation error
           else file handle of DIETed file to be decompressed
       DWORD   -> compressed filename
       DWORD   -> decompressed or temporary filename

Return: SI,DI,BP,DS,ES must be preserved by external procedure