Int 10 Fn FF  - Topview - Update Screen From Shadow Buffer                 [V]

   AH = FFh
   CX = number of consecutive changed characters
   ES:DI -> first changed character in shadow buffer

Notes: avoid CX=0000h
   DESQview will discontinue the automatic screen updating initiated by
     AH=FEh after this call
   not supported (ignored) by DESQview/X 1.0x

See Also: AH=93h,AH=FEh