Int 33 Fn 000A  - Ms Mouse V3.0+ - Define Text Cursor                      [M]

   AX = 000Ah
   BX = hardware/software text cursor
       0000h software
       CX = screen mask
       DX = cursor mask
       0001h hardware
       CX = start scan line
       DX = end scan line

Note:  when the software cursor is selected, the character/attribute data at
     the current screen position is ANDed with the screen mask and then
     XORed with the cursor mask

See Also: AX=0009h,INT 62/AX=007Eh