INT 33 - GRTMOUSE v1.00+ - SET ACTIVE CHARACTERS
AX = 0103h
CH,CL,DH,DL = ASCII codes to be remapped to display mouse pointer
Note: the default active characters are D0h,D1h,D6h,D8h; the active
characters should be in the range C0h to DFh
SeeAlso: AX=0100h,AX=0104h