INT 10 - Chips & Technologies Extended BIOS - SET PREPROGRAMMED EMULATION
        AX = 5F01h
        BL = emulation type (see below)
Return: AL = 5Fh if function supported
            AH = status
                00h unsuccessful
                01h successful
SeeAlso: AX=5F00h,AX=5F02h,AH=FFh"Oak"

Values for emulation type:
 00h,01h reserved
 02h    CGA
 03h    MDA
 04h    Hercules
 05h    EGA
 06h    VGA

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