INT 10 - Everex Extended Video BIOS - RETURN EMULATION STATUS
        AX = 7000h
        BX = 0000h
Return: AL = 70h if Trident-based Everex card
        CL = monitor type (see below)
        CH = feature bits (see below)
        DX = video board info
            bits 4-15: board ID model
            bits 0-3:  board ID revision
        DI = BCD BIOS version number
Note:   board models for Trident-based Everex cards:
            236h Ultragraphics II
            620h Vision VGA
            673h EVGA
            678h Viewpoint
SeeAlso: AX=5F01h,AH=FF"Oak"

Values for monitor type:
 00h    mono
 01h    CGA
 02h    EGA
 03h    digital multifrequency
 04h    IBM PS/2
 05h    IBM 8514
 06h    SuperVGA
 07h    analog multifrequency
 08h    super multifrequency

Bitfields for feature bits:
 bits 7,6  memory size
        00 = 256K
        01 = 512K
        10 = 1024K
        11 = 2048K
 bit 5  special oscillator present
 bit 4  VGA protect enabled
 bit 0  6845 emulation

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