INT 10H 12H BL=30H: Select Scan Lines for Text Modes

                                                          Compatibility: VGA
 Expects: AH    12H
          BL    03H
          AL    scan-lines code: 00H = 200 scan lines (EGA/VGA)
                                 01H = 350 scan lines (EGA/VGA)
                                 02H = 400 scan lines (VGA only)
 Returns: AH    12H if a VGA is active
    Info: This updates bits 0-3 in the EgaMiscInfo2Rec (at 0040:0088) and
          bits 4 and 7 of the VgaFlagsRec (at 0040:0089).

          Then, on the next INT 10H 00H call to switch to a text mode, the
          specified resolution will be in effect.

See Also: INT 10H 12H (EGA/VGA Special Functions/Alternate Select)
          INT 10H: Video Services
          EGA/VGA Data Areas