INT 10H 12H BL=32H: Enable/Disable Video RAM & I/O Ports

                                                          Compatibility: VGA 
 Expects: AH    12H
          BL    32H
          AL    setting: 00H enable access
                         01H disable access
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 Returns: AH    12H if a valid value was passed in AL
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    Info: You can use this to suppress CPU access to video RAM and I/O
          ports on VGA-compatible displays.  It updates bit 0 of the
          VgaFlagsRec (at 0040:0089).

   Notes: You can disable an EGA card via bit 1 of port 3c2H.

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