INT 10H 1003H: Select Foreground Blink or Bold Background

                                                      Compatibility: EGA VGA
 Expects: AX    1003H
          BL    00H = enable bold backgrounds (16 background colors)
                01H = enable blinking foreground (8 background colors)
 Returns: (none)
    Info: This enables or disables blinking foreground colors in EGA/VGA
          text modes.  By default, the BIOS enables blinking foregrounds
          (characters blink when bit 7 of the Video Attribute is set).

          When foreground blink is disabled (BL=00H), all 16 colors are
          available for use as background colors.

   Notes: This fn is not available on CGAs^ and MDAs^.  To use this
          attractive and often-seen effect, you must program the CGA Mode
          Select Register, manually clearing bit 5.  See CGA I/O Ports.
          For instance:
            mov ax,40H
            mov es,ax
            mov dx,es:[063H]  ;get port address of the card
            add dx,4
            mov al,es:[065H]  ;get current value of Mode Select Register
            and al,0dfH       ;mask value by 1101 1111 (to clear bit 5)
            out dx,al         ;disable blink (set for bold background)
            mov es:[065H],al  ;save the new setting

See Also: INT 10H 10H: EGA/VGA Palette Functions
          INT 10H: Video Services
          EGA/VGA Data Areas