BL 00H = enable bold backgrounds (16 background colors)
01H = enable blinking foreground (8 background colors)
Info: This enables or disables blinking foreground colors in EGA/VGA
text modes. By default, the BIOS enables blinking foregrounds
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
mov dx,es:[063H] ;get port address of the card
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