Compatibility: VGA
Expects: AH    12H
BL    36H
AL    setting: 00H enable refresh
01H disable refresh
Returns: AH    12H if a valid value was passed in AL
Info: This modifies bit 5 of the VGA's Sequencer Clocking Mode Register

You can draw complex graphics faster while refresh is disabled
(it avoids some enforced wait states).  Be sure to re-enable
refresh when finished updating video memory.

See Also: INT 10H 12H (EGA/VGA Special Functions/Alternate Select)
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INT 10H 12H BL=36H: Enable/Disable Screen Refresh