VGA Register Programming (38715)
The information in this article applies to:
• Microsoft Mouse driver for MS-DOS 6.x
• Microsoft Mouse driver for MS-DOS 7.x
• Microsoft Mouse driver for MS-DOS 8.x
• Microsoft Mouse driver for MS-DOS 9.0
This article was previously published under Q38715
The EGA register interface also needs to be used for VGA programming.
When programming the VGA in EGA modes, using the interface is
identical to using it with the EGA. However, the VGA makes use of an
extra Attribute Controller register, 14h, Color Select. Where the EGA
has 20 Attribute Controller registers (0 through 13h), the VGA has 21
(0 through 14h).
Using function F7 of the EGA interface needs special attention. When
setting the Attribute Controller chip, all registers for the chip need
to be set any time the chip is accessed. If a register is not defined,
the register interface uses whatever random value is in that location.
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