VGA Hardware: Difference between revisions
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Planes 0 and 1 are written directly from video memory. Plane 0 is accessed on even addresses, plane 1 is accessed on odd addresses, with each consecutive word describing the next character. |
Planes 0 and 1 are written directly from video memory. Plane 0 is accessed on even addresses, plane 1 is accessed on odd addresses, with each consecutive word describing the next character. |
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=== Memory Layout in 4- |
=== Memory Layout in 4-color modes === |
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The CGA was limited to 4 concurrent colors, with two bits each. The EGA adds two extra bits by adding a pair of extra planes, increasing from the old two to the current four planes per pixel. If you want a 4-color mode that means you just should not touch planes 2 + 3. |
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'''Todo: i know close to nothing about 4-bit color modes, kindof before my age''' |
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'''Todo: determine the b/w/d, shift mode and odd/even mode for CGA compatibility (guesstimated at word mode, interleaved shift, odd/even enabled, i.e. equivalent to text mode except for the alphanumeric bit)''' |
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== The Graphics Controller == |
== The Graphics Controller == |
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