Talk:VGA Hardware: Difference between revisions
m (→Memory layout stuff: new section) |
(→"Memory Layout in 4-bit modes": new section) |
||
Line 29: | Line 29: | ||
Should we turn this section into a link to Bochs_VBE_extensions#Memory_layout_of_video_modes and copy the fleshed-out tidbits to the aforementioned article? Or the other way around? --[[User:Troy martin|Troy Martin]] 00:06, 27 December 2008 (UTC) |
Should we turn this section into a link to Bochs_VBE_extensions#Memory_layout_of_video_modes and copy the fleshed-out tidbits to the aforementioned article? Or the other way around? --[[User:Troy martin|Troy Martin]] 00:06, 27 December 2008 (UTC) |
||
== "Memory Layout in 4-bit modes" == |
|||
Surely the memory layout in 4-bit modes would be exactly the same as the memory layout in 16-colour modes? :-) |
|||
I assume this title was meant to be "Memory Layout in 4-colour (2-bit) modes". In this case AFAIK it's very similar to 4-bit/16-colour modes, except that only 2 planes are used (instead of 4 planes). The same applies to monochrome (1-bit, 2-colour) modes, where only one plane is used. |
Revision as of 07:23, 20 July 2009
Things that still need to be done:
- I need to reverse engineer more documentation for the sequencer.
- I need to test some additional GC bits for effects.
- Read Modes 0 and 1, Write modes 1,2,3 (this is easy as this documentation is rather complete. I Have not tested all details of this stuff)
- DAC Mask Register (the latest spec doesnt document it)
- Color Logic (There's more to this than the eye meets. I can write this from info out of Abrash's book, but i should still test it anyway. (It partially depends on the Sequencer)
- Sequencer: byte word doubleword mode, doublescanning, why 256-color modes have halved horizontal resolutions. Some of this depends on the sequencer operation...
- Combuster 17:15, 3 January 2007 (CST)
What you can do:
- Proof-read it, check for sanity.
- Comment on n00b-friendliness
- check registers and timings
- probably a lot more :)
- Combuster 16:55, 27 December 2006 (CST)
Detection
You mention checking for VGA compatability before use, but you make no mention of how to check for VGA compatability. I have never programmed for VGA so could not write this myself. --Tyler 18:28, 1 February 2007 (CST)
Well, I don't have any detection code either, because I know of no standard way existing of doing probes. You can deduce an probing method from the info listed, however, but it is not guaranteed to leave non-vga machines intact (see forum thread on ATI Mobile cards). You may want to google for it and contribute whatever you find - Combuster 03:38, 2 February 2007 (CST)
Well i have had a good search. Unfortunately it really is all so device independent that it is impossible to tell. I do recall once reading some kernel source code that verified a colour system was being used in it's initialisation routine. Unfortunately i have misplaced the code so if anyone comes across it, i think it may be used as such. I will keep searching. --Tyler 10:08, 2 February 2007 (CST)
Memory layout stuff
Should we turn this section into a link to Bochs_VBE_extensions#Memory_layout_of_video_modes and copy the fleshed-out tidbits to the aforementioned article? Or the other way around? --Troy Martin 00:06, 27 December 2008 (UTC)
"Memory Layout in 4-bit modes"
Surely the memory layout in 4-bit modes would be exactly the same as the memory layout in 16-colour modes? :-)
I assume this title was meant to be "Memory Layout in 4-colour (2-bit) modes". In this case AFAIK it's very similar to 4-bit/16-colour modes, except that only 2 planes are used (instead of 4 planes). The same applies to monochrome (1-bit, 2-colour) modes, where only one plane is used.