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Cirrus SVGA card (in bochs)
Posted: Mon Jan 29, 2007 10:41 am
by Seven11
Has anybody made a driver for the graphics card which bochs emulates? Would it be possible to look at that? I havn't found any good document telling me how to init and handle the setup.
Re: Cirrus SVGA card (in bochs)
Posted: Mon Jan 29, 2007 10:52 am
by Jeko
Seven11 wrote:Has anybody made a driver for the graphics card which bochs emulates? Would it be possible to look at that? I havn't found any good document telling me how to init and handle the setup.
look:
http://www.osdev.org/phpBB2/viewtopic.php?t=12348
Posted: Mon Jan 29, 2007 12:54 pm
by Seven11
that thread provides source for a video driver for the VMWare Video Driver... or am I wrong?
Posted: Tue Jan 30, 2007 9:40 am
by Jeko
Seven11 wrote:that thread provides source for a video driver for the VMWare Video Driver... or am I wrong?
you are wrong.
it provides sources for vmware and bochs.
Posted: Tue Jan 30, 2007 2:35 pm
by Seven11
so bochs and vmware emulates the same video card?
btw are you talking about
http://www.osdev.org/phpBB2/viewtopic.p ... c&start=15 the post by core?
Posted: Tue Jan 30, 2007 3:18 pm
by urxae
Seven11 wrote:so bochs and vmware emulates the same video card?
I don't think so.
I think he's actually talking about
this post on the first page of that thread, also by core.
Posted: Wed Jan 31, 2007 12:13 am
by os64dev
developping a cirrus driver for bochs restricts your OS to bochs and hardware using the cirrus graphics card. This is in general not a good think to do, better focus on vesa which supplies better resolutions on all/most graphics cards.
if you are using it for manipulating the text modes it is a different story. Vesa is harder then but the cirrus vga text mode doesn't behave any different then any other vga graphics card.
regards
Posted: Wed Jan 31, 2007 5:01 am
by Combuster
The driver in bochs is a VGA compatible - you can support a larger range of cards (including several NVidia's and ATIs) with such a driver instead of a CL driver, but i have to agree that a VESA driver is technically better, be it more difficult to implement. The VGA has IMO the best difficulty/support ratio you can get in Protected Mode.
various resources are here:
http://www.osdev.org/wiki/VGA_Hardware
http://www.osdev.org/wiki/VGA_Resources
http://www.osdever.net/FreeVGA/
and from my own os:
http://deimos.roeson.homelinux.net/comb ... vga_io.bas
http://deimos.roeson.homelinux.net/comb ... st_gfx.bas
These are written in BASIC, but should contain enough comments to write your own driver. You can have a look at Test_CRTC to see how to set a random resolution of your choice.
Posted: Wed Jan 31, 2007 1:05 pm
by Seven11
well I have a VESA driver (so far 32-bit and 24-bit) already, however I'm planning to build a interface for graphics cards to support more accelerated functions impossible to do (at least without loosing to much cpu power) like Z-buffering, 3D and so on.
A VGA driver is on the way for the init process because of the scrollning features.