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> OS Construction > SVGA/VESA in protected mode - Possible? |
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Dex4u 06 May 2007, 18:18
Hi,
There is about 3 ways to use vesa form pmode, 1. use vesa3 from pmode, but i have not to date found anyone who has got it working. 2. you can code a v86 see here: http://www.computerhope.com/jargon/v/virtreal.htm or 3. do what i do and go back to realmode, switch vesa modes and return to PM, (as you can use the LFB from pmode). Here is a veas demo i made to show how it is done. http://www.dex4u.com/demos/VesaDemo.zip This demo switch's between vesa 640x480 32bpp and text mode, it delays about 10 second between the two, then goes to real mode switch's and returns to pmode for 10 seconds. It comes with fasm source code and a exe to make a floppy bootable, with the demo on. So to run it you will need a vesa2 capable PC and floppy drive. NOTE: I was called ASHLEY4, when i wrote it. Last edited by Dex4u on 23 Feb 2008, 14:19; edited 1 time in total |
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06 May 2007, 18:18 |
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smoke 07 May 2007, 12:29
Hello,
Thanks for the reply! I think i'll go for the third option then  .
Im just curious if i can run such a program on windows without crashing? for example if i code a driver that will run in ring0 and wait till I press certain key this driver writes my program on the screen? |
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07 May 2007, 12:29 |
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DOS386 08 May 2007, 10:41
Quote: I think i'll go for the third option then Seems also good to me. See also my "VESA from DPMI" thread in DOS.
Quote: just curious if i can run such a program on windows without crashing Yeah ... people really should get rid of the assumption that everything must and will run in "Windows".  You can't run DOS code in Windows  (except some bad "NTVDM" emulation maybe), and even less no-OS code with raw mode switches. 
- Terminate your "Windows" (possible at all) ?
or - Use BOCHS or QEMU No-OS code can be tested in DOS with some care ... and limitations. 
Quote: if i code a driver that will run in ring0 and wait till I press certain key this driver writes my program on the screen OK, you can do 1000 times more complicated - maybe this would even work _________________ Bug Nr.: 12345 Title: Hello World program compiles to 100 KB !!! Status: Closed: NOT a Bug |
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08 May 2007, 10:41 |
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smoke 08 May 2007, 12:34
NTOSKRNL_VXE: hm i think you understood me wrong... i dont want an OS to emulate my code (for example windows) i was wondering if i can write on my screen while some os is running (windows or not windows)
so i either need to switch to realmode (but i have no idea what would that do other programs running at the same time) or find a way to call interrupts from protected mode. |
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08 May 2007, 12:34 |
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