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DJGPP EGA MEMORY ACCESS http://forums.osdever.net/viewtopic.php?f=15&t=352 |
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Author: | smeezekitty [ Thu Apr 29, 2010 3:43 pm ] |
Post subject: | DJGPP EGA MEMORY ACCESS |
Ok, Ok, its not really OS dev but i thought you might be experienced in protected mode. I am using an EGA mono card and the memory is at 0xA000:0000 but when i try to access it directly, it segmentation faults. And if i try to access it with _fpokeb, the computer reboots for no reason. It is a 486/33 with 12 megs of ram . |
Author: | Kieran [ Thu Apr 29, 2010 3:53 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Have you got a valid GDT? |
Author: | smeezekitty [ Thu Apr 29, 2010 3:57 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
GDT = Global descriptor table? Protected mode is setup by a dpmi server so i assume so, but i am a noob in protected mode. |
Author: | Kieran [ Thu Apr 29, 2010 4:01 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Hmm, i thought you were talking about code compiled in GJGPP, running on a bare pc. Can you describe the environment? OS? |
Author: | smeezekitty [ Thu Apr 29, 2010 4:05 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Its MS-DOS 6.0. |
Author: | Kieran [ Thu Apr 29, 2010 4:15 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Doesnt MSDOS have an EGA interface or driver??? |
Author: | smeezekitty [ Thu Apr 29, 2010 4:22 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
I meant graphics mode |
Author: | Kieran [ Fri Apr 30, 2010 6:59 am ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Yeah I know mate, im not sure if direct acces is allowd to that memory??? But i know there are EGA drivers that provide interrupt service for EGA displays... |
Author: | smeezekitty [ Fri Apr 30, 2010 1:34 pm ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
Definitely possible: http://www.allegro.cc/manual/api/direct ... eo-memory/ |
Author: | smeezekitty [ Sun May 02, 2010 12:25 am ] |
Post subject: | Re: DJGPP EGA MEMORY ACCESS |
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