Mail Archives: djgpp/1995/02/14/09:07:42
> To access video memory directly (under DPMI) you have to use *far*
> pointers again (just when you thought you didn't need this far stuff
> anymore with DJGPP ;-) Find a DPMI 0.9 specification first.
>
> (1) allocate a LDT descriptor (0x0000) (this gives you a selector)
> (2) map to physical address (0x0800) i.e. where your video memory is
> (3) lock linear address (0x0600)
> (4) set segment base address (0x0007)
> (5) set segment limit (0x0008)
>
> You can use the far calls to set the selector, and access
> the video memory directly (i.e. unpaged).
You should only use the procedure above if you have a linear graphics
buffer in extended memory. If you are accessing video memory in the
1Mb area, use the conventional memory selector which is already set up.
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