From:	"Miles F. Bintz Ii" <bintzimf AT clarkson DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Access phys. mem above 1 meg
Date:	Thu, 1 Oct 1998 11:15:59 -0400
Organization:	Clarkson Univeristy
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I've read the FAQs but I still seem to be missing a piece of
information...

I want to access physical address 0xDA000000.

I do the following:

__dpmi_meminfo mi;
mi.size = 0xfffff;
mi.address = 0xDA000000;
selector == __dpmi_allocate_ldt_descriptors(1);
__dpmi_physical_address_mapping(&mi);
__dpmi_lock_linear_region(&mi);
__dpmi_set_segment_base_address(selector, mi.address);
__dpmi_set_sedment_limit(selector, mi.size);

And so now I have a selector to my physical address at DA000000 right?
Well, what do I do with a selector?  I don't want to use the near/far ptr
hacks.

I would like to be able to say

 char *myptr = 0xda000000
 myptr[0] = 0xab;

for example.  But I dont know what the proper method of getting a selector
into a ponter is...  Can someone explaing to me what I need to do?

If I cant do what I stated above, can someone explain what happens
"behind the scenes" for a piece of data to get out to memory via a
selector?

Performance will be an issue futher down the road so I would like the
knowledge on how everything is working here in case I need to optimize
something.....

Thanks!
-Miles

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