From:	Martin_Czamai AT peak-service DOT com (Martin Czamai)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Accessing memory above an adress of 1MB
Date:	Mon, 09 Aug 1999 11:10:10 GMT
Message-ID:	<37aeb1ba.11535499@NotesXNT>
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

Hello!

I want to access the memory space given from a BAR (base adress
register) of a PCI controller. (the adress is dynamic allocated by the
system)
Therefore I wrote a function that returns the (absolute) adress that
has to be accessed. Usually it is around 0xFFFFF000 .
I used __djgpp_map_physical_memory (mappedBAR, NoBytes, BaseAdr) for
mapping the device to a created memory block named 'mappedBAR'; the
number of bytes to map (NoBytes) is a multiple of a mem-page found
with __dpmi_get_page_size(&NoBytes)  (4096 bytes) and the base adress
(BaseAdr) is equal the absolute address of the BAR.
My problem is, that the __djgpp_map_physical_memory (mappedBAR,
NoBytes, BaseAdr) returns EACCES as errno, wich is a rejection of the
request to the  DPMI server. What does this message exactly mean?
Who could help me getting started to access this memory?
I am using RHIDE 1.4.
Please send your reply to Martin_Czamai AT peak-service DOT com .
Thank you!

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