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From: Tom Phelan <phelan AT vibes DOT ultranet DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Converting linear addresses to physical?
Date: 13 Jun 1995 00:18:53 GMT
Organization: UltraNet Communications, Inc.
Lines: 17
Nntp-Posting-Host: vibes.ultranet.com
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

Hi,

I'm writing a driver for a PCI bus card that interfaces to a color
copier.  This card is a PCI bus master that uses its on-board DMA
to dump a frame buffer in the PC's memory to the copier.  The frame
buffer is up to 48M bytes, so I can't use DOS memory, but I can use
DJGPP to malloc the necessary memory.  The problem is I can't seem
to convert the linear address that DJGPP uses to the physical address
the DMA controller needs.  Does anyone have any suggestions?

By the way, DPMI function 0x0800 does just the opposite of what I
need.  It converts a physical address to linear.  I already use that
to get at the PCI card local memory - now I need to turn this around.

Any help will be greatly appreciated.

Tom Phelan