Date:	Wed, 3 Jan 2001 18:48:26 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	jvasquez AT getntds DOT com
cc:	djgpp AT delorie DOT com
Subject:	Re: Linear memory and Physical Memory
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On Wed, 3 Jan 2001 jvasquez AT getntds DOT com wrote:

> How do I convert a Linear memory address to physical address?

You don't :-(.

The mapping between linear and physical addresses is inaccessible, except
if you use privileged instructions to read the page tables used by the
CPU's memory-mapping hardware.  Most DPMI servers won't let you use those
privileged instructions. 

> I call __dpmi_allocate_memory() to obtain a linear address for a
> buffer. I now need to program my PCI adapter with the physical memory
> for DMA output. 
> How do I do this?

There are several solutions of this available for DMA.  They are all 
described in section 18.13 of the DJGPP FAQ list.  If something there is 
unclear, please ask specific questions.

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