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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 |
In-Reply-To: | <3a534e1e.72667312@news.connectnet.com> |
Message-ID: | <Pine.SUN.3.91.1010103184541.4647F-100000@is> |
MIME-Version: | 1.0 |
Reply-To: | djgpp AT delorie DOT com |
Errors-To: | nobody AT delorie DOT com |
X-Mailing-List: | djgpp AT delorie DOT com |
X-Unsubscribes-To: | listserv AT delorie DOT com |
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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